| 11. |
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| 12. |
- Barregård, Lars, 1948, et al.
(författare)
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Human and Methodological Sources of Variability in the Measurement of Urinary 8-Oxo-7,8-dihydro-2 '-deoxyguanosine
- 2013
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 18:18, s. 2377-2391
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (r(p) 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.
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| 13. |
- Basu, Samar, et al.
(författare)
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Eicosanoids and Adipokines in Breast Cancer : From Molecular Mechanisms to Clinical Considerations
- 2013
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 18:3, s. 323-360
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Forskningsöversikt (refereegranskat)abstract
- Chronic inflammation is one of the foremost risk factors for different types of malignancies, including breast cancer. Additional risk factors of this pathology in postmenopausal women are weight gain, obesity, estrogen secretion, and an imbalance in the production of adipokines, such as leptin and adiponectin. Various signaling products of transcription factor, nuclear factor-kappaB, in particular inflammatory eicosanoids, reactive oxygen species (ROS), and cytokines, are thought to be involved in chronic inflammation-induced cancer. Together, these key components have an influence on inflammatory reactions in malignant tissue damage when their levels are deregulated endogenously. Prostaglandins (PGs) are well recognized in inflammation and cancer, and they are solely biosynthesized through cyclooxygenases (COXs) from arachidonic acid. Concurrently, ROS give rise to bioactive isoprostanes from arachidonic acid precursors that are also involved in acute and chronic inflammation, but their specific characteristics in breast cancer are less demonstrated. Higher aromatase activity, a cytochrome P-450 enzyme, is intimately connected to tumor growth in the breast through estrogen synthesis, and is interrelated to COXs that catalyze the formation of both inflammatory and anti-inflammatory PGs such as PGE(2), PGF(2 alpha), PGD(2), and PGJ(2) synchronously under the influence of specific mediators and downstream enzymes. Some of the latter compounds upsurge the intracellular cyclic adenosine monophosphate concentration and appear to be associated with estrogen synthesis. This review discusses the role of COX- and ROS-catalyzed eicosanoids and adipokines in breast cancer, and therefore ranges from their molecular mechanisms to clinical aspects to understand the impact of inflammation.
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| 14. |
- Basu, Samar
(författare)
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F2-isoprostanes in human health and diseases : from molecular mechanisms to clinical implications
- 2008
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert. - 1523-0864 .- 1557-7716. ; 10:8, s. 1405-1434
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Forskningsöversikt (refereegranskat)abstract
- Oxidative stress is implicated as one of the major underlying mechanisms behind many acute and chronic diseases, and involved in normal aging. However, the measurement of free radicals or their end products is complicated. Thus, proof of association of free radicals in pathologic conditions has been absent. Isoprostanes are prostaglandin-like bioactive compounds that are biosynthesized in vivo independent of cyclooxygenases, principally through free-radical catalyzation of arachidonic acid. Isoprostanes are now considered to be reliable biomarkers of oxidative stress, as evidenced by an autonomous study organized recently by the National Institutes of Health (NIH) in the United States. A number of these compounds have potent biologic activities such as vasoconstrictive and certain inflammatory properties. Isoprostanes are involved in many human diseases. Additionally, elevated levels of F2-isoprostanes have been seen in normal human pregnancy and after intake of some fatty acids, but their physiologic assignments have not yet been distinctive. This evidence indicates that measurement of bioactive F2-isoprostanes in body fluids offers a unique noninvasive analytic utensil to study the role of free radicals in physiology, oxidative stress–related diseases, experimental acute or chronic inflammatory conditions, and also in the assessment of various antioxidants, radical scavengers, and drugs.
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| 15. |
- Basu, Samar, et al.
(författare)
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Is There any Role for Serum Cathepsin S, CRP levels on Prognostic Information in Breast Cancer? : The Swedish Mammography Cohort
- 2015
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 23:16, s. 1298-1302
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer is the most common cancer among women, and both low-grade inflammation and cathepsins might have important roles in breast cancer. We questioned whether prediagnostic circulating levels of C-reactive protein (CRP), cathepsin B and cathepsin S were associated with breast cancer risk. Sixty-nine incident breast cancer cases diagnosed after blood collection and 719 controls from the Swedish Mammography Cohort were analysed for systemic CRP, cathepsin B and cathepsin S. Cathepsin S and inflammation (hsCRP) adjusted cathepsin S were inversely associated with breast cancer risk (cathepsin S: OR for top vs. bottom tertile = 0.46; 95% CI = 0.23-0.92; Ptrend = 0.02; hsCRP adjusted cathepsin S: OR of 0.44; 95% CI = 0.22-0.87; Ptrend = 0.02). hsCRP was significantly associated with increased breast cancer risk (OR for top vs. bottom tertile= 2.01; 95% CI = 1.02-3.95; Ptrend = 0.04). No significant association was observed between cathepsin B and breast cancer risk (OR for top vs. bottom tertile= 0.67; 95% CI = 0.32-1.40; Ptrend = 0.30). These observations lead to hypothesis that levels of cathepsin S and hsCRP observed in women who later developed breast cancer may provide prognostic information regarding tumor development and need to be evaluated in prospective studies.
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| 16. |
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| 17. |
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| 18. |
- Brnjic, Slavica, et al.
(författare)
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Induction of Tumor Cell Apoptosis by a Proteasome Deubiquitinase Inhibitor Is Associated with Oxidative Stress
- 2014
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 21:17, s. 2271-2285
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Tidskriftsartikel (refereegranskat)abstract
- Aims: b-AP15 is a recently described inhibitor of the USP14/UCHL5 deubiquitinases (DUBs) of the 19S proteasome. Exposure to b-AP15 results in blocking of proteasome function and accumulation of polyubiquitinated protein substrates in cells. This novel mechanism of proteasome inhibition may potentially be exploited for cancer therapy, in particular for treatment of malignancies resistant to currently used proteasome inhibitors. The aim of the present study was to characterize the cellular response to b-AP15-mediated proteasome DUB inhibition. Results: We report that b-AP15 elicits a similar, but yet distinct, cellular response as the clinically used proteasome inhibitor bortezomib. b-AP15 induces a rapid apoptotic response, associated with enhanced induction of oxidative stress and rapid activation of Jun-N-terminal kinase 1/2 (JNK)/activating protein-1 signaling. Scavenging of reactive oxygen species and pharmacological inhibition of JNK reduced b-AP15-induced apoptosis. We further report that endoplasmic reticulum (ER) stress is induced by b-AP15 and is involved in apoptosis induction. In contrast to bortezomib, ER stress is associated with induction of alpha-subunit of eukaryotic initiation factor 2 phosphorylation. Innovation: The findings establish that different modes of proteasome inhibition result in distinct cellular responses, a finding of potential therapeutic importance. Conclusion: Our data show that enhanced oxidative stress and ER stress are major determinants of the strong apoptotic response elicited by the 19S DUB inhibitor b-AP15. Antioxid. Redox Signal. 21, 2271-2285.
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| 19. |
- Bulow, Leif, et al.
(författare)
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Redox Chemistry of Hemoglobin-Associated Disorders
- 2017
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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 26:14, s. 745-747
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Forskningsöversikt (refereegranskat)abstract
- This Forum addresses oxidative reactions of hemoglobin (Hb) and explores the underlying mechanisms of some of these reactions that contribute to the pathophysiology associated with hemolytic anemia and Hb-based oxygen therapeutics. A special focus of this Forum is on the understanding of naturally occurring mutations in human Hb and how these mutations were influenced overtime by variety of oxidative stresses. What emerges from these contributions is that some hemoglobinopathies involve mutant Hb that resists oxidative challenges, whereas the majority often result in circulatory disorder. The contributors provide in-depth and comprehensive overviews on selected key mechanisms underlying Hb oxidative reactions in health and in disease states and how this knowledge may help in the design of countermeasures against these oxidative and toxicological pathways. Antioxid. Redox Signal. 26, 745-747.
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| 20. |
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