B Wallin

University of Gothenburg, Goeteborg, Västra Götaland, Sweden

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Publications (3)5.6 Total impact

  • G Camejo, B Wallin, M Enojärvi
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    ABSTRACT: Measurement of thiobarbituric acid reacting substances (TBARS), diene derivatives, and hydroperoxides are probably the most widely used procedures for evaluation of free radical-mediated oxidation of biological or model systems containing polyunsaturated fatty acids (PUFA). It is possible to write a sequence of rational reactions in which dienes formation comes first, followed by lipid hydroperoxides (LOOHs) production, and that terminates with fragmentation of the PUFA chains to carbonyl compounds that are TBARS. However, it appears that after the first few min, species of the three types co-exist even in simple suspensions of linoleic acid (1,2). These compounds are very reactive, especially in biological systems, and follow different rates of formation and conversion. Therefore, it is more informative to follow their kinetics of appearance and disappearance than to measure single time-points (3–5).
    Methods in Molecular Biology 02/1998; 108:377-87. DOI:10.1385/0-89603-472-0:377 · 1.29 Impact Factor
  • B Wallin, G Camejo
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    ABSTRACT: The oxidative modification of lipoproteins is of clinical importance because of potential contribution to atherogenesis [1, 2, 3]. An early step in the complex process of oxidation is the peroxidation of polyunsaturated fatty acids. We describe here a method for the Cu(II)-catalyzed oxidation of human low density lipoproteins with the subsequent analysis of hydroperoxides formation in a single microtitre plate. The procedure includes a modification of an iodometric peroxide assay for test tubes using a commercially available reagent. The microtitre plate method correlated well with the test tube procedure (r = 0.99) and showed comparable sensitivity and reproducibility. It was sensitive down to 0.5 nmol hydroperoxides/well and linear up to at least 20 nmol well-1. The method can handle several hundreds of samples a day with considerably less labour than the test tube procedure. It was well suited to monitor the kinetics of lipoprotein oxidation. The method was also used to test the potency of antioxidants, however, some antioxidants may interfere with the iodometric reaction and should be tested in the assay before use.
    Scandinavian Journal of Clinical and Laboratory Investigation 08/1994; 54(4):341-6. DOI:10.3109/00365519409087532 · 2.01 Impact Factor
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    ABSTRACT: Transition metals catalyze free radical-mediated oxidation of lipids and lipoproteins. This process is currently studied because of its potential relevance to pathological processes like atherosclerosis. Formation of thiobarbituric acid-reacting substances from polyenoic fatty acids is frequently used to follow oxidation of lipids and plasma lipoproteins. We describe here how Cu(II)- and Fe(III)-catalyzed oxidation of human low density lipoprotein or soy bean phospholipids and the photometric evaluation of the thiobarbituric acid-reaching substances formed can be conducted in the same 96-well microtiter plate. The procedure showed a correlation of 0.98 with conventional two-stage fluorimetric and spectrophotometric methods and also showed better reproducibility. The plate method can handle up to one plate per hour with considerably less labor than the test tube assays. The plate procedure required small volumes of diluted samples of lipoproteins lipids and reagents. The method was suitable for testing the concentration-dependent antioxidant potency of substances like probucol, butylated hydroxytoluene, and alpha-tocopherol. The method can also be used to follow the kinetics of oxidation of lipoproteins.
    Analytical Biochemistry 02/1993; 208(1):10-5. DOI:10.1006/abio.1993.1002 · 2.31 Impact Factor