Lipoproteins hydroperoxide determination

Lophine, chemiluminescence, 1212 LOQ (Limits of quantitation), 625 Low-density lipoprotein (LDL) o,o -dityrosine residues, 610 hydroperoxide determination, 675 oxidation, 610-11, 612, 613, 671 oxidized antibody determination, 633 TEARS assay, 667... 

The first FI-CL system for lipid hydroperoxide determination, published in 1993, was based on luminol as the CL reagent and microperoxidase as the catalyst. The optimized system was used for measuring lipid hydroperoxides in native low-density lipoprotein (LDL) (Cominacini et al. 1993). The FI-CL system consisted of two pumps, an autosampler, and a chemiluminescent detector with a T-mixing coil. Samples were injected by using an autosampler and mixed with luminescent reagent (3 (iM luminol and 1 xM microperoxidase in 0.1 M carbonate buffer, pH 10). The calibration curve was obtained using linoleic acid, and a detection limit of 3 pmol linoleic acid hydroperoxide was reached. 

A correlation may be established between the concentration of oxidized lipids and the TEARS value, expressed as MDA equivalents, in uM units. Correction is due in some cases for the interference by dyes or other factors. For example, the presence of anthocyanins in red cabbage leaves or turbiditjf causes overestimation of lipid hydroperoxides in plant tissue by the TEARS method. TEARS was used to assert the level of endogenous peroxides in hypo- and hyperthyroidism, both conditions being characterized by low lipid and lipoprotein plasma levels and enhanced oxidative metabolism . In a procedure for determination of TEARS in edible oils, the sample is placed in a centrifuge at 12000 g before measuring at 532 nm (e = 1.56 x 10 M cm ) . A usual procedure for determination of TEARS in certain complex matrices involves steam distillation of the aldehydes responsible for the value, instead of extraction. In nitrite-cured meats, excess nitrite may cause nitrosation of MDA, thus interfering with distillation. To avoid this interference sulfanilamide is added, which is converted to a diazonium salt and... 

N4. Nourooz-Zadeh, J., Tajaddini-Sarmadi, J., Ling, K. L., and Wolff, S. P., Low-density lipoprotein is the major carrier of lipid hydroperoxides in plasma. Relevance to determination of total plasma lipid hydroperoxide concentrations. Biochem. J. 313, 781-786 (1996). 

The oxidation products of plasma and lipoprotein phospholipids have been the subject of extensive study by chromatographic and mass spectrometric methods. Earlier, workers had reported the simultaneous determination of phospholipid hydroperoxides and cholesteryl ester hydroperoxides in human plasma by HPLC with chemiluminescence monitoring. Lipid hydroperoxides were quantitatively extracted from human plasma with a mixture of -hexane and... 

The direct separation of phosphohpidhydroperoxides has now been achieved by further advances in HPLC and increased sensitivity by chemiluminescence detection. By reverse-phase HPLC, the hydroperoxides of phosphatidylcholine and phosphatidylethanolamine were separated and determined in stored spray-dried eggs (2.4. 4%), fresh ground meat (0.2%), and raw fish (0.4%). Silica HPLC with post-column chemiluminescence detection has been used to determine phospholipid hydroperoxides in human blood plasma and in the low-density lipoprotein fraction. 

Miyazawa, T., Eujimoto, K. and Oikawa, S-1. Determination of lipid hydroperoxides in low-density lipoprotein from human plasma using high performance liquid chromatography with chemiluminescence detection. Biomedical Chromatography 4, 131-134 (1990). 

Cominacini, E., A. M. Pastorino, A. McCarthy, M. Campagnola, U. Garbin, A. Davoli, A. Desantis, and V. Eocascio. 1993. Determination of lipid hydroperoxides in native low-density-lipoprotein by a chemiluminescent flow-injection assay. Biochim. Biophys. Acta 1165 279-287. 

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