Reactive oxygen species (ROS), important mediators of cell and tissue injury during inflammation, are produced by several types of inflammatory cells. The formation of ROS can be monitored by detection of lipid peroxidation products. The extremely broad spectrum of biological effects of aldehydic lipid peroxidation products has necessitated the development of a technique that enables the sensitive routine quantitation of aldehydes formed in biological materials. MalondiaJdehyde (MDA) is a by-product of enzymatic eicosanoid formation and an endproduct of nonenzymatic peroxidation of polyunsaturated fatty acids with three or more bisallylic double bonds, The determination of the thiobarbituric acid derivative of MDA (TBA-MDA) is a widely used method for estimating overall lipid peroxidation. We describe a rapid, isocratic, simple, and sensitive high-performance liquid chromatographic (HPLC) method with spectrafluorimetric detection for measurement oF MDA-TBA in human biological samples such as plasma, urine, wound secretions, amniotic fluid, sputum and tissue samples. By use of this method, picomole quantities of MDA can be readily and specifically detected in different biological materials. Coefficients of variation of repeated MDA-TBA assays were 4.4% within run and 6.9% from run to run. Reference values are given for a variety of human body fluids and for rat tissues.

Neutrophil granulocyte leukocytes (neutrophils) play fundamental role in the innate immune response. In the presence of adequate stimuli, neutrophils release excessive amount of reactive oxygen species (ROS) that may induce cell and tissue injury. Oxidative burst of neutrophils acts as a double-edged sword. It may contribute to the pathology of atherosclerosis and brain injury but is also necessary in resolving infections. Moreover, neutrophil-derived ROS may also have both a tumor promoting and tumor suppressing role. ROS have a specific activities and diffusion distance, which is related to their short lifetime. Therefore, the manner in which ROS will act depends on the cells targeted and the intra- and extracellular levels of individual ROS, which can further cause production of reactive aldehydes like 4-hydroxynonenal (HNE) that act as a second messengers of ROS. In this review we discuss the influence of neutrophil mediated extracellular redox reactions in ischemia reperfusion injury, transplant rejection and chronic diseases (atherosclerosis, inflammatory bowel diseases and cancer). At the end a brief overview of cellular mechanisms to maintain ROS homeostasis is given.

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