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Wagner B.A.,The University of Lowa | Witmer J.R.,The University of Lowa | van't Erve T.J.,The University of Lowa | Buettner G.R.,The University of Lowa
Redox Biology | Year: 2013

Cells have a wide range of capacities to remove extracellular hydrogen peroxide. At higher concentrations of extracellular H2O2 (micromolar) the rate of removal can be approximated by a rate equation that is first-order in the concentration of H2O2 and cell density. Here we present a method to determine the observed rate constant for the removal of extracellular H2O2 on a per cell basis. Ln the cells examined, when exposed to 20 μM H2O2,these rate constants (kcell) range from 0.46 × 10-12 s-1 cell-1 L for Mia-PaCa-2 cells (human pancreatic carcinoma) to 10.4 x 10-12 s-1 cell-1 L for U937 cells (human histiocytic lymphoma). For the relatively small red blood cell kcell=2.9 × 10-12s-1 cell-1 L. These rate constants, kcell, can be used to compare the capacity of cells to remove higher levels of extracellular H2O2, as often presented in cell culture experiments. They also provide a means to estimate the rate of removal of extracellular H2O2, rate= -kcell [H2O2] (cells L-1), and the half-life of a bolus of H2O2. This information is essential to optimize experimental design and interpret data from experiments that expose cells to extracellular H2O2. © 2013 The Authors.

Mullins R.F.,The University of Lowa | Khanna A.,The University of Lowa | Schoo D.P.,The University of Lowa | Tucker B.A.,The University of Lowa | And 3 more authors.
Advances in Experimental Medicine and Biology | Year: 2014

Age-related macular degeneration (AMD) is a common, degenerative disease of the central retina affecting millions of elderly in the USA alone and many more worldwide. A better understanding of the pathophysiology of AMD will be essential for developing new treatments. In this review, we discuss the potential impact of complement complex deposition at the choriocapillaris of aging eyes and the relationship between choriocapillaris loss and drusen formation. We further propose a model that integrates genetic and anatomical findings in AMD and suggest the implications of these findings for future therapies. © Springer Science+Business Media, LLC 2014.

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