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Prepublished online as a Blood First Edition Paper on March 6, 2003; DOI 10.1182/blood-2002-03-0914. This Article Full Text (PDF) All Versions of this Article: 2002-03-0914v1 102/1/357    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Darbari, D. Articles by Kurantsin-Mills, J. Search for Related Content PubMed PubMed Citation Articles by Darbari, D. Articles by Kurantsin-Mills, J. Social Bookmarking                   What's this? Submitted March 25, 2002 Accepted February 3, 2003 Fluorescence measurements of the labile iron pool of sickle erythrocytes Deepika Darbari, Mark Loyevsky, Victor Gordeuk, John A Kark, Oswaldo Castro, Sohail Rana, Victor Apprey, and Joseph Kurantsin-Mills* Center for Sickle Cell Disease, Howard University, College of Medicine and Howard University Hospital, Washington, DC, USA Department of Biophysics and Physiology, Howard University, College of Medicine and Howard University Hospital, Washington, DC, USA Department of Pediatrics, Howard University, College of Medicine and Howard University Hospital, Washington, DC, USA Department of Microbiology, Howard University, College of Medicine and Howard University Hospital, Washington, DC, USA Department of Medicine, Howard University, College of Medicine and Howard University Hospital, Washington, DC, USA Statistical Genetics and Bioinformatics Unit, Howard University, College of Medicine, Washington, DC, USA * Corresponding author; email: jkurantsin-mills{at}howard.edu. Sickle erythrocytes have increased ferritin and increased molecular iron on the inner membrane leaflet, and we postulated that cytosolic labile iron is also elevated. We used the fluorescent metallosensor, calcein, and a permeant Fe2+ chelator to estimate labile cytosolic Fe2+ and calcein plus Fe3+ chelator to estimate total cytosolic labile iron (Fe2+ + Fe3+). We measured membrane nonheme iron by its reactivity with ferrozine. As estimated by calcein and Fe2+ chelator, the mean ± SD labile iron concentration was significantly lower in hemoglobin SS (n=29) than hemoglobin AA (n=17) erythrocytes (0.56±0.35 µM versus 1.25±0.65µM; P<0.001). In contrast, as estimated by calcein and Fe3+ chelator, total erythrocyte labile iron was similar in hemoglobin SS (n=12) and hemoglobin AA (n=10)participants (1.75±0.41µM versus 2.14±0.93µM; P=0.2). Mean membrane nonheme iron levels were higher in hemoglobin SS cells than hemoglobin AA cells (0.0016x10-4 versus 0.0004x10-4 fmoles/cell; p=0.01), but much lower than the mean amounts of total labile iron (1.6-1.8x10-4 fmoles/cell) or hemoglobin iron (18,000-19,000x10-4 fmoles/cell). Both membrane iron and labile iron were much less than the mean amount of iron potentially present in erythrocyte ferritin as calculated from results of other investigators (15x10-4 versus 34x10-4 fmoles/cell in HbAA versus HbSS erythrocytes). We conclude that cytosolic labile iron is not elevated in hemoglobin SS erythrocytes and that elemental membrane iron is present in only trace amounts. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: D. T. Jones, I. S. Trowbridge, and A. L. Harris Effects of transferrin receptor blockade on cancer cell proliferation and hypoxia-inducible factor function and their differential regulation by ascorbate. Cancer Res., March 1, 2006; 66(5): 2749 - 2756. [Abstract] [Full Text] [PDF]

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