Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/10509
Title: Effects of negatively charged shift reagents on red blood cell morphology, lithium ion transport, and membrane potential
Authors: Ramasamy, Ravichandran 
Freitas, Duarte Mota de 
Jones, Warren 
Wezeman, Frederick 
Labotka, Richard 
Geraldes, Carlos F. G. C. 
Issue Date: Oct-1990
Publisher: American Chemical Society
Citation: Inorganic Chemistry. 29:20 (1990) 3979-3985
Abstract: Lanthanide shift reagents have been used extensively in multinuclear magnetic resonance (NMR) applications in order to obtain information regarding ion distribution and transport in cellular systems. The aqueous reagents used in this study were Dy(PPP)J-, Tm( PPP)J-, Dy(TTHA)’-, Dy(PcPcP);-, and Dy(DOTP)’-, where Dy3+ and Tm3+ represent dysprosium and thulium ions and PPPs-, TTHA6-, PcPcPs-, and DOTP*- denote the triphosphate, triethylenetetraminehexaacetate, bis(dihydroxyphosphiny1- methyl)phosphinate, and I ,4,7,1 O-tetrazacyclododecane-N,N’,N”,N”’-tetrakis(methanephosphonate) ligands, respectively. The apparent size and shape of Li+-free RBCs (red blood cells), studied by both scanning electron microscopy and Coulter counter methods, were unchanged by the presence of the above shift reagents at concentrations lower than 10 mM. However, Li+ incubation changed both the shape and size of RBCs. The rates of Na+-Li+ exchange in Li+-loaded RBCs measured by 7Li NMR spectroscopy in the presence of Dy(PPP);-, TI~(PPP),~o-r, D~(PcPcP),~w-e re significantly higher than the rates measured in the absence of shift reagents by atomic absorption or in the presence of DY(TTHA)~o-r DY(DOTP)~b-y 7Li NMR spectroscopy. 31P and I9F NMR measurements of the membrane potential of Li+-free RBCs revealed that the shift reagents studied (except for Dy(TTHA)”) do change the membrane potential, with the most negatively charged reagents having the largest effect. Thus, shift reagents must be used with caution in physiological NMR studies and in particular RBC applications.
URI: http://hdl.handle.net/10316/10509
ISSN: 0020-1669
DOI: 10.1021/ic00345a014
Rights: openAccess
Appears in Collections:FCTUC Química - Artigos em Revistas Internacionais

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