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Effect of the intracellular localization of a Gd‐based imaging probe on the relaxation enhancement of water protons
Author(s) -
Terreno Enzo,
Geninatti Crich Simonetta,
Belfiore Simona,
Biancone Luigi,
Cabella Claudia,
Esposito Giovanna,
Manazza Andrea D.,
Aime Silvio
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20793
Subject(s) - cytoplasm , intracellular , pinocytosis , extracellular , vesicle , biophysics , relaxation (psychology) , chemistry , electroporation , nuclear magnetic resonance , cell , endocytosis , membrane , biochemistry , biology , physics , neuroscience , gene
Gd‐HPDO3A has been internalized into rat hepatocarcinoma cells in the cytoplasm (by electroporation) or in intracellular vesicles (by pinocytosis), respectively. In the former case, the observed relaxation rates are likely dependent upon the amount of internalized paramagnetic complex, whereas in the latter case the relaxation enhancement is “quenched” to a plateau value (about 3 s −1 ) when the entrapped amount of Gd‐chelate is higher than 1 × 10 10 Gd/cell. The observed behavior has been accounted in terms of a theoretical treatment based on equations formally derived by Labadie et al. (J Magn Reson B 1994;105:99–102). On this basis, entrapment into intracellular vesicles has been treated as a three‐site water exchange (extracellular/cytoplasm/vesicle compartments), whereas the cell pellets containing the paramagnetic agent spread out in the cytoplasm can be analyzed by a two‐site exchange system. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.