title: Effect of the intracellular localization of a Gd-based imaging probe on the relaxation enhancement of water protons.
abstract: 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 x 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.
authors.affiliation: Department of Chemistry, I.F.M., and Center for Molecular Imaging (CIM), University of Torino, Torino, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Terreno
authors.forename: Simonetta
authors.initials: S
authors.lastname: Geninatti Crich
authors.forename: Simona
authors.initials: S
authors.lastname: Belfiore
authors.forename: Luigi
authors.initials: L
authors.lastname: Biancone
authors.forename: Claudia
authors.initials: C
authors.lastname: Cabella
authors.forename: Giovanna
authors.initials: G
authors.lastname: Esposito
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Manazza
authors.forename: Silvio
authors.initials: S
authors.lastname: Aime
mesh_terms: D000818:Animals; D002468:Cell Physiological Phenomena; D002614:Chelating Agents; D018274:Electroporation; D005682:Gadolinium; D006571:Heterocyclic Compounds; D017136:Ion Transport; D008279:Magnetic Resonance Imaging; D015388:Organelles; D009942:Organometallic Compounds; D010873:Pinocytosis; D051381:Rats; D014407:Tumor Cells, Cultured; D014867:Water / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D014867:Water; D005682:Gadolinium