title: Gadolinium and dysprosium chelates of DTPA-amide-dextran: synthesis, 1H NMR relaxivity, and induced 23Na NMR shift.
abstract: In this study the conjugated macromolecular ligand, diethylenetriaminepentaacetic acid (DTPA)-amide-dextran, was synthesized by attaching DTPA to the dextran macromolecule (M(r) approximately 6000) by a covalent amide bond. Subsequently, DTPA-amide-dextran was complexed with either of the two lanthanide metal ions dysprosium (Dy) or gadolinium (Gd). The paramagnetic 23Na NMR shift induced by Dy(DTPA-amide-dextran) and the relaxivity (rho 1) induced by Gd(DTPA-amide-dextran) were characterized. Dy(DTPA-amide-dextran) induced a 25% larger 23Na NMR shift than that induced by Dy(DTPA). Neither the shift induced by Dy(DTPA-amide-dextran) nor the shift induced by Dy(DTPA) was affected by increasing levels of calcium ions in the solution. offDTPA-amide-dextran) exhibited an in vitro rho 1 of 8.4 (mM s)-1 at a 0.23 T magnetic field and 9.3 (mM s)-1 at a 0.47 T magnetic field, thus indicating a positive magnetic field dependence.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham 35294, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Chu
authors.forename: G A
authors.initials: GA
authors.lastname: Elgavish
mesh_terms: D000577:Amides / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D004419:Dysprosium / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D004369:Pentetic Acid / Q000031:analogs & derivatives / Q000737:chemistry*; D011522:Protons; D012975:Sodium Isotopes
chemical_list: D000577:Amides; D002614:Chelating Agents; D003911:Dextrans; D009942:Organometallic Compounds; D011522:Protons; D012975:Sodium Isotopes; D004419:Dysprosium; D004369:Pentetic Acid; C055865:dysprosium DTPA; D005682:Gadolinium