Chu W J, Elgavish G A
Department of Medicine, University of Alabama at Birmingham 35294, USA.
NMR Biomed. 1995 Jun;8(4):159-63. doi: 10.1002/nbm.1940080404.
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.
在本研究中，通过共价酰胺键将二乙三胺五乙酸（DTPA）连接到葡聚糖大分子（相对分子质量约为6000）上，合成了共轭大分子配体DTPA-酰胺-葡聚糖。随后，DTPA-酰胺-葡聚糖与两种镧系金属离子镝（Dy）或钆（Gd）中的任一种形成络合物。对Dy（DTPA-酰胺-葡聚糖）诱导的顺磁23Na NMR位移和Gd（DTPA-酰胺-葡聚糖）诱导的弛豫率（ρ1）进行了表征。Dy（DTPA-酰胺-葡聚糖）诱导的23Na NMR位移比Dy（DTPA）诱导的位移大25%。溶液中钙离子浓度增加对Dy（DTPA-酰胺-葡聚糖）诱导的位移和Dy（DTPA）诱导的位移均无影响。DTPA-酰胺-葡聚糖在0.23 T磁场下的体外ρ1为8.4（mM s）-1，在0.47 T磁场下为9.3（mM s）-1，表明具有正磁场依赖性。
