Proton Relaxation Times in Paramagnetic Solutions

Bloembergen, N.

doi:10.1063/1.1743771

Cited by 1,006 publications

(537 citation statements)

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“…Data were analysed using the classical inner sphere (Solomon 1955;Bloembergen 1957) and outer sphere (Freed 1978) theories. The assumption was made that either the complex is included only in the outer layer of the liposome membrane or that the complex is present in both layers with a very fast water exchange rate between the inside and outside liposomal compartments.…”

Section: Resultsmentioning

confidence: 99%

“…All samples were diluted 10 times and the temperature was maintained at 37°C. 1 H NMRD data were fitted according to the theoretical inner sphere model described by Solomon and Bloembergen and to the outer sphere contribution described by Freed (Solomon 1955;Bloembergen 1957;Freed 1978). Calculations were performed with a previously described software (Muller et al1990).…”

Section: T 1 Measurementsmentioning

confidence: 99%

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Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

et al. 2005

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Three amphiphilic DTPA bisamide derivatives containing long-chain phenylalanine esters (with 14, 16 and 18 carbon atoms in the alkyl chain) were synthesized and their corresponding gadolinium(III) complexes were prepared. The attempts to form paramagnetic micelles carrying the gadolinium(III) complexes yielded unstable or polydisperse micelles implying that the presence of the bulky aromatic side groups in the amphiphilic Gd-DTPA bisamide complexes results in an inefficient packing of the paramagnetic complex into micelles. All complexes were efficiently incorporated into liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), yielding stable and monodisperse paramagnetic liposomes. All liposomes had a comparable size, typically between 120 and 160 nm. As a result of the reduced mobility of the gadolinium(III) complexes, solutions of these supramolecular structures show a higher relaxivity than solutions of Gd-DTPA. However, the relaxivity gain is lower compared to compounds consisting of purely aliphatic chains of the same length, most likely due to the less efficient packing or increased local mobility of the gadolinium(III) complex. In the case of the Gd-DTPA bisamide complex with 18 carbon atoms, the immobilization inside the liposomal structure is less effective, probably because the aliphatic chains of the complex are longer than the alkyl chains of the DPPC host, resulting in a relatively high local mobility. The paramagnetic liposomes containing the Gd-DTPA bisamide complexes with 14 carbon atoms showed the highest relaxivity because the optimal length match between the hydrophobic chains of the DPPC and the ligand allowed very efficient packing of the paramagnetic complex into the liposome.

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Section: Resultsmentioning

confidence: 99%

Section: T 1 Measurementsmentioning

confidence: 99%

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

et al. 2005

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“…In Figure 7 the chemical shift of the 23 Na resonance in solutions of Mn 2 + salts is depicted 15 . The shift is caused by scalar interaction 16 and it will be seen that the scalar interaction is most effective for chlorides. The Li+ chemical shift is much smaller 15 , the coupling constant is smaller but other factors arealso important 17 …”

Section: ~------'---------'--' -------'---mentioning

confidence: 99%

Intermolecular nuclear relaxation and molecular pair distribution in liquid mixtures

Göller¹,

Hertz²,

Tutsch³

1972

Pure and Applied Chemistry

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ABSTRACT7 Li and 23 Na relaxation times in aqueous solution of Li+ and Na+ in the presence of an increasing amount of Mn2+ are reported. From these measurements the cation-cation pair distribution function has been calculated. A distance ofapproach between Li+ (or Na +)and Mn 2 + of ~4.5A has been found.The intermolecular proton relaxation rates of the acids CH 3 COOD, CH 3 CD 2 COOD, and CD 3 CH 2 COOD dissolved in water (D 2 0) are presented and from these data simple acid-acid pair distribution functions are constructed. Association has been detected from excess intermolecular proton-proton interactions. In the solution of propionic acid the association is stronger as seen from the methylene group than from the methyl group.In the pure alcohols CD 3 0H and C 2 D 5 0H and their mixtures with inert solvents intermolecular proton relaxation is entirely of rotational character and permits conclusions concerning the depth of the potential characterizing the pair distribution function.

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“…Binding the Gd 3ϩ ion in this manner does result, however, in reduced relaxivity. Any polydentate ligand using all the Gd coordination sites would eliminate the inner sphere of influence totally and even ligands of modest size progressively reduce dipole-dipole interactions on a (1/ r)6 basis, as predicted by the Solomon-Bloembergen equations (39,40), though offsetting this effect is the fact that larger complexes rotate more slowly, which increases the interaction correlation time and efficacy.…”

Section: Gd Chelatesmentioning

confidence: 99%

Nephrogenic systemic fibrosis: Possible mechanisms and imaging management strategies

Dawson

2008

Magnetic Resonance Imaging

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Proton Relaxation Times in Paramagnetic Solutions

Cited by 1,006 publications

References 12 publications

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

Intermolecular nuclear relaxation and molecular pair distribution in liquid mixtures

Nephrogenic systemic fibrosis: Possible mechanisms and imaging management strategies

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