ISSN:
1352-8661
Keywords:
nitroxyl
;
contrast agent
;
dextran
;
arabinogalactan
;
EPR
;
relaxivity
;
molecular dynamics
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
,
Physics
Notes:
Abstract Synthetic methods are described leading to polysubstituted spin labeled polysaccharides (dextran 70, 110, 200, and arabinogalactan), which are potential contrast agents in magnetic resonance imaging. The nitroxyl moieties bound to a polysaccharide yield relaxivity enhanced by a factor of 1.6 (at 0.47 T and 37°C) compared to that of the small hydrophilic radicals. An EPR study at variable temperature and viscosity (by adding sucrose) reveals the presence of two mobile bound spin labels. The less mobile ones are characterized by an order parameterS≅0.6 and a macromolecular rotational correlation time of ∼1.6 ns at 20°C for the substituted dextrans. Substitution rate effects are observed and might be related to conformational changes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01709801
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