Use of Paramagnetic Chelated Metal Derivatives of Polysaccharides and Spin-Labeled Polysaccharides as Contrast Agents in Magnetic Resonance Imaging
| Autor: | J.A. Marriott, J. M. Pennock, I. A. Latham, S. W. A. Bligh, C. T. Harding, Graeme M. Bydder, J. D. Kelly, Peter J. Sadler, R. A. Bulman |
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| Rok vydání: | 1991 |
| Předmět: |
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Nitroxide mediated radical polymerization Magnetic Resonance Spectroscopy Free Radicals Starch Contrast Media Diamines Polysaccharide Cyclic N-Oxides chemistry.chemical_compound Polysaccharides Animals Organic chemistry Radiology Nuclear Medicine and imaging Chelation Cellulose Chelating Agents chemistry.chemical_classification Chemistry Electron Spin Resonance Spectroscopy Dextrans Nuclear magnetic resonance spectroscopy Hydrogen-Ion Concentration Pentetic Acid Ascorbic acid Magnetic Resonance Imaging Dextran Metals cardiovascular system Nitrogen Oxides Spin Labels Cyanogen bromide Rabbits circulatory and respiratory physiology Nuclear chemistry |
| Zdroj: | Magnetic Resonance in Medicine. 17:516-532 |
| ISSN: | 1522-2594 0740-3194 |
| Popis: | Soluble and insoluble polysaccharides were derivatized with diethylenetriaminepentaacetic acid (DTPA) and/or spin-labeled with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Polysaccharides derivatized with DTPA were prepared via cyanogen bromide activation, coupling to a diamine linker, and to DTPA anhydride. Spin-labeled polysaccharides were also prepared via cyanogen bromide activation. The extent of derivatization for dextran (18 kDa) was about 120 glucose units per DTPA, and for cellulose and starch about 15-30 units per DTPA. For spin-labeled polysaccharides, the average loading ranged from 1 nitroxide per 16 glucose units for starch to 181 for dextran (82 kDa). These derivatized paramagnetic polysaccharides were shown to be more effective relaxants than the small paramagnetic molecules alone. Both soluble and insoluble polysaccharide-linker-DTPA-Gd(III) complexes were effectively cleared from the body (rats) after oral administration. After intravenous administration, the biodistribution of dextran-linker-DTPA-Gd(III) complexes differed significantly from that of GdDTPA. Reduction of the nitroxide by ascorbic acid was retarded in the polysaccharide derivatives, particularly in starch derivatized with both nitroxide and linker-DTPA-Cu(II). These agents showed contrast enhancement in the gastrointestinal tract of rabbits. |
| Databáze: | OpenAIRE |
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