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Titolo:
NEW MULTIMERIC MAGNETIC-RESONANCE-IMAGING AGENTS
Autore:
RANGANATHAN RS; FERNANDEZ ME; KANG SI; NUNN AD; RATSEP PC; PILLAI KMR; ZHANG X; TWEEDLE MF;
Indirizzi:
BRACCO RES USA INC,305 COLL RD E PRINCETON NJ 08540 WARNER LAMBERT PARKE DAVIS MORRIS PLAINS NJ 07950 HENKEL CORP AMBLER PA 00000 SHIMADZU INSTRUMENTS PRINCETON NJ 00000 PFIZER INC GROTON CT 06340
Titolo Testata:
Investigative radiology
fascicolo: 11, volume: 33, anno: 1998,
pagine: 779 - 797
SICI:
0020-9996(1998)33:11<779:NMMA>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
WATER EXCHANGE; GADOLINIUM(III) COMPLEXES; AMINO CARBOXYLATES; HYDRATION NUMBERS; CONTRAST AGENTS; PH-DEPENDENCE; O-17 NMR; RELAXATION; RELAXIVITIES;
Keywords:
MRI CONTRAST AGENTS; GD CHELATES; MULTIMERS; WATER RELAXATION TIME;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
R.S. Ranganathan et al., "NEW MULTIMERIC MAGNETIC-RESONANCE-IMAGING AGENTS", Investigative radiology, 33(11), 1998, pp. 779-797

Abstract

RATIONALE AND OBJECTIVES. The authors investigated the effect of multimerization on the relaxivity of macrocyclic gadolinium (Gd) chelates,The objective was to develop more sensitive magnetic resonance imaging (MRI) contrast agents to study biochemical processes. METHODS. Covalently linked nonionic, macrocyclic, multimeric lanthanide chelates that belong to the classes of dimers, trimers, tetramers, hexamer, and octamer, in the molecular weight range similar to 1 to 5 KDa, were synthesized. The chemical linkage was based on either the a;nide bond or the 2-hydroxypropylidene bond. Relaxivity values, (20)r(1), on Gd3+ chelates and hydration numbers, Q, on Tb3+ chelates were determined. RESULTS. Relaxivity values increased with molecular weight and Q values were not affected. the increase in r(1) is attributable to the expected increase in the overall rotational correlation time, tau(r) with an increase in molecular weight. The rigidity of the linkers, which is expected to affect the intrachelate rotational: correlation time tau(r) that makes a contribution to the overall correlation time, tau(r), exerted a noticeable effect. The hydroxyl-based chelates generally had lower r(1) values than the amide-based chelates, This is rationalized as arising from the longer and thereby rate-limiting effect of the tau(m) value for the hydroxyl chelates compared with that reported of the amide-based chelates, This rate limiting effect of tau(m) becomes a dominant factor controlling attainable enhanced relaxivity when multimers based on traditional chelate designs are used for MRI applications. CONCLUSIONS. Approaches aimed at enhancing relaxivity by modulating the water relaxation time, tau(m), will be important for the future development of functional MRI contrast agents for the imaging of biochemical processes.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/04/20 alle ore 11:45:12