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Dynamic evaluation of the hepatic uptake and clearance of manganese‐based MRI contrast agents: A 31 P NMR study on the isolated and perfused rat liver
Author(s) -
Colet JeanMarie,
Elst Luce Vander,
Muller Robert N.
Publication year - 1998
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880080322
Subject(s) - manganese , contrast (vision) , mri contrast agent , medicine , hepatic diseases , chemistry , dynamic contrast enhanced mri , magnetic resonance imaging , perfusion , nuclear medicine , nuclear magnetic resonance , radiology , computer science , physics , organic chemistry , artificial intelligence
This spectroscopic study compares the mechanisms of the hepatic uptake of manganese chloride (MnCl 2 ) and manganese dipyridoxyl diphosphate (MnDPDP). Alterations of the phosphorus‐31 ( 31 P)‐NMR spectrum of the intracellular adenosine 5′‐triphosphate (ATP) are used to monitor the internalization of manganese by the isolated and perfused rat liver. Mn 2+ delivered as MnCl 2 in the perfusate rapidly enters the hepatocytes, where it strongly interacts with ATP, inducing a broadening of the 31 P lines. The inhibition of the process by nifedipine confirms that manganese ions cross the cellular membrane at least partly through Ca 2+ channels. MnDPDP induces weaker but still significant changes of the ATP spectrum. The inability of pyridoxine to compete for the uptake of manganese confirms that the vitamin B 6 carrier is not involved in the internalization process of the paramagnetic complex. Finally, preincubation of MnDPDP with blood does not increase the extent of the dissociation. The alterations of the 31 P spectrum of the liver subsequent to the administration of MnDPDP are attributable to a fraction of free Mn 2+ released by the chelate and delivered to the hepatocytes.