title: Mn(II)-monosubstituted polyoxometalates as candidates for contrast agents in magnetic resonance imaging.
abstract: Two mono-substituted manganese polyoxometalates, K(6)MnSiW(11)O(39) (MnSiW(11)) and K(8)MnP(2)W(17)O(61) (MnP(2)W(17)), have been evaluated by in vivo and in vitro experiments as the candidates of potential tissue-specific contrast agents for magnetic resonance imaging (MRI). T1-relaxivities of 12.1mM(-1)s(-1) for MnSiW(11) and 4.7 mM(-1)s(-1) for MnP(2)W(17) (400 MHz, 25 degrees C) were higher than or similar to that of the commercial MRI contrast agent (GdDTPA). Their relaxivities in BSA and hTf solutions were also reported. After administration of MnSiW(11) and MnP(2)W(17) to Wistar rats, MR imaging showed longer and remarkable enhancement in rat liver and favorable renal excretion capability. The signal intensity increased by 74.0+/-4.9% for the liver during the whole imaging period (90 min) and by 67.2+/-5.3% for kidney within 20-70 min after injection at 40+/-3 micromol kg(-1) dose for MnSiW(11). MnP(2)W(17) induced 71.5+/-15.1% enhancement for the liver in 10-45 min range and 73.1+/-3.2% enhancement for kidney within 5-40 min after injection at 39+/-3 micromol kg(-1) dose. In vitro and in vivo study showed MnSiW(11) and MnP(2)W(17) being favorable candidates as the tissue-specific contrast agents for MRI.
authors.affiliation: Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Li
authors.forename: Weisheng
authors.initials: W
authors.lastname: Li
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Li
authors.forename: Fengkui
authors.initials: F
authors.lastname: Pei
authors.forename: Xuxia
authors.initials: X
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Lei
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D007668:Kidney / Q000000981:diagnostic imaging; D008099:Liver / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008345:Manganese / Q000737:chemistry*; D011877:Radionuclide Imaging; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D017973:Tungsten Compounds; D008345:Manganese