Liver-directed superparamagnetic iron oxide: Quantitation of T2 relaxation effects

Pouliquen, Daniel; Lucet, I.; Chouly, C.; Perdrisot, Rémy; Jeune, J. J. Le; Jallet, P.

doi:10.1016/0730-725x(93)90026-a

Cited by 28 publications

(14 citation statements)

References 11 publications

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“…The monoexponential decay (Eq. [46]) is in agreement with experimental findings (34)(35)(36). The relaxation rate is directly proportional to the bone volume fraction (s) and magnetic field (B,), but initial signal amplitude, S(O), decreases with bone volume fraction as (1 -s).…”

Section: Asymmetrical (Isotropicalsupporting

confidence: 87%

Theory of NMR signal behavior in magnetically inhomogeneous tissues: The static dephasing regime

Yablonskiy

Haacke

1994

Magnetic Resonance in Med

1,112

1,525

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This paper is devoted to a theory of the NMR signal behavior in biological tissues in the presence of static magnetic field inhomogeneities. We have developed an approach that analytically describes the NMR signal in the static dephasing regime where diffusion phenomena may be ignored. This approach has been applied to evaluate the NMR signal in the presence of a blood vessel network (with an application to functional imaging), bone marrow (for two specific trabecular structures, asymmetrical and columnar) and a ferrite contrast agent. All investigated systems have some common behavior. If the echo time TE is less than a known characteristic time tc for a given system, then the signal decays exponentially with an argument which depends quadratically on TE. This is equivalent to an R2* relaxation rate which is a linear function of TE. In the opposite case, when TE is greater than tc, the NMR signal follows a simple exponential decay and the relaxation rate does not depend on the echo time. For this time interval, R2* is a linear function of a) volume fraction sigma occupied by the field-creating objects, b) magnetic field Bo or just the objects' magnetic moment for ferrite particles, and c) susceptibility difference delta chi between the objects and the medium.

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Section: Asymmetrical (Isotropicalsupporting

confidence: 87%

Theory of NMR signal behavior in magnetically inhomogeneous tissues: The static dephasing regime

Yablonskiy

Haacke

1994

Magnetic Resonance in Med

1,112

1,525

View full text Add to dashboard Cite

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“…The biodistribution and circulation time of contrast agents is determined by several factors such as size, charge, and surface chemistry [23,24,63]. Nanoparticles of hydrodynamnic size greater than 50 nm, and hydrophilic surface and high charges are eliminated from the circulation within minutes by phagocytotic cells of the RES.…”

Section: Discussionmentioning

confidence: 99%

“…SPIONs have important advantages over gadolinium chelates: they have low toxicity; in some instances toxicities were reported at concentrations more than 100-fold above the clinically effective dosage [21] and their detection limit in MRI is in the subnanomolar range exceeded Gd imaging by a factor of 100 [22]. The biodistribution of nanoparticulate contrastagents is determined by factors including size, charge and surface chemistry [23,24]. Administered systemically, unconjugated nanoparticles accumulate in liver, spleen, and bone marrow, all of which are dependent on the reticulo endothelial system (RES).…”

Section: Introductionmentioning

confidence: 99%

LHRH-conjugated Magnetic Iron Oxide Nanoparticles for Detection of Breast Cancer Metastases

Leuschner

Kumar

Hansel

et al. 2006

Breast Cancer Res Treat

159

114

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Targeted delivery of superparamagnetic iron oxide nanoparticles (SPIONs) could facilitate their accumulation in metastatic cancer cells in peripheral tissues, lymph nodes and bones and enhance the sensitivity of magnetic resonance imaging (MRI). The specificities of luteinizing hormone releasing hormone (LHRH) and luteinizing hormone/chorionic gonadotropin (LH/CG)- bound SPIONs were tested in human breast cancer cells in vitro and were found to be dependent on the receptor expression of the target cells, the time of incubation and showed saturation kinetics. In incubations with MDA-MB-435S.luc cells, the highest iron accumulation was 452.6 pg Fe/cell with LHRH-SPIONs, 203.6 pg Fe/cell with beta-CG-SPIONs and 51.3 pg Fe/cell with SPIONs. Incubations at 4 degrees C resulted in 1.1 pg Fe/cell. Co-incubation with the same ligands (betaCG or LHRH) decreased the iron accumulation in each case. LHRH-SPIONs were poorly incorporated by macrophages. Tumors and metastatic cells from breast cancer xenografts were targeted in vivo in a nude mouse model. LHRH-SPION specifically accumulated in cells of human breast cancer xenografts. The amount of LHRH-SPION in the lungs was directly dependent on the number of metastatic cells and amounted to 77.8 pg Fe/metastastic cell. In contrast, unconjugated SPIONs accumulated in the liver, showed poor affinity to the tumor, and were not detectable in metastatic lesions in the lungs. LHRH-SPION accumulated in the cytosolic compartment of the target cells and formed clusters. LHRH-SPIONs did not accumulate in livers of normal mice. In conclusion, LHRH conjugated SPIONs may serve as a contrast agent for MR imaging in vivo and increase the sensitivity for the detection of metastases and disseminated cells in lymph nodes, bones and peripheral organs.

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“…Although the liver rapidly fixes approximately 50% of the ID, the biodistributions obtained for particles coated with our bisphosphonates are different from those of dextran-coated particles such as MD [Pouliquen et al, 1993;Chouly et al, 1996;Rousseau, 1996] or commercial ones (AMI 25, AMI 227). The capture by the liver of particles coated with bisphosphonates is very fast but tends to remain stable with time.…”

Section: Discussionmentioning

confidence: 98%

“…Hydrophilic polymer corona like dextran lead to large particle diameters, often with rapid clearance by the Mononuclear Phagocyte System (MPS) [Saini et al, 1987;Weissleder et al, 1988]. Many assays have tried to modify the biodistribution: for example, to decrease the superficial layer thickness, polymer sizes have been reduced by enzymatic degradation [Chouly et al, 1996] or by oxidation [Pouliquen et al, 1993]. Another type of study looks to target other organs or tissues by covalently grafted antibodies [Weissleder et al, 1991] or specific peptides [Josephson et al, 1999], but modification of the initial polymers often induces a great capture by the hepatosplenic system.…”

Section: Introductionmentioning

confidence: 99%

Comparative biodistribution of thin‐coated iron oxide nanoparticles TCION: Effect of different bisphosphonate coatings

Portet

Denizot

Rump³

et al. 2001

Drug Development Research

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Because the nature of their coatings influences the biodistribution of nanocolloids, five different bisphosphonates bearing OH, NH 2 , NMe 2 , and N+Me 3 groups were evaluated in vivo. Tc-labeled nanoparticles biodistribution. The different coatings do not change hydrodynamic radius (∼12 nm) and relaxivities. The negative surface charge is half for particles coated with bisphosphonates bearing quaternary ammonium compared to those bearing a hydroxyl function. Nanoparticle vascular initial half disappearance time range between 25 and 39 min, with hepatic capture between 50 and 80% ID at 18 h. Bones and muscles fix globally around 35 % ID at 18 h, with high concentrations in the mineral bones. Hydroxy-bisphosphonates and quaternary ammonium-bisphosphonate-coated nanoparticles are the most efficient for blood remanence, weak liver capture, and bone targeting. Drug Dev.

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Liver-directed superparamagnetic iron oxide: Quantitation of T2 relaxation effects

Cited by 28 publications

References 11 publications

Theory of NMR signal behavior in magnetically inhomogeneous tissues: The static dephasing regime

Theory of NMR signal behavior in magnetically inhomogeneous tissues: The static dephasing regime

LHRH-conjugated Magnetic Iron Oxide Nanoparticles for Detection of Breast Cancer Metastases

Comparative biodistribution of thin‐coated iron oxide nanoparticles TCION: Effect of different bisphosphonate coatings

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