Publications by authors named "Caroline Robic"

Objectives: We aimed to evaluate gadopiclenol, a newly developed extracellular nonspecific macrocyclic gadolinium-based contrast agent (GBCA) having high relaxivity properties, which was designed to increase lesion detection and characterization by magnetic resonance imaging.

Methods: We described the molecular structure of gadopiclenol and measured the r1 and r2 relaxivity properties at fields of 0.47 and 1.

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An injectable purely apatitic calcium phosphate cement (CPC) was successfully combined to a water-soluble radiopaque agent (i.e., Xenetix ), to result in an optimized composition that was found to be as satisfactory as poly(methyl methacrylate) (PMMA) formulations used for vertebroplasty, in terms of radiopacity, texture and injectability.

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While not acutely toxic, chronic hepatic effect of certain gadolinium chelates (GC), used as contrast agent for magnetic resonance imaging, might represent a risk in renally-impaired patients due to free gadolinium accumulation in the liver. To answer this question, this study investigated the consequences of the presence of small amounts of either a soluble gadolinium salt ("free" Gd) or low-stability chelating impurity in the pharmaceutical solution of gadoteric acid, a macrocyclic GC with high thermodynamic and kinetic stabilities, were investigated in renally-impaired rats. Renal failure was induced by adding 0.

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Nephrogenic systemic fibrosis (NSF) is an iatrogenic scleroderma-like fibrosing systemic disorder occurring in patients with severe or end-stage renal disease. It was established as a new clinical entity in the year 2000. A causal role for gadolinium chelates (GC), widely used as contrast agents for magnetic resonance imaging, was suggested six years later.

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PEGylated polyester nanocapsules of perfluorooctyl bromide (PFOB) were surface-decorated with a RGD (arginine-glycine-aspartic acid) peptide by either pre-functionalization or post-functionalization strategies using carbodiimide-assisted chemistry. Both strategies allowed successful linkage of RGD at the surface of nanocapsules with up to 600-950 peptide units per nanocapsule without modifying the encapsulation efficacy of PFOB used as the (19)F MRI imaging moiety. Cryo-Transmission Electron Microscopy images evidence that slight changes of the polymer used to form the capsule shell strongly influence nanocapsule morphology.

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Molecular imaging with magnetic resonance imaging (MRI) targeted contrast agents has emerged as a promising diagnostic approach in cancer research to detect associated biomarkers. In this work, the potential of (19)F MRI was investigated to detect angiogenesis with α(ν)β(3)-targeted perfluorooctylbromide nanoparticles (PFOB NP) in a U87 glioblastoma mouse model at 7 Tesla. Mice were injected intravenously with targeted or non-targeted NP and (19)F images were immediately acquired for 90 min using a PFOB-dedicated MRI sequence.

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Delivery of therapeutic or diagnostic agents to the brain is majorly hindered by the blood-brain barrier (BBB). Recently, many studies have demonstrated local and transient disruption of the BBB using low power ultrasound sonication combined with intravascular microbubbles. However, BBB opening and closure mechanisms are poorly understood, especially the maximum gap that may be safely generated between endothelial cells and the duration of opening of the BBB.

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LipoCEST are liposome-encapsulating paramagnetic contrast agents (CA) based on chemical exchange saturation transfer with applications in biomolecular MRI. Their attractive features include biocompatibility, subnanomolar sensitivity, and amenability to functionalization for targeting biomarkers. We demonstrate MR imaging using a targeted lipoCEST, injected intravenously.

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A considerable increase in the saturation magnetization, M(s) (40%), and initial susceptibility of ultrasmall (<5 nm) iron oxide nanoparticles prepared by laser pyrolysis was obtained through an optimized acid treatment. Moreover, a significant enhancement in the colloidal properties, such as smaller aggregate sizes in aqueous media and increased surface charge densities, was found after this chemical protocol. The results are consistent with a reduction in nanoparticle surface disorder induced by a dissolution-recrystallization mechanism.

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We have recently developed an optimized multi-spin echo (MSE) sequence dedicated to perfluorooctyl bromide (PFOB) imaging yielding an excellent sensitivity in vitro. The aim of the present study was to apply this sequence to quantitative measurements in the mouse liver and spleen after intravenous (i.v.

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Nephrogenic systemic fibrosis (NSF), a disease occurring in patients with severe renal failure, may be linked to injections of gadolinium chelates, contrast agents used for magnetic resonance imaging. A hypothesis frequently proposed to explain NSF is dissociation of Gd(3+) from its chelate, possibly from a deep storage compartment. Numerous in vivo and in vitro studies have been performed in an attempt to determine the extent of this dechelation and to understand its mechanism.

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Objective: the purpose of this study was to compare the clinical, pathologic, and biochemical effects of repeated administrations of ionic macrocyclic or nonionic linear gadolinium chelates (GC) in rats with impaired renal function.

Material And Methods: rats submitted to subtotal nephrectomy were allocated to single injections of 2.5 mmol/kg of gadodiamide (nonionic linear chelate), nonformulated gadodiamide (ie, without the free ligand caldiamide), gadoterate (ionic macrocyclic chelate), or saline for 5 consecutive days.

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Lipid-containing nanostructures, in the form of solid lipid nanoparticles or iron oxide nanoparticles (NPs) coated with a lipid shell, were used as case studies for assessing and optimizing staining for transmission electron microscopy structural and compositional characterization. These systems are of paramount importance as drug delivery systems or as bio-compatible contrast agents. In particular, we have treated the systems with a negative (phospshotungstic acid) or with a positive (osmium tetroxide) staining agent.

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In the present work, the NMR properties of perfluorooctylbromide are revisited to derive a high-sensitivity fluorine MRI strategy. It is shown that the harmful effects of J-coupling can be eliminated by carefully choosing the bandwidth of the 180 degrees pulses in a spin-echo sequence. The T(2) of the CF(3) resonance of the molecule is measured using a multispin-echo sequence and shown to dramatically depend on the interpulse delay.

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In recent years there has been a renewed interest in the physicochemical properties of gadolinium chelates (GC). The aim of this review is to discuss the physicochemical properties of marketed GC with regard to possible biological consequences. GC can be classified according to three key molecular features: 1) the nature of the chelating moiety: either macrocyclic molecules in which Gd(3+) is caged in the preorganized cavity of the ligand, or linear, open-chain molecules; 2) ionicity: the ionicity of the molecule varies from neutral to tri-anionic agents; and 3) the presence or absence of an aromatic lipophilic moiety, which has a profound impact on the biodistribution of the GC.

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Colloidal dispersions of monodispersed and high-crystalline magnetite nanoparticles have been used to establish a relationship between magnetic properties and magnetic resonance (MR) relaxometric parameters in vitro. Magnetite nanoparticles with diameters between 4 and 14 nm were synthesized by thermal decomposition of Fe(acac)3 in different organic solvents and transformed to hydrophilic by changing oleic acid for dimercaptosuccinic acid (DMSA). A final treatment in alkaline water was critical to make the suspension stable at pH 7 with xi-potential values of -45 mV and hydrodynamic sizes as low as 50 nm.

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Gadolinium-based contrast agents are widely used to enhance image contrast in magnetic resonance imaging (MRI) procedures. Over recent years, there has been a renewed interest in the physicochemical properties of gadolinium chelates used as contrast agents for MRI procedures, as it has been suggested that dechelation of these molecules could be involved in the mechanism of a recently described disease, namely nephrogenic systemic fibrosis (NSF). The aim of this paper is to discuss the structure-physicochemical properties relationships of marketed gadolinium chelates in regards to their biological consequences.

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Ultrasmall superparamagnetic iron oxide (USPIO) particles are efficient contrast agents used in vivo to enhance relaxation differences between healthy and pathological tissues. Detailed understanding of their physicochemical properties in suspension is necessary to guarantee the quality and safety of biological USPIO particles application. The ferrofluids stability against aggregation and gravitational settling affects their biodistribution and consequently the resulting contrast.

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