Spin labelled arabinogalactan as MRI contrast agent

Gallez, Bernard; Lacour, Valérie; Demeure, Roger; Debuyst, René; Dejehet, Fernand; Keyser, J.-L. De; Dumont, Pierre

doi:10.1016/0730-725x(94)92353-1

Cited by 44 publications

(24 citation statements)

References 33 publications

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“…143 Moreover, nitroxides can be linked to carrier molecules to achieve a tissue or organ selectivity. 144,145 The effect of oxygen on the linewidths of these compounds is fairly modest but may be sufficient for several applications. When the concentration of oxygen increases from 0 to 210 mM (the concentration of oxygen in a physiological solution in equilibrium with air), the EPR linewidth increases by approximately 100 mGauss.…”

Section: Soluble Paramagnetic Materialsmentioning

confidence: 99%

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

2004

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This review paper attempts to provide an overview of the principles and techniques that are often termed electron paramagnetic resonance (EPR) oximetry. The paper discusses the potential of such methods and illustrates they have been successfully applied to measure oxygen tension, an essential parameter of the tumor microenvironment. To help the reader understand the motivation for carrying out these measurements, the importance of tumor hypoxia is first discussed: the basic issues of why a tumor is hypoxic, why these hypoxic microenvironments promote processes driving malignant progression and why hypoxia dramatically influences the response of tumors to cytotoxic treatments will be explained. The different methods that have been used to estimate the oxygenation in tumors will be reviewed. To introduce the basics of EPR oximetry, the specificity of in vivo EPR will be discussed by comparing this technique with NMR and MRI. The different types of paramagnetic oxygen sensors will be presented, as well as the methods for recording the information (EPR spectroscopy, EPR imaging, dynamic nuclear polarization). Several applications of EPR for characterizing tumor oxygenation will be illustrated, with a special emphasis on pharmacological interventions that modulate the tumor microenvironment. Finally, the challenges for transposing the method into the clinic will also be discussed.

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Section: Soluble Paramagnetic Materialsmentioning

confidence: 99%

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

2004

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“…Macromolecular: a Gd-DTPA conjugate of polylysine (PL) derivatized with galactosyl groups (Gd-DTPA-gal-PL) [24] and a spin-labeled arabinogalactan [25];…”

Section: Ln-chelate Glycoconjugates As Molecular Imaging Casmentioning

confidence: 99%

Glycoconjugate Probes and Targets for Molecular Imaging Using Magnetic Resonance

2010

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Review Molecular recognition of sugar residues applied in molecular imagingMolecular imaging aims at probing the molecular abnormalities that are the basis of diseases rather than to image their effects [1]. An important prerequisite of this approach is the selection of appropriate markers of disease and of targeting vectors to recognize them. The latter can include low-molecular weight substrates for enzymes or high-molecular weight affinity ligands, such as monoclonal antibodies, hormone analogs and recombinant proteins. Of the three major classes of biomolecules (proteins, nucleic acids and carbohydrates), the latter class is the least exploited in molecular imaging. However, a dense layer of glyco conjugates covers all cells and carbohydrate mediated cellular recognition plays an important role in nature, both in normal and malignant processes, such as cell-cell communication, infection, inflammation, metastasis and reproduction. As carriers of information, the carbohydrates have far greater potential than proteins and nucleic acids; three different nucleotides or amino acids can generate only six distinguishable structures, while over 1000 structures can be built up from three different monosaccharides [2]. This level of complexity is probably the reason for the fact that the exploration of these compounds in molecular imaging is lagging behind [3]. Recently, significant progress has been made in glycochemistry and glycobiology; for example, automated solid-phase synthesis of oligo saccharides has become possible [4], carbohydrate-based vaccines have been developed [5] and high-throughput methods have been designed for the screening of molecular interactions [6]. The exciting new developments in glycoscience are opening way for new challenges in exploring the full potential of carbohydrates in molecular imaging. Therefore, here we give an overview of the recent literature on the use of glycoconjugates either as probes or targets in molecular imaging using MRI.MRI contrast agents (CAs) are broadly described as positive or negative, depending on whether they give rise to a brightening or a darkening effect on the MR image, respectively. The positive or brightening effect predominantly relates to the longitudinal proton relaxation time (T 1 ) and the negative or darkening effect predominantly relates to the transverse proton relaxation time (T 2 ). To date, the majority of commercially available and clinically applied positive CAs are Gd 3+ complexes of the polyaminocarboxylates diethylene triamine pentacetic acid (DTPA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) (see FiguRe 1 for some typical examples) and negative CAs are various iron oxide particles. These agents are not actively targeting. The targeted CAs for application in molecular imaging that are currently under development and described below are generally based on compounds 1 (Gd-DTPA) and 2 (Gd-DOTA), as well as iron oxide nanoparticles.Glycoconjugate probes and targets for molecular imaging using magnetic resonanceRecently...

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“…[27] 99m Tc-DTPA-GSA, a conjugate of galactosylated serum albumin (GSA) with 99m Tc-DTPA (DTPA = 3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid), is useful in SPECT (single photon emission computed tomography) hepatic imaging to assess ASGPR in mice [28] and used clinically in humans. [29,30] Monocrystalline iron oxide nanoparticles (MION) conjugated to the bovine plasma protein asialofetuin (ASF), (MION-ASF), [31] arabinogalactan (AG)-coated ultra-small superparamagnetic iron oxide particles (USPIO), (AG-USPIO), [32,33] spin-labelled arabinogalactan, [34] and a Gd-DTPA conjugate of polylysine (PL) derivatized with galactosyl groups (Gd-DTPA-gal-PL), [35] have also been developed as potential contrast agents for liver MRI by targeting the hepatocyte ASGPR and tested in cells and mice. [36] The covalent binding of Gd III chelates to macro and biomolecules [7,8] and the formation of supramolecular assemblies [15] have been reported to slow down the tumbling rate of the paramagnetic chelates which leads then to higher relaxivities.…”

Section: Magnetic Resonance Imaging (Mri) Is a Diagnostic Modalitymentioning

confidence: 99%

Lanthanide(III) Complexes of DOTA–Glycoconjugates: A Potential New Class of Lectin‐Mediated Medical Imaging Agents

André

Geraldes

Martins

et al. 2004

Chemistry A European J

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Spin labelled arabinogalactan as MRI contrast agent

Cited by 44 publications

References 33 publications

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

Glycoconjugate Probes and Targets for Molecular Imaging Using Magnetic Resonance

Lanthanide(III) Complexes of DOTA–Glycoconjugates: A Potential New Class of Lectin‐Mediated Medical Imaging Agents

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