Publications de Arnaud Comment

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Lithium is widely used in psychotherapy. The Li-6 isotope has a long intrinsic longitudinal relaxation time T-1 on the order of minutes, making it an ideal candidate for hyperpolarization experiments. In the present study we demonstrated that lithium-6 can ...

Glucose is the primary source of energy for the brain but also an important source of building blocks for proteins, lipids, and nucleic acids. Little is known about the use of glucose for biosynthesis in tissues at the cellular level. We demonstrate that l ...

Dissolution dynamic nuclear polarization (DNP) provides a way to tremendously improve the sensitivity of nuclear magnetic resonance experiments. Once the spins are hyperpolarized by dissolution DNP, the radicals used as polarizing agents become undesirable ...

A major challenge in cancer biology is to monitor and understand cancer metabolism in vivo with the goal of improved diagnosis and perhaps therapy. Because of the complexity of biochemical pathways, tracer methods are required for detecting specific enzyme ...

We performed an Eu153 and Eu151 NMR study of EuO and Gd doped EuO using a home-made spectrometer designed to measure signals with fast spin-spin relaxation times. We determined and described the broadening mechanisms giving rise to the structure in the lineshape of pure EuO. The complete description of the lineshape of pure EuO allowed us to highlight the influence of doping EuO with Gd impurities on the lineshape. We demonstrated the presence of a temperature dependent static magnetic inhomogeneity in Gd d

The increase of total choline in tumors has become an important biomarker in cancer diagnosis. Choline and choline metabolites can be measured in vivo and in vitro using multinuclear MRS. Recent in vivo C-13 MRS studies using labeled substrates enhanced vi ...

The γ-glutamyl transpeptidase (GGT) enzyme plays a central role in glutathione homeostasis. Direct detection of GGT activity could provide critical information for the diagnosis of several pathologies. We propose a new molecular probe, γ-Glu-[1-(13) C]Gly, ...

We report results of muon-spin-rotation measurements performed on the ferromagnetic semiconductor EuO, which is one of the best approximations to a localized ferromagnet. We argue that implanted muons are sensitive to the internal field primarily through a combination of hyperfine and Lorentz fields. The temperature dependences of the internal field and the relaxation rate have been measured and are compared with previous theoretical predictions.

An Eu NMR study in the ferromagnetic phase of pure and Gd-doped EuO was performed. A complete description of the NMR line shape of pure EuO allowed for the influence of doping EuO with Gd impurities to be highlighted. The presence of a temperature-dependen ...

Hyperpolarized 2-keto[1-13C]isocaproate (KIC) provides a means to probe brain nitrogen homeostasis and to assess molecular signatures of tumors. The dynamic nuclear polarization process requires a free-radical polarizing agent, and samples are typically doped with persistent radicals. An alternative is to use photo-induced radicals of α-keto acids that recombine upon dissolution. [1-13C]KIC hyperpolarized with photo-induced radicals could be used to measure the alterations in amino acid metabolism that are

We describe a low-temperature thermodynamic model for dynamic nuclear polarization (DNP) via continuous-wave partial saturation of electron spin resonance (ESR) lines that are both homogeneously and inhomogeneously broadened. It is a variant of a reasoning ...

Various tumors develop addiction to glutamine to support uncontrolled cell proliferation. Here we identify the nuclear receptor liver receptor homolog 1 (LRH-1) as a key regulator in the process of hepatic tumorigenesis through the coordination of a noncan ...

Ex vivo and in vivo studies on liver metabolism using hyperpolarized [1-13C]pyruvate report do not agree on whether hyperpolarized bicarbonate metabolite production results from pyruvate oxidation or gluconeogenesis. This study tested the ability of hyperpolarized [1-13C]pyruvate to probe gluconeogenesis in the liver of intact rats. While conversion to hyperpolarized bicarbonate was detected in the liver of fasted rats, treatment with the phosphoenolpyruvate carboxykinase inhibitor 3-mercaptopicolinc acid r

In vivo localized and fully adiabatic homonuclear and heteronuclear polarization transfer experiments were designed and performed in the rat brain at 9.4 T after infusion of hyperpolarized sodium [1,2-(13) C(2) ] and sodium [1-(13) C] acetate. The method p ...

[1-C-13]pyruvate is the most widely used hyperpolarized metabolic magnetic resonance imaging agent. Using a custom-built 7.0 T polarizer operating at 1.0 K and trityl radical-doped [1-C-13] pyruvic acid, unextrapolated solution-state C-13 polarization grea ...

In developing an intact rat model for myocardial ischemia using hyperpolarized 13C pyruvate, different compound formulations were evaluated. Infusion of 4-hydroxy-TEMPO-polarized sodium [1-13C]pyruvate was compared to an equivalent dose of buffered trityl radical-polarized [1-13C]pyruvic acid. Whereas higher levels of polarization and MRS signal were obtained with trityl radical, the metabolite signals normalized to total signal were lower. In particular, [1-13C]lactate signal relative to total signal was m

Vitamin C for longer lifetimes: N-oxide radicals that are widely used for dynamic nuclear polarization can be reduced by scavengers such as sodium ascorbate (vitamin C) during the dissolution process, thus diminishing losses of polarization during the tran ...

An essential feature of magnetic resonance (MR) probes for magnetic resonance imaging and spectroscopy is the ability to generate uniform B-1(+) excitation in a volume of interest. When the magnetic field strength is increased, leading to an increase in re ...

Hyperpolarized magnetic resonance via dissolution dynamic nuclear polarization necessitates the transfer of the hyperpolarized molecules from the polarizer to the imager prior to in vivo measurements. This process leads to unavoidable losses in nuclear pol ...

Arnaud Comment

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Hyperpolarized Lithium-6 as a Sensor of Nanomolar Contrast Agents

Imaging the time-integrated cerebral metabolic activity with subcellular resolution through nanometer-scale detection of biosynthetic products deriving from (13)C-glucose

Producing Radical-Free Hyperpolarized Perfusion Agents for In Vivo Magnetic Resonance Using Spin-Labeled Thermoresponsive Hydrogel

Analysis of Cancer Metabolism by Imaging Hyperpolarized Nuclei: Prospects for Translation to Clinical Research

Study of pure and gadolinium doped single crystals of europium monoxide by nuclear magnetic resonance

Feasibility of in vivo N-15 MRS detection of hyperpolarized N-15 labeled choline in rats

Direct Monitoring of γ-Glutamyl Transpeptidase Activity In Vivo Using a Hyperpolarized (13) C-Labeled Molecular Probe

Phase transition in the localized ferromagnet EuO probed by μSR

Magnetic properties of pure and Gd-doped EuO probed by NMR

Hyperpolarized acetate as a metabolic tracer for skeletal and cardiac muscle energetics

Hyperpolarization of 2-keto[1-13C]isocaproate for in vivo studies with photo-induced radicals

Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation

LRH-1-dependent programming of mitochondrial glutamine processing drives liver cancer

Effects of 3-MPA on in vivo hepatic metabolism of hyperpolarized [1-13C] pyruvate

Localized in vivo hyperpolarization transfer sequences

High-field dissolution dynamic nuclear polarization of [1-C-13]pyruvic acid

The formulation of hyperpolarized 13C pyruvate solutions influences the labeling of myocardial metabolites in vivo

Scavenging Free Radicals To Preserve Enhancement and Extend Relaxation Times in NMR using Dynamic Nuclear Polarization

Ultra-High Field Birdcage Coils: a Comparison Study at 14.1T

Automated transfer and injection of hyperpolarized molecules with polarization measurement prior to in vivo NMR