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721 results on '"Babonneau, Florence"'

6. Confining calcium oxalate crystal growth in a carbonated apatite-coated microfluidic channel to better understand the role of Randall's plaque in kidney stone formation.

Author

Bourg, Samantha, Rakotozandriny, Karol, Lucas, Ivan T., Letavernier, Emmanuel, Bonhomme, Christian, Babonneau, Florence, and Abou-Hassan, Ali

Subjects
CALCIUM oxalate, KIDNEY stones, CRYSTAL growth, CALCIUM ions, HYDROXYAPATITE coating, CALCITE crystals, SUPERSATURATED solutions, LAMINAR flow
Abstract

Effective prevention of recurrent kidney stone disease requires the understanding of the mechanisms of its formation. Numerous in vivo observations have demonstrated that a large number of pathological calcium oxalate kidney stones develop on an apatitic calcium phosphate deposit, known as Randall's plaque. In an attempt to understand the role of the inorganic hydroxyapatite phase in the formation and habits of calcium oxalates, we confined their growth under dynamic physicochemical and flow conditions in a reversible microfluidic channel coated with hydroxyapatite. Using multi-scale characterization techniques including scanning electron and Raman microscopy, we showed the successful formation of carbonated hydroxyapatite as found in Randall's plaque. This was possible due to a new two-step flow seed-mediated growth strategy which allowed us to coat the channel with carbonated hydroxyapatite. Precipitation of calcium oxalates under laminar flow from supersaturated solutions of oxalate and calcium ions showed that the formation of crystals is a substrate and time dependent complex process where diffusion of oxalate ions to the surface of carbonated hydroxyapatite and the solubility of the latter are among the most important steps for the formation of calcium oxalate crystals. Indeed when an oxalate solution was flushed for 24 h, dissolution of the apatite layer and formation of calcium carbonate calcite crystals occurred which seems to promote calcium oxalate crystal formation. Such a growth route has never been observed in vivo in the context of kidney stones. Under our experimental conditions, our results do not show any direct promoting role of carbonated hydroxyapatite in the formation of calcium oxalate crystals, consolidating therefore the important role that macromolecules can play in the process of nucleation and growth of calcium oxalate crystals on Randall's plaque. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Investigation of Carbonate Substitution in Hydroxyapatite by Combining Solid‐state NMR and DFT Calculations.

Author

Su, Yangyang, Brigiano, Flavio Siro, Petit, Ivan, Leroy, César, Bonhomme, Christian, Babonneau, Florence, Tielens, Frederik, and Gervais, Christel

Subjects
HYDROXYAPATITE, CHEMICAL energy, SUBSTANCE abuse, APATITE
Abstract

Biological apatites (main constituent of natural bones) correspond to non‐stoichiometric hydroxyapatite HAp, presenting a large variety of ions as substituents (CO32−, F−, SiO44−, Mg2+, Na+...). The precise location and configuration of ionic substitutes in the HAp matrix are generally difficult to identify and characterize. This contribution details the structural characterization based on NMR data of a particular case of hydroxyapatite substitution by carbonates. For this purpose, all substitution mechanisms proposed to our knowledge in the literature are modeled by DFT and the corresponding calculated NMR parameters allowed to propose or confirm some interpretations of a certain number of experimental observations to rationalize the dependencies of the 13C chemical shift and energy on these structural parameters. The presented results open the way for a fast interpretation of 13C NMR experiments on defective HAp materials and will allow to predict the most stable arrangement of CO32− for a given family of defects. [ABSTRACT FROM AUTHOR]

Published
2023
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27. A novel multinuclear solid-state NMR approach for the characterization of kidney stones

Author

Leroy, César, Bonhomme-Coury, Laure, Gervais, Christel, Tielens, Frederik, Babonneau, Florence, Daudon, Michel, Bazin, Dominique, Letavernier, Emmanuel, Laurencin, Danielle, Iuga, Dinu, Hanna, John V., Smith, Mark, and Bonhomme, Christian

Subjects
QD, RC
Abstract

The spectroscopic study of pathological calcifications (including kidney stones) is extremely rich and helps to improve the understanding of the physical and chemical processes associated with their formation. While Fourier transform infrared (FTIR) imaging and optical/electron microscopies are routine techniques in hospitals, there has been a dearth of solid-state NMR studies introduced into this area of medical research, probably due to the scarcity of this analytical technique in hospital facilities. This work introduces effective multinuclear and multidimensional solid-state NMR methodologies to study the complex chemical and structural properties characterizing kidney stone composition. As a basis for comparison, three hydrates (n=1, 2 and 3) of calcium oxalate are examined along with nine representative kidney stones. The multinuclear magic angle spinning (MAS) NMR approach adopted investigates the 1H, 13C, 31P and 31P nuclei, with the 1H and 13C MAS NMR data able to be readily deconvoluted into the constituent elements associated with the different oxalates and organics present. For the first time, the full interpretation of highly resolved 1H NMR spectra is presented for the three hydrates, based on the structure and local dynamics. The corresponding 31P MAS NMR data indicates the presence of low-level inorganic phosphate species; however, the complexity of these data make the precise identification of the phases difficult to assign. This work provides physicians, urologists and nephrologists with additional avenues of spectroscopic investigation to interrogate this complex medical dilemma that requires real, multitechnique approaches to generate effective outcomes.

Published
2021

41. A novel multinuclear solid state NMR approach for the characterization of kidney stones

Author

Leroy, César, primary, Bonhomme-Coury, Laure, additional, Gervais, Christel, additional, Tielens, Frederik, additional, Babonneau, Florence, additional, Daudon, Michel, additional, Bazin, Dominique, additional, Letavernier, Emmanuel, additional, Laurencin, Danielle, additional, Iuga, Dinu, additional, Hanna, John Vincent, additional, Smith, Mark Edmund, additional, and Bonhomme, Christian, additional

Published
2021
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