Biomimetic nanocrystalline apatites: Emerging perspectives in cancer diagnosis and treatment

Nanocrystalline calcium phosphate apatites constitute the mineral part of hard tissues, and the synthesis of biomimetic analogs is now wellmastered at the labscale. Recent advances in the fine physicochemical characterization of these phases enable one to envision original applications in the medical field along with a better understanding of the underlying chemistry and related pharmacological features. In this contribution, we specifically focused on applications of biomimetic apatites in the field of cancer diagnosis or treatment. We first report on the production and first biological evaluations (cytotoxicity, proinflammatory potential, internalization by ZR751 breast cancer cells) of individualized luminescent nanoparticles based on Eudoped apatites, eventually associated with folic acid, for medical imaging purposes. We then detail, in a first approach, the preparation of tridimensional constructs associating nanocrystalline apatite aqueous gels and drugloaded pectin microspheres. Sustained releases of a fluorescein analog (erythrosin) used as model molecule were obtained over 7 days, in comparison with the ceramic or microsphere reference compounds. Such systems could constitute original bonefilling materials for in situ delivery of anticancer drug

Interaction entre le cytochrome c552 de la bactérie Thermus Thermophilus et des modèles de son partenaire oxydant (étude du processus de transfert d'électron par spectrométries de vibration et électrochimie)

LIMOGES-ENSCI (870852305) / SudocPARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Promouvoir l'introduction d'une alimentation diversifiée en morceaux : étude qualitative de l'effet d'une intervention

National audienceLa diversification alimentaire, période clé de formation des habitudes alimentaires, permet à l'enfant de découvrir de nouveaux goûts et textures. L'introduction d'aliments texturés est recommandée entre 8 et 10 mois pour tendre vers l'alimentation familiale. Des données récentes montrent qu'en France une majorité d'enfants reçoit une alimentation principalement mixée jusqu'à 12 mois. Cette étude qualitative vise à comprendre les effets d'une étude interventionnelle favorisant l'introduction des textures dans l'alimentation des enfants entre 8 et 15 mois. Soixante enfants ont participé à cette étude. Leur comportement envers différentes textures a été évalué au laboratoire à 8 et 15 mois. La moitié des parents (groupe intervention) a bénéficié de recommandations sur l'introduction des textures et d'un suivi mensuel personnalisé. A l'issue de l'étude, 16 parents de chaque groupe ont été interrogés (entretien semi-directif) quant à l'évolution de la diversification alimentaire lors de la première année et leur ressenti concernant l'introduction des textures. L'introduction des textures a également été décrite grâce à un jeu d'images (ex : purée, petits morceaux) afin de mettre en évidence d'éventuelles dissonances avec le discours. Peu de différences ont été mises en évidence entre les verbatim et les résultats du jeu d'images. Alors même qu'ils craignaient leur introduction, les parents ayant reçu des recommandations (n=16) ont proposé des aliments de différentes textures plus rapidement que ceux n'en ayant pas reçu. Par ailleurs, quel que soit le groupe, les venues au laboratoire à 8 mois ont rassuré la moitié des parents quant à l'introduction des textures à la maison

A novel cryo-reduction method to investigate the molecular mechanism of nitric oxide synthases

International audienceNitric oxide synthases (NOSs) are hemoproteins responsible for the biosynthesis of NO in mammals. They catalyze two successive oxidation reactions. The mechanism of oxygen activation is based on the transfer of two electrons and two protons. Despite structural analogies with cytochromes P450, the molecular mechanism of NOS remains yet to be elucidated. Because of extremely high reaction rates, conventional kinetics methods failed to trap and characterize the major reaction intermediates. Cryo-reduction methods offer a possibility to circumvent this technological lock, by triggering oxygen activation at cryogenic temperatures by using water radiolysis. However, this method is not adapted to the NOS mechanism because of the high instability of the initial Fe(II)O2 complex (extremely fast autoxidation and/or reaction with the cofactor H4B). This imposed a protocol with a stable Fe(II)O2 complex (observed only for one NOS-like protein) and that excludes any redox role for H4B. A relevant approach to the NOS mechanism would use H4B to provide the (second) electron involved in oxygen activation; water radiolysis would thus provide the first electron (heme reduction). In this context, we report here an investigation of the first electron transfer by this alternative approach, i.e., the reduction of native NOS by water radiolysis. We combined EPR and resonance Raman spectroscopies to analyze NOS reduction for a combination of different substrates, cofactor, and oxygen concentrations, and for different NOS isoforms. Our results show that cryo-reduction of native NOS is achieved for all conditions that are relevant to the investigation of the NOS mechanism

Impact of A90P, F106L and H64V mutations on neuroglobin stability and ligand binding kinetics

International audienc

Fostering infant food texture acceptance: A pilot intervention promoting food texture introduction between 8 and 15 months

International audienceHealthy infant feeding practices form the basis of healthy eating behaviour later in life. The effect of providing parents with recommendations on textured food introduction between 8 and 15 months on children's experience with and acceptance of textured foods was studied. Sixty parent/child dyads were randomly assigned to a control group (CG) receiving current French recommendations and an intervention group (IG) receiving a brochure with supplementary advice, tips and monthly counselling on food texture introduction. After the intervention, parents completed self-report measures about the introduction of 188 food items, including purees, soft/small pieces, hard/large pieces and double textures. Children's acceptance of eight textured foods was assessed in a laboratory setting. Parents in the IG introduced more soft/small food pieces (P = 0.004) but not more complex textures (P = 0.15). There was no group difference in children acceptance for any of the textured foods offered in the laboratory. Independent of their study group, children's exposure to texture was associated with birth order, self-feeding with fingers, low gagging frequency and seldom use of commercial baby foods. Higher acceptance was associated with higher exposure to food pieces but not to pureed foods (either smooth or rough) and with children's eating behavioural traits (high food enjoyment, high food responsiveness and low food fussiness). This pilot intervention demonstrated that providing information can be effective in promoting the introduction of small and soft food pieces, but the most effective way to influence the introduction of more challenging textures (hard pieces and double texture) is uncertain. Further research should focus on the identification of barriers to complex texture introduction and on how building on this knowledge for a population-based public health intervention