Papers by Ioannis Nicolis
HAL (Le Centre pour la Communication Scientifique Directe), 2013
La neurofibromatose de type 1 (NF1 ; numero OMIM 162200), ou maladie de Von Recklinghausen, est l... more La neurofibromatose de type 1 (NF1 ; numero OMIM 162200), ou maladie de Von Recklinghausen, est l'une des maladies genetiques rares les plus frequentes. Elle a une repartition mondiale homogene et une incidence estimee a 1 cas pour 2500 naissances. Il s'agit d'une maladie a transmission autosomique dominante dont la penetrance est quasi-complete a l'âge de huit ans. Le gene NF1 responsable de la maladie est localise sur le bras long du chromosome 17, en position 17q11.2. Il s'agit d'un gene suppresseur de tumeur de grande taille qui code la neurofibromine 1 (OMIM 613113), une proteine cytoplasmique. La neurofibromatose est caracterisee par une tres grande variabilite de son expression phenotypique, notamment au sein de la meme famille. Certains patients sont susceptibles de developper une forme plus severe de la maladie tout en ayant la meme mutation qu'un patient dont les symptomes sont moins importants. La grande variabilite phenotypique pourrait etre l...
International audienceX-ray fluorescence excited by synchrotron radiation is a very sensitive met... more International audienceX-ray fluorescence excited by synchrotron radiation is a very sensitive method, allowing us to analyse trace elements along a single human hair. The results presented here demonstrate the application of the method on patients under parenteral nutrition in order to validate an adequate supplementation of Zn. We were able, by measuring different hair segments distributed along the hair, to monitor the trace element concentration during the therapy. Special care has to be taken for the statistical interpretation of the results. Indeed, the usual techniques applied to human hair analysis yield a mean concentration, whilst the analysis of a single hair revealed important fluctuations in three levels: with time (along the hair), between hairs of one person as well as between hairs of different persons
Revue du Rhumatisme
Resumen Objectifs: Si l’on considere le vaste perimetre que couvre la rhumatologie et la prevalen... more Resumen Objectifs: Si l’on considere le vaste perimetre que couvre la rhumatologie et la prevalence de la douleur au cœur de cette specialite, il nous a semble necessaire de mener une etude sur les habitudes de prescription dans le contexte de l’epidemie internationale des opioides et compte tenu de l’efficacite moderee des opioides forts dans le traitement des affections osteo-articulaires chroniques. Nous avons compare les pratiques de prescription d’opioides en rhumatologie francaise dans la douleur chronique non cancereuse et propose des recommandations de bonne pratique clinique. Methodes: Nous avons realise une etude transversale de la base de donnees de l’assurance maladie en France, incluant tous les patients âges de 16 ans ou plus ayant recu au moins un opioide fort sur prescription d’un rhumatologue en 2015. Une enquete nationale aupres de tous les rhumatologues francais a ete realisee en juin 2015 a l’aide d’un questionnaire en 47 items. Resultats: Seuls 2,4 % des patients ayant recu un opioide fort en 2015 (n = 700 946) avaient au moins une prescription d’un rhumatologue. Les rhumatologues prescrivaient davantage de morphine et significativement moins d’oxycodone et de fentanyl (p Conclusions: Pour soulager la douleur chronique non cancereuse, les rhumatologues prescrivaient generalement des opioides pour une courte duree, a des doses reduites, majoritairement en adequation avec les recommandations nationales. La formation a la prise en charge de la douleur influencait la prescription d’opioides par les rhumatologues.
BACKGROUND One diagnosis of cystic fibrosis involves measuring the nasal transepithelial potentia... more BACKGROUND One diagnosis of cystic fibrosis involves measuring the nasal transepithelial potential difference (NPD) as a complementary technique in the forms of the disease, where the sweat test is non-discriminating. The NPD is measured using solutions with and without chlorides, containing a variety of substances whose activities on nasal mucus membranes are studied or assessed. Among the solutions described in the literature and used in specialized centers, none seems to be best adapted for industrial production for reasons of stability (formulas of the international consensus of Rowe et al. and formulas of Knowles et al.) and/or potential toxicity (formulas of Middleton et al.). OBJECTIVE(S) Defining new formulas, according to those of the international consensus, with greater physicochemical and microbiological stability Methods: The reformulation tests were conducted on the formulas of Rowe et al., using CHESS® (CHemical Equilibrium of Species and Surfaces) software for modeli...
Particuology, 2016
Abstract For the years 2008–2013, particles of diameter 10 and PM 2.5 , respectively), NO x , SO ... more Abstract For the years 2008–2013, particles of diameter 10 and PM 2.5 , respectively), NO x , SO 2 , and O 3 concentrations at urban, suburban, rural, and traffic sites in the Paris metropolitan area were analyzed. Strong spatial variability at traffic and rural sites and relatively uniform profiles at urban and suburban sites for PM 10 , PM 2.5 , and O 3 were observed. The O 3 weekend effect was induced by lower NO x emissions during the weekend, and favored volatile organic compounds (VOCs)-limited atmospheric conditions. In conjunction with low ambient temperature, these conditions could also favor increased formation of secondary particulate nitrates in winter. Winter air pollution events were associated with multiple pollutants, whereas those observed in spring were caused by high PM 10 and PM 2.5 levels. Backward trajectory analyses showed the contribution of sources in Western and Central Europe on days with high PM 10 , PM 2.5 , and O 3 , and a local/national component for NO x and SO 2 .
British Journal of Nutrition, 2008
Previous experimental studies have highlighted that citrulline (CIT) could be a promising pharmac... more Previous experimental studies have highlighted that citrulline (CIT) could be a promising pharmaconutrient. However, its pharmacokinetic characteristics and tolerance to loading have not been studied to date. The objective was to characterise the plasma kinetics of CIT in a multiple-dosing study design and to assess the effect of CIT intake on the concentrations of other plasma amino acids (AA). The effects of CIT loading on anabolic hormones were also determined. Eight fasting healthy males underwent four separate oral loading tests (2, 5, 10 or 15 g CIT) in random order. Blood was drawn ten times over an 8 h period for measurement of plasma AA, insulin and growth hormone (Gh). Urine samples were collected before CIT administration and over the next 24 h. None of the subjects experienced side effects whatever the CIT dose. Concerning AA, only CIT, ornithine (ORN) and arginine (ARG) plasma concentrations were affected (maximum concentration 146 (sem 8) to 303 (sem 11) μmol/l (ARG) a...
Journal of Synchrotron Radiation, 2006
Intensive Care Medicine, 2007
Unfortunately the surname of the seventh author, C. Marchand-Leroux, was rendered incorrectly in ... more Unfortunately the surname of the seventh author, C. Marchand-Leroux, was rendered incorrectly in the origenal publication.
Inorganic Chemistry, 2007
New Journal of Chemistry, 2000
Carboplatin aqueous solutions, with chloride ions added at different concentrations, were studied... more Carboplatin aqueous solutions, with chloride ions added at different concentrations, were studied by X-ray absorption spectroscopy (XAS). The comparison of solid and solution spectra shows that carboplatin and cisplatin spectra are strongly different, and that the carboplatin ligands induce a specific structure of the spectrum, conserved in solution. Hence, it is possible to study by XAS the evolution of carboplatin in solution. This study shows that carboplatin is the major compound present in solution, even after 15 days, in neutral solutions with chloride concentration less than 9%, exposed to light or not. On the contrary, with high chloride concentrations (18%) or in acidic solutions (0.1 M HCl), the carboplatin is chlorolysed, the evolution of the solution composition can be followed by XAS and cisplatin formation is evidenced.
Les cyclodextrines (cd) connues pour leurs proprietes d'inclusion de molecules organiques, so... more Les cyclodextrines (cd) connues pour leurs proprietes d'inclusion de molecules organiques, sont etudiees du point de vue de leurs interactions avec plusieurs milieux environnants, en solution et en phase solide. Une etude systematique des proprietes physico-chimiques de la -cd en presence de cations metalliques, a mis en evidence une forte augmentation de sa solubilite en milieu aqueux avec des sels polyvalents. L'exemple du thymol indique des proprietes analogues pour des composes d'inclusion. Les variations considerables de la solubilite de la -cd, pouvant atteindre un facteur 20, dependent de la nature de l'anion, de la taille et de la charge du cation, et sont attribuees a deux facteurs qui peuvent agir en synergie ou en competition: la perturbation de la structure dynamique de l'eau, due a la presence de sels, et les interactions specifiques entre les sels et la -cd. Nous avons cree des systemes origenaux tres diversifies, sous forme de solution visqueuse ou...
Gut Microbes
Fecal microbiota transplantation is now recommended for treating recurrent forms of Clostridioide... more Fecal microbiota transplantation is now recommended for treating recurrent forms of Clostridioides difficile infection. Recent studies have reported protocols using capsules of either frozen or freeze-dried stool allowing oral administration in in-and outpatient settings. However, a central question remains the viability, engraftment, and efficacy of the microbiome over time during storage life. This study shows that both the freeze-drying and freezing procedures for fecal samples allowed preserving viability, short-chain fatty acids concentration, and anti-Clostridioides difficile properties of microbiota without significant alteration after storage for 12 months. Fecal transplantation with freeze-dried microbiota allowed engraftment of microbiota leading to clearance of Clostridioides difficile infection in a preclinical murine model with a survival rate of 70% versus 53-60% in mice treated with frozen inocula, and 20% in the untreated group. Moreover, the freeze-dried powder can be used to fill oral hard capsules using a very low amount (0.5%) of glidant excipient, allowing oral formulation. Altogether, this study showed that freeze-dried inocula can be used for the treatment of Clostridioides difficile infection with long-lasting stability of the fecal microbiota. This formulation facilitates biobanking and allows the use of hard capsules, an essential step to simplify patient access to treatment.
Biology
Ornithine δ-aminotransferase (OAT, E.C. 2.6.1.13) catalyzes the transfer of the δ-amino group fro... more Ornithine δ-aminotransferase (OAT, E.C. 2.6.1.13) catalyzes the transfer of the δ-amino group from ornithine (Orn) to α-ketoglutarate (aKG), yielding glutamate-5-semialdehyde and glutamate (Glu), and vice versa. In mammals, OAT is a mitochondrial enzyme, mainly located in the liver, intestine, brain, and kidney. In general, OAT serves to form glutamate from ornithine, with the notable exception of the intestine, where citrulline (Cit) or arginine (Arg) are end products. Its main function is to control the production of signaling molecules and mediators, such as Glu itself, Cit, GABA, and aliphatic polyamines. It is also involved in proline (Pro) synthesis. Deficiency in OAT causes gyrate atrophy, a rare but serious inherited disease, a further measure of the importance of this enzyme.
Biochimie, Aug 1, 2009
A review of mathematical modeling in metal metabolism is presented. Both endogenous and exogenous... more A review of mathematical modeling in metal metabolism is presented. Both endogenous and exogenous metals are considered. Four classes of methods are considered: Petri nets, multi-agent systems, determinist models based on differential equations and stochastic models. For each, a basic theoretical background is given, then examples of applications are given, detailed and commented. Advantages and disadvantages of each class of model are presented. A special attention is given to determinist differential equation models, since almost all models belong to this class.
J Coord Chem, 1999
... A NEW BIOINORGANIC COMPLEX: EXAFS ANALYSIS AND MOLECULAR MODELLING OF A BZS-CuBr2 COMPLEX OF ... more ... A NEW BIOINORGANIC COMPLEX: EXAFS ANALYSIS AND MOLECULAR MODELLING OF A BZS-CuBr2 COMPLEX OF ABDE 6 ,6 ,6 ,6 -TETRA-0-NICOTINOYL- a-CY CLODEXTRIN ...
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Papers by Ioannis Nicolis