Spéciation chimique et immunotoxicologie du béryllium : effets thérapeutiques des agents complexants NTA, NTP et tiron

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Improvement of the chemical resistance of zirconium fluoride glasses coated with a Tiron (R) modified tin oxide layer prepared by the sol-gel process

In order to improve the chemical resistance of zirconium fluoride glass a protective transparent SnO2 layer was deposited by the solgel dip-coating process in the presence of Tiron (R) as particle surface modifier agent. After water immersion for different periods of time, both coated and non-coated fluoride glasses were analyzed by scanning electron microscopy, mass loss evaluation, infrared spectroscopy and X-ray photoelectron spectroscopy. In contrast to the effects occurring for non-coated glass, where the surface undergoes a rapid selective dissolution of the most soluble species, the results for the SnO2-coated glass showed that the filling of the film nanopores by dissolved glass material results in a hermetic barrier protecting the glass surface. The selective glass dissolution was confirmed by liquid chromatography measurements of the etching solution after each exposure time. (c) 2006 Elsevier B.V. All rights reserved.

Ethanol-induced vasoconstriction is mediated via redox-sensitive cyclo-oxygenase-dependent mechanisms

The present study investigated the role of ROS (reactive oxygen species) and COX (cyclooxygenase) in ethanol-induced contraction and elevation of [Ca(2+)](i) (intracellular [Ca(2+)]). Vascular reactivity experiments, using standard muscle bath procedures, showed that ethanol (1-800 mmol/l) induced contraction in endothelium-intact (EC(50): 306 +/- 34 mmol/l) and endothelium-denuded (EC(50): 180 +/- 40 mmol/l) rat aortic rings. Endothelial removal enhanced ethanol-induced contraction. Preincubation of intact rings with L-NAME [N(G)-nitro-L-arginine methyl ester; non-selective NOS (NO synthase) inhibitor, 100 mu mol/l], 7-nitroindazole [selective nNOS (neuronal NOS) inhibitor, 100 mu mol/l], oxyhaemoglobin (NO scavenger, 10 mu mol/l) and ODQ (selective inhibitor of guanylate cyclase enzyme, 1 mu mol/l) increased ethanol-induced contraction. Tiron [O(2)(-) (superoxide anion) scavenger, 1 mmol/l] and catalase (H(2)O(2) scavenger, 300 units/ml) reduced ethanol-induced contraction to a similar extent in both endothelium-intact and denuded rings. Similarly, indomethacin (non-selective COX inhibitor, 10 mu mol/l), SC560 (selective COX- I inhibitor, 1 mu mol/l), AH6809 [PGF(2 alpha) (prostaglandin F(2 alpha))] receptor antagonist, 10 mu mol/l] or SQ29584 [PGH(2)(prostaglandin H(2))/TXA(2) (thromboxane A(2)) receptor antagonist, 3 mu mol/l] inhibited ethanol-induced contraction in aortic rings with and without intact endothelium. In cultured aortic VSMCs (vascular smooth muscle cells), ethanol stimulated generation of O(2)(-) and H(2)O(2). Ethanol induced a transient increase in [Ca(2+)](i), which was significantly inhibited in VSMCs pre-exposed to tiron or indomethacin. Our data suggest that ethanol induces vasoconstriction via redox-sensitive and COX-dependent pathways, probably through direct effects on ROS production and Ca(2+) signalling. These findings identify putative molecular mechanisms whereby ethanol, at high concentrations, influences vascular reactivity. Whether similar phenomena occur in vivo at lower concentrations of ethanol remains unclear.

Impaired calcium influx despite hyper-reactivity in contralateral carotid following balloon injury: eNOS involvement

Balloon catheter injury results in hyper-reactivity to phenylephrine in contralateral carotids. Decreased nitric oxide (NO) modulation and/or increased intracellular calcium concentration triggers vascular smooth muscle contraction. Therefore, this study explores the participation of NO signaling pathway and calcium mobilization on hyper-reactivity to phenylephrine in contralateral carotids. Concentration-response curves for calcium (CaCl(2)) and phenylephrine were obtained in control and contralateral carotids four days after balloon injury, in the presence and absence of the inhibitors (L-NAME, L-NNA, 1400W, 7-NI, Oxyhemoglobin, ODQ or Tiron). Confocal microscopy using Fluo-3AM or DHE was performed to detect the intracellular levels of calcium and reactive oxygen species, respectively. The modulation of NO on phenylephrine-induced contraction was absent in the contralateral carotid. Phenylephrine-induced intracellular calcium mobilization was not altered in contralateral carotids. However, extracellular calcium mobilization by phenylephrine was reduced in the contralateral carotid compared to control arteries, and this result was confirmed by confocal microscopy. L-NAME increased phenylephrine-induced extracellular calcium mobilization in the contralateral carotid to the control levels. Results obtained with L-NNA, 1400W, 7-NI, OxyHb, ODQ or Tiron showed that this response was mediated by products from endothelial NOS (eNOS) different from NO and without soluble guanylate cyclase activation, but it involved superoxide anions. Furthermore. Tiron or L-NNA reduced the levels of reactive oxygen species in contralateral carotids. Data suggest that balloon catheter injury promoted eNOS uncoupling in contralateral carotids, which generates superoxide rather than NO, and reduces phenylephrine-induced extracellular calcium mobilization, despite the hyper-reactivity to phenylephrine in contralateral carotids. (C) 2010 Elsevier B.V. All rights reserved.

An Apparent Paradox: Attenuation of Phenylephrine-mediated Calcium Mobilization and Hyperreactivity to Phenylephrine in Contralateral Carotid After Balloon Injury

Balloon catheter injury promotes hyperreactivity to phenylephrine (Phe) in the contralateral carotid. Phe-induced contraction involves calcium mobilization, a process that may be sensitive to reactive oxygen species. In this study, we investigated whether increased reactivity to Phe in the contralateral carotid is due to alterations in calcium mobilization by Phe and reactive oxygen species signaling. Concentration-response curves to Phe were obtained in control and contralateral arteries 4 days after balloon injury. Tiron did not modify E(max) to Phe in control arteries but reduced this parameter in the contralateral carotid to control levels. Moreover, immunofluorescence to dihydroethydine showed increased basal oxidative stress in the contralateral artery compared with control artery. Intracellular calcium mobilization by Phe in the contralateral artery was not different from control, but Phe-induced extracellular calcium mobilization was reduced in the contralateral artery compared with that in the control. These data were confirmed by confocal microscopy using Fluo 3-AM. Tiron and SC-236 increased Phe-induced calcium influx in the contralateral artery, which was similar to controls in the same conditions. However, catalase did not modify this response. Taken together, our results suggest that superoxide anions and prostanoids from cyclooxygenase-2 alter pathways downstream of alpha(1)-adrenoceptor activation in the contralateral carotid in response to injury. This results in reduced Phe-induced calcium influx, despite hyperreactivity to Phe.

Mélanges de poésie.

Poème de Tobie (1). — Mag. Alexandri Laus sapientiae divinae {40). — Pièces de vers composées par Jo. Prevost (89), Fr, Caulier (90), Lud. Hurillon (91, 93), J. Mentel (94), N. Leon. Bursarius (95), J. Fr. Mondolot. (96), Fr. Boutard (99), Am. du Mas (106), Car. Thiery (112), Ben. Thibaud (113), Fr. de Clermont Thoury (139), Pet, Neveletus. Doschius (169), Car. Fr. Thiery (184), Seb. Tripier (276), Franc. Linant (323), Jos. Rosset (351), Rob. Wallery (363), Ren. Pr. Tassin (371), Jo. Henr. Wentsel (373). — Extr. du ms. 553 du Vatican (104). — Lettre des religieux de Tiron à Jean Casimir, roi de Pologne (178). — Épitaphes et inscriptions modernes, plusieurs composées par Mabillon. — Deux vieilles épitaphes de l'église de: Lagny (262). Inscription antique de Vicence (311). — Distiques de l'abbé Serlon (355). Épitaphe. de Ratherius (356). — Qq. pièces en français et en italien.

Extracellular superoxide dismutase is a major determinant of nitric oxide bioavailability: in vivo and ex vivo evidence from ecSOD-deficient mice.

The bioavailability of nitric oxide (NO) within the vascular wall is limited by superoxide anions (O2.-). The relevance of extracellular superoxide dismutase (ecSOD) for the detoxification of vascular O2.- is unknown. We determined the involvement of ecSOD in the control of blood pressure and endothelium-dependent responses in angiotensin II-induced hypertension and renovascular hypertension induced by the two-kidney, one-clip model in wild-type mice and mice lacking the ecSOD gene. Blood pressure was identical in sham-operated ecSOD+/+ and ecSOD-/- mice. After 6 days of angiotensin II-treatment and 2 and 4 weeks after renal artery clipping, blood pressure was significantly higher in ecSOD-/- than ecSOD+/+ mice. Recombinant ecSOD selectively decreased blood pressure in hypertensive ecSOD-/- mice, whereas ecSOD had no effect in normotensive and hypertensive ecSOD+/+ mice. Compared with sham-operated ecSOD+/+ mice, sham-operated ecSOD-/- mice exhibited attenuated acetylcholine-induced relaxations. These responses were further depressed in vessels from clipped animals. Vascular O2.-, as measured by lucigenin chemiluminescence, was higher in ecSOD-/- compared with ecSOD+/+ mice and was increased by clipping. The antioxidant tiron normalized relaxations in vessels from sham-operated and clipped ecSOD-/-, as well as from clipped ecSOD+/+ mice. In contrast, in vivo application of ecSOD selectively enhanced endothelium-dependent relaxation in vessels from ecSOD-/- mice. These data reveal that endogenous ecSOD is a major antagonistic principle to vascular O2.-, controlling blood pressure and vascular function in angiotensin II-dependent models of hypertension. ecSOD is expressed in such an abundance that even in situations of high oxidative stress no relative lack of enzyme activity occurs.

Alternativas analíticas para determinação de ferro e titânio em cimento Portland

In the present work four different analytical methodologies were studied for the determination of iron and titanium in Portland cement. The cement samples were dissolved with hot HCl and HF, being compared Fe and Ti concentrations through four analytical methods: molecular absorption spectrophotometry using the reagents 1,2-hydroxybenzene-3,5-disulfonic acid (Tiron) and the 5-chloro-salicylic acid (CSA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and flame atomic absorption spectrophotometry (FAAS). In the spectrophotometric determinations were studied pH conditions, reagents addition order, interferences, amount of reagents, linear range and stability of the system. In the techniques of ICP-AES and FAAS were studied the best lines, interferences, sensibility and linear range. The obtained results were compared and the agreement was evaluated among the methods for the determination of the metals of interest.

Recueil d'extraits de divers chartriers de Bretagne.

Extraits des archives de l'église cathédrale (p. 1), de Saint-Melaine (p. 53, 461) et de Saint-Georges (p. 129) de Rennes, — de Saint-Sulpice (p. 177), — de Saint-Pierre de Rillé (p. 231), — de la sénéchaussée de Rennes (p. 295), — de M. de Rosnyvinen, XVe siècle (p. 321), — du château et du prieuré de Vitré (p. 337), — de la seigneurie et de l'abbaye de Montfort (p. 401), — des Cordeliers de Dinan (p. 491), — de la maison de La Marzelière (p. 499), — des abbayes de La Vieuville (p. 511), — Notre-Dame du Tronchet (p. 621), Tiron (p. 633), Saint-Jagu (p. 643), Mont-Saint-Michel (p. 663) et Savigny (p. 731), — du château de Blain (p. 763), — du Carmel de Nantes (p. 943), — de la chartreuse de Buzay (p. 967).

Mélanges. — Extraits de cartulaires.

Contient : Extrait du testament d'Étienne, comte de Montbéliard ; Charte de Louis, comte de Ferrette, pour l'abbaye de Pairis ; Couronnement de Charles le Chauve à Metz (869), etc ; Donation faite par Louis de Luxembourg, comte de Saint-Pol, à Antoine Villiers de l'Isle-Adam ; Mandement de Louis XI à Jacques Villiers de l'Isle-Adam de prendre possession de la ville de Paris ; Extraits du cartulaire de Brioude ; Charte du vicomte Néel pour l'abbaye de Jumièges ; Historia Selebiensis, Eboracensis dioceseos (cf. Labbe, Bibl. Nova, I, p. 594) ; Extraits d'un obituaire de l'église du Mans ; Donation de Louis, duc de Bourbon, à la même église ; Extraits du cartulaire de Saint-Aubin d'Angers ; Généalogie des fondateurs de l'abbaye de Jouarre, d'après un martyrologe ; Notice sur les origines de Ferrières en Gâtinais ; Liste des bulles pontificales de Fontevrault ; Chartes de Vernon ; Charte de Robert, duc de Normandie, pour le monastère de Montivilliers ; Extraits de l'obituaire d'Hérivaux ; Tableau des filiales de Clairvaux ; Extraits du cartulaire d'Auberive, au diocèse de Langres ; Extraits du cartulaire de Longuay ; Extraits du cartulaire de Montiérender ; Extraits du cartulaire de l'Isle-en-Barrois ; Extraits du cartulaire de Beaulieu en Limousin ; Extraits d'un cartulaire de l'évêché de Langres ; Extraits d'un cartulaire de l'église d'Angers ; Extraits d'un cartulaire de Royaumont ; Extraits d'un registre de Saint-Merri de Paris ; Chartes d'Angers ; Extraits de l'inventaire des titres de Notre-Dame-des-Clairets ; Accord entre Robert, comte de Dreux, et l'évêque de Paris (1209 ; — il y en a une autre copie au fol. 150) ; Extraits du cartulaire de la forêt de Halatte ; Chartes de Vierzon ; Extraits du cartulaire de Massay ; Généalogie des seigneurs de Vierzon ; Diplôme de Louis d'Outre-Mer pour Saint-Merri ; Extraits des cartulaires de l'évêché de Paris ; Chartes de Grammont ; Extraits du cartulaire de Maubuisson ; Extraits de l'obituaire de Sainte-Croix d'Orléans ; Extraits du cartulaire de la chapelle de Saint-Lazare de Blois ; Extraits du cartulaire de Notre-Dame du Bourg-Moyen de Blois. [Ms. Vatic. Ottoboni 2960] ; Extrait des titres de l'abbaye de l'Étoile (de Poitiers) ; Chartes de La Merci-Dieu ; Extraits du cartulaire de Saint-Martin-des-Champs concernant les seigneurs du Puiset ; Extraits d'un cartulaire de Saint-Père de Chartres ; Extraits d'un martyrologe de l'église de Chartres ; Extraits des cartulaires de Saint-Père ; Lettre de Manassès, archevêque de Reims, à Hugues de Die ; Extrait d'un obituaire de Saint-Barthélemi de Béthune ; Charte de Baudouin V, comte de Flandre, pour l'abbaye de Marchiennes ; Échange entre l'abbaye de Saint-Vaast d'Arras et Robert, comte de Flandre ; Charte de Philippe I pour l'église Saint-Pierre d'Aire ; Charte de Hugues, châtelain de Cambrai, pour l'abbaye du Mont-Saint-Éloi ; Charte d'Enguerrand, comte de Saint-Pol, pour l'abbaye de Marchiennes ; Charte de Thierri, comte de Flandre, pour Enguerrand, comte de Saint-Pol ; Chartes d'Eaucourt en Artois ; Charte de Jean, êvêque de Thérouanne, pour l'église Saint-Pierre de Lille ; Note sur le mariage d'Isabeau de Barbazan ; Inventaire de reliques, extrait d'un processionnaire de l'église de Soissons ; Extrait d'un cartulaire du prieuré de Donchery ; Catalogue des abbés de Montiéramey ; Catalogue des abbesses de Notre-Dame-du-Lys ; Charte de Brunon, abbé de Montiéramey ; Extraits du cartulaire d'Uzerche ; Extraits de chartes de la Couture du Mans ; Extraits du cartulaire de Bonlieu en Limousin ; Notes sur la maison de Mercoeur ; Extraits d'un martyrologe de Saint-Séverin de Paris ; Extraits du cartulaire de Vendôme ; Extraits du cartulaire de Saint-Pierre de Beauvais ; Extraits du cartulaire de Saint-Rémi de Reims ; Catalogue des abbés de la Chaise-Dieu ; Extraits du cartulaire de Saint-Nicaise de Meulan ; Extraits de la chronique de Saint-Mihiel de Verdun ; Serment prêté par l'hérésiarque Bérenger ; Extraits d'obituaires du Mont-Saint-Michel ; Extraits des titres de Saint-Ulface ; Extraits du cartulaire de Saint-Vincent du Mans ; Extraits du cartulaire de Nogent-le-Rotrou ; Extrait du cartulaire de Pont-aux-Dames (de Meaux) ; Chartes du prieuré de Lavardin ; Extraits d'un cartulaire de Saint-Vincent de Laon ; Extraits du cartulaire rouge de l'église de Laon ; Chartes de Saint-Quentin près Beauvais ; Extraits du cartulaire de Vierzon ; Extraits du cartulaire de Beaulieu ; Notes sur les chartes de Subiaco ; Extraits du cartulaire de Saint-Thierry de Reims ; Extraits d'un martyrologe de Saint-Avold ; Chartes de Saint-Martin d'Épernay ; Chartes de Saint-Vincent-au-Bois ; Extraits du cartulaire de Tiron ; Extraits des archives de Saint-Bavon de Gand ; Extraits du cartulaire de Marchiennes ; Extraits des archives de Saint-Pierre de Gand ; Charte de Robert, comte de Flandre, pour l'église de Tronchiennes ; Charte de Baudouin, comte de Flandre, pour l'abbaye d'Einham ; Extraits des archives de l'évêché de Gand ; Extraits de cartulaires de Saint-Bavon ; Extraits des cartulaires et registres de Fontevrault ; Extraits des titres de Beaugerais ; Chartes de Villeloin ; Extraits d'un cartulaire de l'église d'Amiens ; Extraits du cartulaire de Clairmarais ; Titres de Saint-Bertin ; Charte de Baudouin, comte de Flandre, pour l'abbaye de Marchiennes

Study of structural surface modified tin oxide membrane prepared by sol-gel route sintered at 400 degrees C

This work describes the chemical modification by Tiron(R) molecules of the surface of SnO2 nanoparticles used to prepare nanoporous membranes. Samples prepared with Tiron(R) content between 1 and 20 wt% and fired at 400 C were characterised by X-Ray Powder Diffraction (XRPD), Extended X-ray Absorption Fine Structure (EXAFS), N-2 adsorption isotherms analysis and permeation experiments. XRPD and EXAFS results show a continuous reduction of crystallite size by increasing the Tiron(R) contents until 7.5 wt%. The control exercised by Tiron(R) modifying agent in crystallite growth allows the fine tuning of the average pore size that can be screened from 0.4 to 4 nm as the amount of grafted molecules decreases from 10 to 0 wt%. In consequence, the membrane cut-off can be screened from 1500 to 3500 g.mol(-1).

Small angle X-ray scattering study of surface modified tin oxide nanoparticles prepared by sol-gel route

The surface properties of SnO2 nanoparticles were modified by grafting ionic (Tiron (R). (OH)(2)C6H2(SO3Na)(2)(H2O)-H-.) or non-ionic (Catechol (R). C6H4-1,2-(OH)(2)) capping Molecules during aqueous sol-gel processing to improve the redispersibility of powdered xerogel. The effect of the amount of grafted organic molecules on the redispersibility of powders in aqueous solution at several basic pH values was Studied. The nanostructural features of the colloidal suspensions were analyzed by small angle X-ray scattering (SAXS) measurements. Irrespective of the nature and amount of grafted molecules, complete redispersion was obtained in aqueous solution at pH = 13. The redispersion at pH = 11 results in a mixture of dispersed primary particles and aggregates. The proportion of well dispersed nanoparticles and aggregates (and their average size) can be tuned by the quantity of grafted ionic molecules.

Preparation of ceramic membranes from surface modified tin oxide nanoparticles

The preparation of crack-free SnO2 supported membranes requires the development of new strategies of synthesis capable to allow controlled changes of surface chemistry and to improve the processability of supported layers. In this way, the controlled modification of the SnO2 nanoparticle surface by adding capping molecules like Tiron(R) ((OH)(2)C6H2(SO3Na)(2)) during the sol-gel process was studied, aiming to obtain high performance membranes. Colloidal suspensions were prepared by hydrolyzing SnCl4.5H(2)O aqueous solution with NH4OH in presence of Tiron(R). The effect of the amount of Tiro(R) (from I to 20 wt.%) on the structural features of nanoparticles, powder redispersability and particle-solution interface properties was investigated by X-ray powder diffraction (XRPD), extended X-ray absorption fine structure (EXAFS), quasi-elastic light scattering and electrophoretic mobility measurements. XRPD and EXAFS results showed that the addition of Tiron(R) up to 20 wt.% to colloidal suspensions does not affect the crystallite size of SnO2 primary particles, determined around 2-3 nm. This value is comparable to the hydrodynamic size measured after redispersion of powder prepared with amount of Tiro(R) higher than 7.5 wt.%, indicating the absence of condensation reactions between primary particles after the initial precipitation step. As a consequence the powder with amount of Tiron(R) > 7.5 wt.%, can be fully redispersed in aqueous solution at pH greater than or equal to I I until a nanoparticle concentration of 6 vol.%. The electrophoresis measurements showed a decrease of the isoelectric point by increasing the amount of grafted Tiron(R) at the SnO2 nanoparticle surface, resulting in negatively charged particle-solution interface in all the studied pH range (2-11). These features govern the gelation process favoring the preparation of crack-free SnO2 supported membranes. The control exercised by Tiron(R) modifying agent in the aggregation process allows the fine-tuning of the porosity, from 0.124 to 0.065 cm(3) g(-1), and mean pore size, from 6.4 to 1.9 nm, as the amount of grafted molecules increases from 0 to 10 wt.%. In consequence, the membrane cut-off determined by filtration of polyethylene glycol standard solutions can be screened from 1500 to 3500 g mol(-1). (C) 2002 Elsevier B.V. B.V. All rights reserved.

XPS study on water corrosion of fluorzirconate glasses and their protection by a layer of surface modified tin dioxide nanoparticles

The surface corrosion process associated with the hydrolysis of fluorozirconate glass, Z-BLAN (53ZrF(4), 20BaF(2), 20NaF, 4LaF(2), 3AlF(3)), and the corrosion protection efficiency of a nanocrystalline transparent SnO2 layer were investigated by X-ray photoelectron spectroscopy. The tin oxide film was deposited by the sol-gel dip-coating process in the presence of Tiron(R) as particle surface modifier agent. The chemical bonding structure and composition of the surface region of coated and non-coated ZBLAN were studied before water contact and after different immersion periods (5-30 min). In contrast to the effects occurring for non-coated glass, where the surface undergoes a rapid selective dissolution of the most soluble species inducing the formation of a new surface phase consisting of stable zirconium oxyfluoride, barium fluoride and lanthanum fluoride species, the results for the SnO2-coated glass showed that the hydrolytic attack induces a filling of the film nanopores by dissolved glass material and the formation of tin oxylluoride and zirconium oxyfluoride species. This process results in a modified film, which acts as a hermetic diffusion barrier protecting efficiently the glass surface. (C) 2006 Elsevier B.V. All rights reserved.