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Sodium Fluoride (sodium + fluoride)
Selected AbstractsSolubilizing Sodium Fluoride in Acetonitrile: Synthesis, Molecular Structure, and Complexation Behavior of Bis(organostannyl)methyl-Substituted Crown Ethers,CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2007Gregor Reeske Dr. Abstract The synthesis of the crown-ether-substituted bis(organostannyl)methanes Ph3SnCH2Sn(Ph2)-CH2 -[16]crown-5 (1) and Ph2ISnCH2Sn(I)(Ph)-CH2 -[16]crown-5 (2) is reported. Both compounds have been characterized by elemental analyses, 1H, 13C, 19F, and 119Sn,NMR spectroscopy, and in the case of compound 2 also by electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analysis revealed for the aqua complex 2,H2O trigonal,bipyramidal-configured tin atoms with intramolecular Sn(1)O(1) and Sn(2)O(1W) distances of 2.555(2) and 2.440(3),Å, respectively. The water molecule is trapped in a sandwich-like fashion between the crown ether oxygen atoms O(2) and O(4) and the Sn(2) atom. NMR spectroscopy unambiguously proved the ability of compound 2 in acetonitrile to overcome the high lattice energy of sodium fluoride and to complex the latter under charge separation. [source] Physico-chemical characterisation of 99mTc-tin fluoride colloid agent used for labelling white cellsJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 6 2006Chris Tsopelas Abstract 99mTc,tin fluoride colloid is an agent used to label leucocytes, for the imaging and diagnosis of inflammatory conditions including Crohn's disease. Despite previous investigations, this radiolabelling agent is still poorly characterised. The aim of this work was to examine the process of formation and stability of 99mTc,tin fluoride colloid using mass spectrometry, membrane filtration and atomic absorption spectrophotometric techniques. Tin-oxide bonds in tin clusters were identified in the stannous fluoride reagent vial by mass spectrometry. From radioactive particle size distribution experiments, the facile disruption of radiocolloid particles with excess oxygen gas contrasted to the partial hydrolysis of Sn(II) during the formation process. Under the standard conditions, 10% of particles were determined as 1,3 µm, and this population coordinated 96% of the 99mTc added. Colloid particle formation and the reduction of 99mTc-pertechnetate is discussed. Sodium fluoride may optimise 1,3 µm radioactive particle size, by regulating particle growth. 99mTc,tin fluoride colloid is affected by positive or negative charge, as either Al, Mo ions or solid membranes, resulting in either coagulation and/or deflocculation of the particles. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effect of root surface treatment with propolis and fluoride in delayed tooth replantation in ratsDENTAL TRAUMATOLOGY, Issue 6 2008Jéssica Lemos Gulinelli Nevertheless, an extended extraoral period damages the periodontal ligament and results in external root resorption. The purpose of this study was to assess by histologic and histometric analysis, the influence of propolis 15% (natural resinous substance collected by Apis mellifera bees from various plants) and the fluoride solution used as root surface treatment on the healing process after delayed tooth replantation. Thirty Wistar (Rattus norvegicus albinus) rats were submitted to extraction of their upper right incisor. The teeth were maintained in a dry environment for 60 min. After this, the pulp was extirpated and the papilla, enamel organ and periodontal ligament were removed with scalpel. The teeth were divided into three experimental groups: Group I , teeth immersed in 20 ml of physiologic saline; Group II , teeth immersed in 20 ml of 2% acidulated phosphate sodium fluoride; Group III , teeth immersed in 20 ml of 15% propolis. After 10 min of immersion in the solutions, the root canals were dried and filled with calcium hydroxide paste and the teeth were replanted. The animals were euthanized 60 days after replantation. The results showed that similar external root resorption was seen in the propolis and fluoride groups. Teeth treated with physiologic saline tended to have more inflammatory root resorption compared with those treated with fluoride or propolis. However, the comparative analysis did not reveal statistically significant differences (P > 0.05) between the treatment modalities when used for delayed tooth replantation. [source] 1H and 19F nuclear magnetic resonance microimaging of water and chemical distribution in soil columnsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2007Myrna J. Simpson Abstract Nuclear magnetic resonance (NMR) microimaging is a noninvasive and nondestructive technique that has great potential for the study of soil processes. Hydrogen-1 NMR microimaging techniques were used to examine the distribution of water in four different soil cores. Fluorine-19 NMR microimaging is also used to study the transport of three model contaminants (hexafluorobenzene, sodium fluoride, and trifluralin) in soil columns. The 1H water distribution studies demonstrate that NMR microimaging can provide unique detail regarding the nature and location of water in soils. Image distortion (magnetic susceptibility) was observed for soil samples low in water (20,28% by weight) and that contained an iron content of 0.73 to 0.99%. Highly resolved images were obtained for the organic-rich soil (Croatan sample) and also facilitated the analysis of bound and unbound soil water through varying spin echo times. The contaminant studies with 19F NMR demonstrated that preferential flow processes can be observed in soil cores in as little as 16 h. Studies with hexafluorobenzene produced the highest quality images whereas the definition decreased over time with both trifluralin and sodium fluoride as the compounds penetrated the soil. Nonetheless, both 1H and 19F NMR microimaging techniques demonstrate great promise for studying soil processes. [source] Amiodarone Attenuates Fluoride-induced Hyperkalemia in VitroACADEMIC EMERGENCY MEDICINE, Issue 2 2003Mark Su MD Abstract Poisoning by hydrofluoric acid or fluoride salts results in hypocalcemia, hypomagnesemia, and hyperkalemia with subsequent cardiac dysrhythmias. In previous studies, quinidine attenuated fluoride-induced hyperkalemia in vitro, and enhanced survival in animals. Like quinidine, amiodarone is a potassium channel blocker, although amiodarone is more familiar to clinicians due to its recent inclusion in advanced cardiac life support (ACLS) protocols. Objectives: This in-vitro study of human erythrocytes was designed to determine whether amiodarone could attenuate fluoride-induced hyperkalemia. Methods: Six healthy volunteers each donated 60 mL of blood on three occasions. Each specimen was divided into 12 tubes, incubated at 37°C, and oxygenated with room air. An aqueous sodium fluoride (F,) solution was added to tubes 1,9. Incremental amounts of quinidine were added to tubes 1,4 (Q1,Q4) to attain calculated concentrations of 0.73 ,g/mL, 1.45 ,g/mL, 2.9 ,g/mL, and 5.8 ,g/mL, respectively. Incremental amounts of amiodarone were added to tubes 5,8 (A1,A4) to attain calculated concentrations of 0.38 ,g/mL, 0.75 ,g/mL, 1.5 ,g/mL, and 3.0 ,g/mL, respectively. Tubes 9,12 were controls for each of F,, amiodarone, quinidine alone, and no additive, respectively. Extracellular potassium concentration ([K+]) was followed, and an objective endpoint was defined as the rise in potassium concentration at 6 hours. Results: Fluoride produced a significant change in [K+] by 6 hours in all samples. Quinidine produced a J-shaped curve in its ability to attenuate the rise in [K+], with only one concentration, Q3, demonstrating significance versus tube 9 (control). Amiodarone also demonstrated a J-shaped dose,response effect, with statistical significance at A1, A2, and A3 versus tube 9 (control). There was no significant difference among the effective concentrations (Q3, A1, A2, and A3) of both drugs. Conclusions: In this in-vitro model using human blood, amiodarone and quinidine both attenuated F, -induced hyperkalemia. Further study is indicated to determine whether amiodarone enhances survival in F, -poisoned animals. [source] The Effect of NaF In Vitro on the Mechanical and Material Properties of Trabecular and Cortical BoneADVANCED MATERIALS, Issue 4 2009Philipp J. Thurner High doses of sodium fluoride in bones lead to severe softening, by weakening interfacial properties between the inorganic minerals and the organic components, while leaving mineralization unchanged. This leads to reduction of microdamage and associated stress-whitening pointing to a change in failure mode. Accordingly, elastic modulus, failure stress, and indentation-distance increase are decreased, whereas failure strain is increased. [source] Reaction characteristics of a tooth-bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorineINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2005Y. Tanizawa This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth-bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X-ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X-ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two-dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet-analytical method, which is simply based on the difference in solubility of the two components. [source] Reaction characteristics of a tooth-bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorineINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2005Y. Tanizawa This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth-bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X-ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X-ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two-dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet-analytical method, which is simply based on the difference in solubility of the two components. [source] Proteomics analysis of liver samples from puffer fish Takifugu rubripes exposed to excessive fluoride: An insight into molecular response to fluorosisJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 1 2010Jian Lu Abstract Comparative proteomics was performed to identify proteins in the liver of Takifugu rubripes in response to excessive fluoride exposure. Sixteen fish were randomly divided into a control group and an experimental group. The control group was raised in soft water alone (F, = 0.4 mg/L), and the experimental group was raised in the same water with sodium fluoride at a high concentration of 35 mg/L. After 3 days, proteins were extracted from the fish livers and then subjected to two-dimensional polyacrylamide gel electrophoresis analysis. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to identify the proteins that were differentially expressed from the two groups of fish. Among an average of 816 and 918 proteins detected in the control and treated groups, respectively, 16 proteins were upregulated and 35 were downregulated (P < 0.01) in the fluoride-treated group as compared with those in the control group. Twenty-four highly differentially expressed proteins were further analyzed by MALDI-TOF/TOF-MS, and eight were identified by Mascot. These eight proteins include disulfide isomerase ER-60, 4SNc-Tudor domain protein, SMC3 protein, Cyclin D1, and mitogen-activated protein kinase 10, as well as three unknown proteins. Consistent with their previously known functions, these identified proteins seem to be involved in apoptosis and other functions associated with fluorosis. These results will greatly contribute to our understanding of the effects of fluoride exposure on the physiological and biochemical functions of Takifugu and the toxicological mechanism of fluoride causing fluorosis in both fish and human. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:21,28, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20308 [source] The effect of a dentifrice and mouth rinse combination containing amine fluoride/stannous fluoride on plaque and gingivitis: a 6-month field studyJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2005S. Paraskevas Abstract Aim: To examine the effect of amine fluoride/stannous fluoride (AmF/SnF2)-containing dentifrice and mouth rinse on plaque formation and gingivitis as compared with habitual oral hygiene procedures with a regular sodium fluoride (NaF) dentifrice. Material and Methods: In total, 22 general practices participated in this research project. The participants (N=281) were randomly assigned into two groups: the test group received an AmF/SnF2 dentifrice,mouth rinse combination and the control group received a NaF-containing dentifrice. The patients were requested to brush twice daily for approximately 2 min. The subjects of the test group had to rinse additionally in the evening for 30 s with 10 ml of the mouth rinse. Results: Both groups started with comparable scores of plaque, bleeding and staining. At 6 months, the plaque scores were 0.95 for the AmF/SnF2 group and 0.99 for the NaF group (decrease of 16% and 10%, respectively). Bleeding scores, although significantly different from baseline, did not show differences between the two regimes. At the end of the experimental period, the overall staining was more pronounced in the AmF/SnF2 group (41%) than the NaF group (26%). Both plaque reduction and increase in staining seemed to be correlated to the amount of mouth rinse used in the test group. Conclusion: In instruction-resistant patients recruited from dental practices, the combined use of AmF/SnF2 did not decrease gingivitis at a significant level in comparison with the regular regime of two times daily brushing with an NaF-containing dentifrice. However, the above-mentioned combination resulted in greater plaque reduction than that observed with the use of the conventional dentifrice. When used according to the manufacturer's instructions, this effect on plaque scores was more pronounced. [source] Effect of an amine-fluoride-triclosan mouthrinse on plaque regrowth and biofilm vitalityJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2002Nicole B. Arweiler Abstract Background: The purpose of this double-blind, prospective, latin-square crossover randomised study was to examine the efficacy of a mouthrinse solution containing a combination of triclosan, amine fluoride and sodium fluoride on supragingival plaque regrowth compared to a placebo and a chlorhexidine solution. Methods: 12 volunteers refrained after professional oral prophylaxis from all mechanical hygiene measures for the following 96 h and rinsed instead cross-over in a randomised order with either chlorhexidine dicluconate (0.2%, positive control), a verum solution (0.5% amine fluoride, 0.028% sodium fluoride, 0.03% triclosan) or a placebo solution. The plaque index was assessed after 24 and 96 h (PI 1, PI 2) and the plaque area (PA) photographed and calculated after 96 h of undisturbed plaque regrowth. Moreover plaque samples were taken after 24 and 96 h and examined with the vital fluorescence technique to assess the vitality of the biofilm microbiota (VF 1, VF 2). Results: The amine-fluoride-triclosan solution reduced the clinical parameters (PI and PA) as well as the vitality of the plaque flora (VF) significantly when compared to the placebo solution. The verum reached a 36.5% (p<0.05) and a 39.8% reduction (p<0.0001) in PI 1 and PI 2, respectively, concomittant with a reduction of 23.8% and 32.2% (p<0.001) in VF 1 and VF 2 and of 46.9% (p<0.0001) in PA at day 4. This was less than the reductions found with the positive control, i.e., the 0.2% chlorhexidine solution (54.2% and 71.1% reduction in PI 1 and PI 2, 40.0% and 53.4% in VF 1 and VF 2 and 71.5% in PA). However, significant differences between both active solutions were only established for PI 2 and PA. Conclusion: During 4-day plaque regrowth the amine-fluoride-triclosan product displayed a significant antibacterial and plaque-reducing action in comparison to the control. Zusammenfassung Hintergrund: Der Zweck dieser prospektiven, gekreuzten, randomisierten Doppeltblindstudie war die Überprüfung der Effektivität einer Mundspüllösung, die eine Kombination von Triclosan, Aminfluorid und Natriumfluorid enthielt, auf die Neuetablierung der supragingivalen Plaque im Vergleich zu einem Placebo und einer Chlorhexidinlösung. Methoden: 12 Probanden wurde nach einer professionellen Prophylaxe jegliche mechanische Hygiene für die folgenden 96 Stunden untersagt. Sie spülten dafür überkreuzt in einer zufälligen Reihenfolge entweder mit Chlorhexidindiglukonat (0.2%, positive Kontrolle), einer Versuchslösung (0.5% Aminfluorid, 0.028% Natriumfluorid, 0.03% Triclosan) oder einer Placebolösung. Der Plaque-index wurde nach 24 Stunden und 96 Stunden erhoben (PI 1, PI 2). Die Plaquefläche (PA) wurde fotografiert und berechnet nach 96 Stunden des ungestörten Plaquewachstums. Zusätzlich wurden Plaqueproben nach 24 und 96 Stunden entnommen und mit der Vitalfluoreszenztechnik die Vitalität der Mikroflora des Biofilms bestimmt (VF 1, VF 2). Ergebnisse: Die Aminfluorid-Triclosan-Lösung reduzierte die klinischen Parameter (PI und PA) sowie die Vitalität der Plaqueflora (VF) signifikant, im Vergleich mit der Placebolösung. Die Versuchslösung erreichte eine 36.5%ige (p<0.05) und eine 39.8%ige Reduktion (p<0.001) bei PI 1 und PI 2, verbunden mit einer Reduktion von 23.8% und 32.2% (p<0.01) bei VF 1 und VF 2 und 46.9% (p<0.0001) bei PA am Tag 4. Dies war geringer als die Reduktionen, die mit der positiven Kontrolle gefunden wurden, d.h. mit der 0.2%igen Chlorhexidin-Lösung (54.2% und 71.1% Reduktion bei PI 1 und PI 2, 40.0% und 53.4% bei VF 1 und VF 2 sowie 71.5% bei PA). Jedoch wurden signifikante Differenzen zwischen beiden aktiven Lösungen nur bei PI 2 und PA gefunden. Zusammenfassung: Während eines 4tägigen Plaquewachstums zeigte das Aminfluorid-Triclosan-Produkt eine signifikante antibakterielle und plaquereduzierende Wirkung im Vergleich zu der Kontrolle. Résumé Origine: Le but de cette étude randomisée, croisée, prospective en double aveugle a été d'examiner l'efficacité d'une solution contenant une association de fluorure d'amine, de fluorure de sodium et de triclosan sur l'accumulation de la plaque dentaire sus-gingivale comparée à un placebo et à une solution de chlorhexidine (CHX). Méthodes: Après un nettoyage professionnel, 12 volontaires ont arrêté toutes mesures d'hygiène buccale pendant 96 h. Ils se sont rinçés de manière randomisée et croisée avec du digluconate de CHX 0.2%, une solution verum (fluorure d'amine 0.5%, fluorure de sodium 0.028% et triclosan 0.03%) ou une solution placebo. L'indice de plaque a été mesurée après 24 h (Pli 1) et 96 h (Pli 2) et la zone de plaque (PA) photographiée et calculée après 96 h. Des échantillons de plaque dentaire ont été prélevés après 24 h (VF 1) et 96 h (VF 2) et examinés par la technique de vitalité de fluorescence, pour mesurer la vitalité de la flore du biofilm. Résultats: La solution flurorure d'amine/triclosan réduisait significativement les paramètres cliniques (Pli et PA) ainsi que la vitalité de la flore (VF) comparée à la solution placebo. Le vérum atteignait des réductions respectives de 37% (p<0.05) et 40% (p<0.0001) des Pli 1 et Pli 2 concomitantes avec une réduction de 24 et 32% (p<0.001) de VF 1 et VF 2 et de 47% (p<0.0001) de PA au jour 4. Ceci était inférieur aux réductions trouvées dans le contrôle positif, c.-à-d. la CHX 0.2% (54 et 71% de réduction de Pli 1 et Pli 2, 40 et 53% de VF 1 et VF 2, et 72% de PA). Cependant, les différences significatives entre les deux solutions actives ont été mises en évidence uniquement pour Pli2 et PA. Conclusion: Durant cette courte croissance de la plaque dentaire, le produit fluorure d'amine/triclosan montrait une action antibactérienne et anti-plaque supérieure à celle du contrôle. [source] Fluoride release and uptake characteristics of aesthetic restorative materialsJOURNAL OF ORAL REHABILITATION, Issue 8 2002N. Attar Summary The aims of this study were firstly to investigate the fluoride-releasing characteristics of two composite resins (Tetric and Valux Plus), two polyacid-modified resin composites (Compoglass and Dyract), and conventional glass,ionomer cement (Ceramfil ,). The second aim was to assess the fluoride uptake and subsequent release from the same range of materials. Fifteen discs (6 mm diameter and 1·5 mm height) were prepared for each material. Each disc was immersed in 4 ML of deionized water within a plastic vial. The release of fluoride was measured daily at 1, 2, 3, 4, 5, 15, 30 and 60 days. After daily fluoride release was measured for 60 days, samples were refluoridated in 1000-ppm sodium fluoride (NaF) solutions (pH 6·6) for 10 min and fluoride release was measured daily for a total of 5 days. The release of fluoride from aesthetic restorative materials was measured by using specific fluoride electrode and an ionanalyser. Results were statistically analysed by two-way repeated measure ANOVA and Duncan's multiple range test. The results revealed that all fluoride-containing materials (Ceramfil ,, Compoglass, Dyract, Tetric) released fluoride initially and the release was greatest at the first day. At any time during the test period Ceramfil , released the most and Valux Plus did not release any detectable fluoride (P < 0·01). Sample exposures to 1000 ppm NaF solution increased the 24-h fluoride release from all fluoride-containing materials. This difference lasted only 24,48 h after exposure. Ceramfil , had a tendency to recharge not seen with the other materials (P < 0·05). [source] Physiological characteristics of selenite uptake by maize roots in response to different pH levelsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2010Lianhe Zhang Abstract In selenite solutions, H2SeO3, HSeO, and SeO<$>_3^{2-}<$> are in equilibrium in proportions that vary with solution pH. The physiological characteristics of selenite uptake were studied with excised roots of maize (Zea mays L.) seedlings at pH 3.0, 5.0, and 8.0. The results showed that 0.10 mM 2,4-dinitrophenol (DNP), 1.0 mM sodium fluoride (NaF), and a temperature of 4°C inhibited selenite uptake by maize roots by 16%, 20%, and 23% at pH 3.0, by up to 80%, 79%, and 78% at pH 5.0, and by 5%, 9%, and 16% at pH 8.0. Hence, selenite may enter roots at pH 5.0 in an energy-dependent manner, in contrast to pH 3.0 and 8.0. The uptake kinetics for selenite were determined for excised roots of maize, and the curves were linear at pH 3.0 and 8.0, but saturated at pH 5.0, showing that carrier-mediated uptake of selenite occurred at pH 5.0, but not at pH 3.0 or 8.0. Further studies showed that HgCl2 and AgNO3 inhibited selenite uptake separately by 81% and 76% at pH 3.0 and indicated that selenite was absorbed by maize roots through aquaporins at pH 3.0. At pH 8.0, anion-channel inhibitors only inhibited a small fraction of selenite uptake, indicating that the major absorption pathway of SeO<$>_3^{2-}<$> species into roots was not absorbed passively through anion channels, but might involve other processes. According to these results, it is proposed that selenite uptake occurs via different mechanisms depending on its species in solution in response to pH levels. [source] Effects of fluorides on Candida albicansORAL DISEASES, Issue 4 2008S Flisfisch Aims:, To assess whether a short exposure of Candida albicans to commonly used fluorides would affect growth, cell surface hydrophobicity, and adherence to buccal epithelial cells. Methods:,Candida albicans ATCC 90028 and 11 clinical isolates were used. Minimal inhibitory concentrations (MICs) of sodium fluoride (NaF) and of an amine fluoride,/,stannous fluoride combination (AmF,/,SnF2) were determined. Yeasts were exposed to MICs of tested agents for 1 h. Subsequently, their growth was recorded spectrophotometrically. Their cell surface hydrophobicity was assessed with n -hexadecane. Adherence to buccal epithelial cells was determined microscopically. Phosphate buffered saline (PBS) and chlorhexidine digluconate (CHX) served as controls. All results were analyzed by one-way ANOVA. Results:, MICs of AmF,/,SnF2 and CHX varied between 1 and 4 ,g ml,1, whereas those of NaF were 15 000 ,g ml,1. Statistically significant growth inhibition was detected after AmF,/,SnF2 (OD24 h ± SD 0.457 ± 0.059) and CHX (0.175 ± 0.065) in comparison with PBS (0.925 ± 0.087) and NaF (0.813 ± 0.081). All strains demonstrated uniform behavior. Only minor changes in cell surface hydrophobicity and adherence to buccal epithelial cells (BEC) were detected. Conclusion:, Growth inhibition of AmF,/,SnF2 was comparable with that of CHX whereas NaF had a weaker effect. Exposure to the fluorides did not seem to alter the cell surface hydrophobicity nor adherence to BEC. [source] Oestradiol Protects Against the Harmful Effects of Fluoride More by Increasing Thiol Group Levels than Scavenging Hydroxyl RadicalsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2009Anna Dlugosz Interactions between xenobiotics and oestrogens need to be investigated, especially as many chemicals interact with the oestrogen receptor. It is still unknown whether free radical-generating xenobiotics can influence the antioxidative ability of oestradiol (E2). In an in vitro examination of human placental mitochondria, thiobarbituric active reagent species (TBARS), hydroxyl radical (,OH) generation and protein thiol (,SH) groups were detected. 17,-E2 was examined in physiological (0.15,0.73 nM) and experimental (1,10 µM) concentrations and sodium fluoride (NaF) in concentrations of 6,24 µM. E2 in all the concentrations significantly decreased lipid peroxidation measured as the TBARS level, in contrast to NaF, which increased lipid peroxidation. Lipid peroxidation induced by NaF was decreased by E2. The influence of E2 on ,OH generation was not very significant and depended on the E2 concentration. The main mechanism of E2 protection in NaF exposure appeared to be connected with the influence of E2 on thiol group levels, not ,OH scavenging ability. The E2 in concentrations 0.44,0.73 nM and 1,10 µM significantly increased the levels of ,SH groups, in contrast to NaF, which significantly decreased them. E2 at every concentration reversed the harmful effects of NaF on ,SH group levels. No unfavourable interactions in the influence of E2 and NaF on TBARS production, ,OH generation, or ,SH group levels were observed. The results suggest that postmenopausal women could be more sensitive to NaF-initiated oxidative stress. [source] Expression, purification, crystallization and preliminary X-ray diffraction analysis of dihydrodipicolinate synthase from Bacillus anthracis in the presence of pyruvateACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009Jarrod E. Voss Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step in the lysine-biosynthesis pathway in bacteria, plants and some fungi. In this study, the expression of DHDPS from Bacillus anthracis (Ba -DHDPS) and the purification of the recombinant enzyme in the absence and presence of the substrate pyruvate are described. It is shown that DHDPS from B. anthracis purified in the presence of pyruvate yields greater amounts of recombinant enzyme with more than 20-fold greater specific activity compared with the enzyme purified in the absence of substrate. It was therefore sought to crystallize Ba -DHDPS in the presence of the substrate. Pyruvate was soaked into crystals of Ba -DHDPS prepared in 0.2,M sodium fluoride, 20%(w/v) PEG 3350 and 0.1,M bis-tris propane pH 8.0. Preliminary X-ray diffraction data of the recombinant enzyme soaked with pyruvate at a resolution of 2.15,Å are presented. The pending crystal structure of the pyruvate-bound form of Ba -DHDPS will provide insight into the function and stability of this essential bacterial enzyme. [source] Solubilizing Sodium Fluoride in Acetonitrile: Synthesis, Molecular Structure, and Complexation Behavior of Bis(organostannyl)methyl-Substituted Crown Ethers,CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2007Gregor Reeske Dr. Abstract The synthesis of the crown-ether-substituted bis(organostannyl)methanes Ph3SnCH2Sn(Ph2)-CH2 -[16]crown-5 (1) and Ph2ISnCH2Sn(I)(Ph)-CH2 -[16]crown-5 (2) is reported. Both compounds have been characterized by elemental analyses, 1H, 13C, 19F, and 119Sn,NMR spectroscopy, and in the case of compound 2 also by electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analysis revealed for the aqua complex 2,H2O trigonal,bipyramidal-configured tin atoms with intramolecular Sn(1)O(1) and Sn(2)O(1W) distances of 2.555(2) and 2.440(3),Å, respectively. The water molecule is trapped in a sandwich-like fashion between the crown ether oxygen atoms O(2) and O(4) and the Sn(2) atom. NMR spectroscopy unambiguously proved the ability of compound 2 in acetonitrile to overcome the high lattice energy of sodium fluoride and to complex the latter under charge separation. [source] A school-based fluoride mouth rinsing programme in Sarawak: a 3-year field studyCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 4 2010Catherine Jean-Ai Chen Chen CJ-A, Ling KS, Esa R, Chia JC, Eddy A, Yaw SL. A school-based fluoride mouth rinsing programme in Sarawak: a 3-year field study. Community Dent Oral Epidemiol 2010; 38: 310,314. © 2010 John Wiley & Sons A/S Abstract,,, Background:, This study was undertaken to assess the impact of fluoride mouth rinsing on caries experience in a cohort of schoolchildren 3 years after implementation. Methods:, 270 children aged 8,9 years from four schools in Sarawak were selected at baseline. Baseline data was collected to ensure that the selected schools did not differ significantly. Children from two schools rinsed with 0.2% sodium fluoride under supervision, while those from the other schools did not. Results:, After 3 years, 242 schoolchildren remained in the study. At the end of the study, the mean DMFT for the test group was 2.3 (95% CI, 1.93,2.67) while the mean DMFT for the control group was 4.01 (95% CI, 3.39,4.63). The mean DMFS for the test group was 3.40 (95% CI, 2.68,4.12) while the mean DMFS for the control group was 6.67 (95% CI, 5.47,7.87). After 3 years, 24.2% of those in the test group remained caries free compared to 11.5% in the control group. The risk of developing caries decreased 0.52 times among the children from the ,test' group exposed to the fluoride mouth rinsing programme as compared to the unexposed ,control' group (RR = 0.48, 95% CI, 0.26,0.85). Discussion and conclusion:, The findings show that a school-based weekly 0.2% sodium fluoride mouth rinsing programme is an effective caries preventive measure and should be implemented in fluoride-deficient areas as a means of reducing the prevalence of dental caries in these communities. [source] Caries management for institutionalized elders using fluoride and chlorhexidine mouthrinsesCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 5 2004Chris C. L. Wyatt Abstract , Objectives:, The effectiveness of either a 0.2% neutral sodium fluoride (NaF) solution or a 0.12% chlorhexidine (CHX) solution as a daily mouthrinse for controlling caries was tested against a placebo rinse in this 2-year randomized clinical trial among elders in long-term care (LTC) facilities. Methods:, At baseline, 369 recruits were examined clinically for caries and allocated randomly to one of the mouthrinse groups. Results:, After 2 years, 116 participants remained in the trial. The prevalence of caries and the dental status of the groups were similar at baseline and after 2 years. On average, each group lost less than one tooth per person, but the fluoride group compared with the others had significantly less caries and significantly more reversals from carious to sound dental surfaces at the end of the trial. Conclusions:, We conclude that 0.2% neutral NaF mouthrinse every day does reduce the incidence of caries among elders in LTC facilities. [source] | ||||||||||||||||