Sodium Fluoride Solution Research Articles

Mineral nutrition of buckwheat in fluoride polluted soil: case study in pot experiment

The research aimed to establish an optimal and safe level of mineral nutrition for buckwheat grown in the fluoride contaminated soil by defining yield and chemical composition of buckwheat grown on acidic soddy-podzolic soil under different levels of fertilization, and assessing the possibility of reducing fluoride phytotoxicity. The mechanisms of plant uptake of fluoride may be influenced by interaction in nutrient uptake by plant. Sodium fluoride solution was applied at the rate of 100 mg per 1 kg of soil mass. Two different experiments were studied under controlled conditions: the first experiment with increasing doses of ammonium nitrate, and the second experiment with increasing doses of orthophosphoric acid. Increase of N fertilization resulted in an increase in the concentration of fluoride in the tissues of buckwheat and lowers yields of plants, while application of P reduced uptake of fluoride and increased productivity of buckwheat. In fluoride contaminated soil the chemical composition of buckwheat was affected by synergism and antagonism of individual elements during absorption by plants. A protective mechanism of buckwheat against negative effect of fluoride was due to its ability to activate metabolism regulating the flow of individual elements in tissue that reduces the adverse impact of pollutant.

Surface roughness and chemical composition changes of resin-modified glass ionomer immersed in 0.2% sodium fluoride solution

Background/purposeGlass ionomers undergo degradation when exposed to fluoride, which changes the physico-chemical characteristics of the materials. The purpose of this study was to evaluate the surface changes of resin-modified glass ionomer (RMGI) when immersed in a sodium fluoride (NaF) solution according to pH and time. Materials and methods120 RMGI specimens were prepared, and 30 specimens were placed in four types of storage solutions for four weeks; pH 7 artificial saliva with or without 0.2% NaF (As7 and NaF7), pH 5 artificial saliva with or without 0.2% NaF (As5 and NaF5). Interferometry and microscopy were performed to evaluate the surface roughness and topography, while spectroscopy was used to analyze the chemical composition changes. ResultsRougher topography and increased roughness was exhibited in NaF groups, owing to the disintegration of the polysalt matrix. Reduced Sr and F was exhibited in all groups, whereas NaF group showed a decrease in Al and inorganic components. ConclusionThis study suggest that excessive use of fluoride therapy could lead to severe degradation of RMGI.

A mild anion-exchange HPLC method for analysis of [18F]sodium fluoride solution for injection

A mild HPLC method for the quality control of [18F]sodium fluoride solution for injection was developed. The method used anion exchange column for separation, UV and online radio-detectors for fluoride content and fluorine-18 determination. A mixture of 100 mM sodium acetate and 25 mM sodium chloride was chosen as mobile phase. The method was validated for system suitability, specificity, fluoride concentration and radiochemical purity determination with good linearity, accuracy and precision. The good robustness of the system was also verified, enabling routine analysis of fluoride content and radiochemical purity of the [18F]sodium fluoride product.

Using Shungite in Water Defluoridation by Galvanocoagulation

Fluorine is a natural component of many sources of drinking water. An excess of fluorine in drinking water leads to metabolic disturbances in bone tissues. In this context, the International Drinking Water Quality Standards recommend adhering to a fluoride content of drinking water of no more than 1.5 mg/dm3. If this value is exceeded, water requires defluoridation. In this work, defluoridation by galvanocoagulation in a drum-type galvanocoagulator was studied. The half-cells of the galvanic couple were aluminum and shungite mined at the Polezhaevskii deposit, Karelia, Russia. The occurring electrochemical processes result in anodic dissolution of aluminum to form the corresponding hydroxides. The fluoride ion forms aluminofluoride complexes with them, which are adsorbed on freshly formed hydroxide flakes. The ratio between the half-cells of the galvanic couple as a significant factor of controlling the process efficiency was studied. It was shown that the fluoride ions were removed most completely at an aluminum : schungite ratio of 1 : 1.5. Experiments on model aqueous solutions of sodium fluoride detected a significant dependence of the process on the initial pH value. The experimental results enabled one to choose a mode of defluoridation of water with various fluoride contents. By the example of treatment of artesian water with a fluoride content of 9.1 mg/dm3 from Mashevka, Poltava oblast, Ukraine, a high efficiency of the studied process was demonstrated: the fluoride ion content of the water treated for 5 min decreased to 0.9 mg/dm3. In addition, when using shungite as a half-cell of the galvanic couple, its disinfecting effect was observed: whereas the initial content of coliform bacteria was 700 in 100 cm3, they were absent in the treated water. The redox potential was also reduced from 340 to 255 mV, which is noteworthy because this parameter has recently received considerable attention as being one of the most important parameters of water in its interaction with the human body.

Synthesis and Characterization of Fluoridated Silver Nanoparticles and Their Potential as a Non-Staining Anti-Caries Agent.

ObjectivesThe first objective of this study was to prepare sodium fluoride (NaF) solution with various concentrations of polyethylene glycol-coated silver nanoparticles (PEG-AgNPs). The second objective was to study the antibacterial activity against Streptococcus mutans and the tooth-staining effect of the solution.MethodsPEG-AgNPs were prepared via the one-step chemical reduction of silver acetate with thiolated polyethylene glycol. The PEG-AgNPs were characterized with ultraviolet-visible spectrometry and transmission electron microscopy. The half maximal inhibitory concentration (IC50) for the PEG-AgNPs against Streptococcus mutans and human gingival fibroblasts (HGF-1) were determined. The staining effect on dentin and enamel for the 2.5% NaF solutions with PEG-AgNPs at 12,800, 6400, 1600, and 400 ppm was investigated using digital spectrophotometry. The IC50 of the fluoridated silver nanoparticles against Streptococcus mutans were measured.ResultsThe PEG-AgNPs have an average diameter of 2.56±0.43 nm and showed excellent stability at high ionic strength (2.5% NaF) for 18 months. The IC50 of PEG-AgNPs against Streptococcus mutans was found to be 21.16±1.08 ppm silver, which was half of IC50 against HGF-1 cells (42.36±1.12 ppm), providing a working range to kill bacteria with no harm to human cells. The formulations with different concentrations of PEG-AgNPs showed no significant staining of teeth. Combining PEG-AgNPs with NaF significantly expanded the therapeutic window against Streptococcus mutans by reducing its IC50.ConclusionA biocompatible solution of NaF with PEG-AgNPs was developed. Because it has antibacterial activity against Streptococcus mutans and no tooth-staining effect, it can be used as an anti-caries agent.

Inimical Effects of Sodium Fluoride on Ovarian Weight and Relative Tissue Weight Index of Adult Albino Rats


 
 
 Objective: To determine the impacts of sodium fluoride on ovarian weight and relative tissue weight index (RTWI) of adult Wistar albino rats. Study Design: Comparative study. Place and Duration of Study: This experimental study was performed at the Department of Anatomy, at Shaikh Zayed Postgraduate Medical Institute, Lahore from 25th November to 24th December 2016. Materials and Methods: Forty-four adult female albino Wistar rats were selected randomly for this study. They were segregated into 4 groups, each comprised of eleven rats. Group A was control, group B was low dose experimental, group C was medium dose experimental and group D was high dose experimental. The control group received distilled water whereas low, medium and high dose experimental groups received 100mg/L, 200mg/L and 300mg/L sodium fluoride solution respectively. The animals were weighed before and after experiment. At 31st and 32nd day, dissection was done, ovaries were removed and evaluated for ovarian tissue weight and RTWI. Results: The mean weight and RTWI of paired ovaries among the experimental groups were decreased. The differences among groups were statistically significant. Conclusion: The present study confirms that sodium fluoride has detrimental dose dependent effects on ovarian weight and RTWI of adult albino rats.
 
 

<p>Remineralising Dentine Caries Using Sodium Fluoride with Silver Nanoparticles: An In Vitro Study</p>

ObjectiveTo investigate the remineralizing and staining effects of sodium fluoride (NaF) solution with polyethylene glycol-coated silver nanoparticles (PEG-AgNPs) on artificial dentine caries.Materials and MethodsDemineralized human dentine blocks were allocated to three groups. The blocks in group 1 underwent a topical application of a 12% silver diamine fluoride (SDF, 14,150 ppm fluoride) solution. The blocks in group 2 received a topical application of a 2.5% NaF (11,310 ppm fluoride) with PEG-AgNPs (400 ppm silver). The blocks in group 3 received deionized water. All blocks were subjected to pH cycling for 8 days. The surface morphology and cross-sectional features were investigated using scanning electron microscopy (SEM). The color parameters, crystal characteristics, lesion depth, and collagen degradation of the blocks were assessed using digital spectrophotometry, X-ray diffraction (XRD), micro-computed tomography, and spectrophotometry with a hydroxyproline assay, respectively.ResultsThe SEM showed that dentine collagen was exposed in group 3 but not in groups 1 and 2. The mean lesion depths in groups 1 to 3 were 118±7 µm, 121±14 µm, and 339±20 µm, respectively (groups1,2<3; p<0.001). The data indicated that fluoridated PEG-AgNPs introduced no significant color effect on dentine, but SDF caused distinct discoloration. The XRD indicated that silver chloride was formed in group 1, and fluorapatite was detected in groups 1 and 2. The concentration of hydroxyproline liberated from collagen was significantly less in groups 1 and 2 than in group 3.ConclusionThe use of NaF solution with PEG-AgNPs can remineralize artificial dentine caries and inhibit collagen degradation without causing significant tooth staining.

The state of oxidative-antioxidant homeostasis under the influence of subtoxic doses of sodium fluoride

The objective of the study was to study the state of oxidative-antioxidant homeostasis under the conditions of the formation of experimental fluoride intoxication.24 white rats of the Wistar population were daily injected with sodium fluoride solution (20 mg/kg of animal weight). The continuation of intragastric xenobiotic intake was 1.5 months. The control group was monitored for 2 weeks toanalyse their condition. After 2 weeks, and The study program was conducted after 2 weeks when healthy mature (3 months) males weighing 180-200 grams were selected . At the end of the experiment, the control and experimental groups were clogged by decapitation. Evaluation of oxidative-antioxidant homeostasis was doneon the basis of the following indicators: the intensity of biochemiluminescence (BCL) of homogenates of internal organs and blood serum, the blood levels of SH-groups, glutathione, haptoglobin, diene conjugates (DC), malondialdehyde (MDA), cysteine, catalase activity, peroxidase, ceruloplasmine, glutathione peroxidase, superoxide dismutase. Vitamin C was determined in the adrenal glands. Analyzing the effect of fluoride intoxication on the state of oxidative and antioxidant system, it was shown that stimulation of free radical lipid peroxidation, the accumulation of peroxides, hydroperoxides, free radicals and inhibition of the antioxidant system are characteristic in this process. The obtained results confirm that all these mechanisms underlie the formation of structural and metabolic mechanisms of the pathogenesis of fluoride intoxication.

Fluoride release and fluoride-recharging ability of three different sealants.

We aimed to determine the fluoride release and fluoride-recharging ability of a sealant containing surface pre-reacted glass (S-PRG) ionomer filler particles (BeautiSealant) with a fluoride-releasing resin sealant (Helioseal F), and a glass-ionomer sealant (Fuji VII). Forty-eight disc-shaped specimens of each material were immersed in deionized water to determine the fluoride release utilizing a fluoride ion-selective electrode. After 21 days, 8 specimens were soaked in 0.22% Sodium Fluoride solution for 2 min; 8 specimens were coated with 1.23% Acidulated Phosphate Fluoride (APF) gel for 4 min, and the fluoride-recharging ability was evaluated for 40 days. Data were analyzed using one way-ANOVA and Bonferroni post hoc tests. Total fluoride release over the 21-day period was: Fuji VII > BeautiSealant > Helioseal F, (P = 0.000). After refluoridation of the specimens with 0.22% Sodium Fluoride solution, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal (P = 0.000). After exposure to 1.23% APF gel, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal F (P = 0.000). Glass ionomer-based sealants (Fuji VII) exhibited higher initial fluoride release whilst the surface pre-reacted glass-ionomer filler containing sealant (BeautiSealant) demonstrated superior fluoride recharging properties.

Delayed Tooth Replantation after Root Surface Treatment with Papain and Sodium Fluoride in Rats: A Histological and Histomorphometrical Evaluation.

The aim of this study was to examine the histological effect of papain and sodium fluoride in delayed replantation of rat incisor teeth on the repair process. Forty upper incisors of Wistar rats were randomly assigned to four groups (n=10). In group I, the dental papilla and the pulp tissue of extracted teeth were removed before immediate replantation in their sockets. In the other groups, the extracted teeth were maintained in dry storage for 60 min and subjected to different root surface treatments. In group II, the teeth were immersed in 10% papain for 20 min, scrubbed with gauze soaked in saline for 1 min, and immersed in a 2% acidulated-phosphate sodium fluoride solution for 20 min. In group III, the teeth were immersed in saline for 20 min, scrubbed with gauze soaked in saline for 1 min, and immersed in a 2% acidulated-phosphate sodium fluoride solution for 20 min. In group IV, root surface treatment was not applied. The root canals were treated and filled with a calcium hydroxide paste and the teeth were replanted. The animals were euthanized after 60 days and anatomic specimens containing the teeth were subjected to routine histochemical processing and staining with hematoxylin and eosin. The Kruskal-Wallis test was used, followed by the Dunn's test for multiple comparisons. Groups I and II had less inflammatory root resorption and total area of root resorption (P<0.05) than groups III and IV respectively. Based on this animal study, root surface treatment with papain and sodium fluoride in delayed tooth replantation showed greater efficacy in controlling inflammatory root resorption and may be a viable option for clinical application.

Chitosan Curcumin Film as a Sensor for Detection of O-Nitrophenol and Fluoride Ion Using Fluoresce Quenching Technique

Curcumin was immobilized in chitosan films fabricated by solvent casting method. The amount of curcumin immobilization was more when methanol was used as a solvent to dissolve curcumin than the butanol solvent. The maximum amount of curcumin immobilized per gram of chitosan film was 0.023 g. Immobilized curcumin was not released back in water even after prolong contact of the films with water. Fluorescence intensity of the films got quenched when these films were in contact with an aqueous solution of o-nitrophenol (ONP) and sodium fluoride (NaF). The extent of quenching depended on the concentration of these attributes. Fluorescence intensity was highly pronounced even when the concentration of ONP and fluoride (FL) was as low as 2.0 x 10–6 M and 2.5 x 10–5 M, respectively. UV-vis spectroscopy could not detect 2.5 x 10–6 M ONP; similarly, ion chromatography was not sensitive towards 2.5 x 10–5 M FL. Since the extent of quenching varies linearly with the concentration of ONP and FL in aqueous solution, the Stern-Volmer equation can be used for quantification of these.

Solubility of ammonium fluoride in aqueous sodium fluoride solutions of various concentrations from dilute to saturated at 298.15 K for fluorine recovery from wet-process phosphoric acid

Recovery of fluorine from wet-process phosphoric acid (WPA) to produce ammonium fluoride (NH4F) and sodium fluoride (NaF) provides an environmentally-friendly route to purify WPA and produce high value-added fluoride salt. The solubility data and the related electrolyte thermodynamics are essential for a rational separation design of pure NH4F from aqueous NaF solution by crystallization. In this contribution, the solubilities of NH4F in aqueous NaF solutions of different concentrations from dilute to saturated were systematically measured at 298.15 K using a dynamic synthesis method. Experimental results show that the presence of NaF in the solution could significantly decrease the solubility of NH4F due to the common-ion effect which was decreased by 72.4% when the molality of NaF was only around 0.015 mol/kg. The data can be used to determine the yield of NH4F and liquid composition in the vacuum evaporative crystallization of NH4F. The mean activity coefficients of NH4F at saturation were determined from the experimental solubility data and then correlated with the extended Debye-Hükel equation and the Pitzer model. With four adjustable parameters, both models are able to accurately calculate the experimental data over a wide range of salt concentrations. The average relative deviations between the experimental and calculated logarithm of mean activity coefficients of NH4F from the two models are 1.43% and 2.29%, respectively. The binary and ternary ionic parameters for the Pitzer model are found to be concentration dependent and the correlations of them as functions of ionic strength are proposed.

Synthesis of plate-like \u03b2-tricalcium phosphate nanoparticles and their efficiency in remineralization of incipient enamel caries

The purpose of this study was to synthesize nano-sized β-tricalcium phosphate (nano-TCP) particles and determine its concentration-dependent properties on incipient enamel caries lesions. Nano-TCP was synthesized as a wet chemical through a method using low concentration of precursors and low addition rate of calcium nitrate tetrahydrate as a second phase. Morphology and phase composition of the particles were analyzed by SEM, XRD, and EDXA techniques. Incipient enamel lesions were created in human premolars with an acidic buffer. The teeth were then incubated in aqueous dispersions of nano-TCP as remineralization solutions. Sodium fluoride solution and deionized water were used as positive and negative control groups, respectively. The quality and thickness of the remineralized layer on enamel were investigated using SEM. The data were statistically analyzed by analysis of variance (ANOVA) and post hoc Tukey’s test. The synthesized nano-TCP mostly consisted of porous platelet-like crystals of 50–100 nm thickness and pore diameters of 100–300 nm. SEM observation showed that a homogenous layer was formed on the surface of the enamels remineralized in nano-TCP solutions. The thickness of the mineralized layer was dependent on the incubation time and nano-TCP concentration.

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey’s tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey’s test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5); and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68). Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel.

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey's tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey's test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5); and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68). Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Osseointegration of titanium dental implant under fluoride exposure in rabbits: Micro-CT and histomorphometry study.

This study aims to investigate the influence of fluoride exposure on implant osseointegration. A total of 24 male New Zealand white rabbits were randomly divided into the control group and the fluoride exposure group. Rabbits in the control group were fed with tap water, while those in the fluoride exposure group were given 200mg/L sodium fluoride solution. After 2-month feeding, implants were inserted into the extraction socket immediately after extraction of rabbit mandibular anterior teeth. Four rabbits in each group were sacrificed to collect the implants samples at 1, 2, and 3months post-implantation, respectively. Radiographic and histomorphometry examinations were performed to evaluate the condition of implant osseointegration. Bone volume around the implants increased in a time-dependent manner in both groups. Micro-CT images illustrated that the bone mineral density (BMD) in the fluoride exposure group was significantly lower than that in the control group after implantation for 2 and 3months. The bone-implant contact ratio (BIC) in the fluoride exposure group was much lower than that of the control group at 3months post-implantation according to histomorphometry examination. In rabbit animal model, high fluoride exposure affected the quality of bone surrounding the implant and significantly reduced bone integration of the implant, especially in the late stage of osseointegration.

Патофизиологические механизмы иммунной реактивности печени в условиях длительного экспериментального воздействия на организм фторида натрия

В условиях непрерывного воздействия неблагоприятных факторов окружающей и производственной среды на человека особую актуальность приобретает изучение механизмов, поддерживающих гомеостаз организма. Длительное поступление фторидов в организм приводит к формированию хронической фтористой интоксикации, патогенез которой вызывает многочисленные споры и дискуссии. До сих пор недостаточно внимания уделяется изучению висцеральной патологии, обусловленной нарушениями иммунного статуса в условиях воздействия на организм соединений фтора. Практически отсутствуют исследования по изучению иммунной реактивности, определяющей морфофункциональный характер ответной реакции печени на ранних стадиях развития фтористой интоксикации. Цель работы - изучение действий патофизиологических механизмов иммунной реактивности печени при субхроническом действии на организм соединений фтора. Методика. Опыты проведены на 210 лабораторных крысах-самцах массой 180-220 г., разделенных на 2 группы: контрольную (n=80) и группу животных с субхроническим действием фторида натрия (n=130). Экспериментальные животные в течение 12 нед имели свободный доступ к водному раствору фторида натрия (концентрация 10 мг/л, что составляет суточную дозу фтора 1,2 мг/кг массы тела). Для изучения иммунологических и биохимических показателей забирали кровь из хвостовой вены через 1, 3, 6, 9, 12 нед от начала эксперимента. Для оценки состояния гуморального звена иммунитета определяли уровень сывороточных иммуноглобулинов (IgA, IgG, IgM) иммуноферментным анализом с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск). Уровень сывороточных цитокинов: TNF-α, IL-1β, 2, 4, 6, 10 определяли на анализаторе Multiskan EX методом иммуноферментного анализа с использованием наборов «Вектор Бест» (Новосибирск). Подсчет общего количества лейкоцитов произведен классическим способом в камере Горяева, анализ лейкоцитарной формулы - в окрашенных мазках периферической крови. Метаболические изменения оценивали по активности ферментов в ткани печени: щелочной фосфатазы (ЩФ), аланин- и аспартатаминотрансфераз (АЛТ, АСТ), лактатдегидрогеназы (ЛДГ), гаммаглутамилтранспептидазы (γ-ГТ). Активность ферментов определяли унифицированными методами с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск) на фотометре PM-750 (Германия). Гистологические исследования печени осуществляли после декапитации крыс, проводимой под эфирным наркозом. Результаты. Показано, что субхроническое воздействие фторида натрия сопровождается формированием внутриклеточных и внутрисосудистых повреждений печени. Активация медиаторов воспаления и развитие иммунологических нарушений в динамике эксперимента способствуют формированию системной воспалительной реакции, которая приводит к появлению стойких морфологических нарушений в печени и изменению активности ферментов основных метаболических путей. Заключение. Полученные результаты могут быть использованы при разработке и проведении профилактических мероприятий в условиях воздействия на организм высоких концентраций фтора с последовательным применением детоксикационной, иммуномодуляторной и органопротекторной коррекции. Studying mechanisms, which maintain the body homeostasis, is particularly important in the conditions of continuous impact of adverse environmental and manufacturing factors. Long-term exposure to fluorides leads to chronic fluoric intoxication, the pathogenesis of which is a subject of multiple controversy and discussions. Not enough attention is still paid to elucidating the visceral pathology associated with fluorine-induced immune disorders. There are virtually no studies of immune reactions that define the morphofunctional nature of the liver response to early stages of fluoric intoxication. Aim. To study pathophysiological mechanisms of hepatic immune reactivity in subchronic exposure of the body to fluorine compounds. Methods. Experiments were performed on 210 male rats weighing 180-220 g. The animals were divided into two groups: 1) control (n=80) and 2) subchronic exposure to sodium fluoride (n=130). The rats had free access to a 10 mg/l aqueous solution of sodium fluoride (daily dose, 1.2 mg/kg body weight) for 12 weeks. Blood was withdrawn from the caudal vein at 1, 3, 6, 9, and 12 weeks of the experiment for immunological and biochemical tests. Histological study of the liver was performed after decapitation of rats under ether anesthesia. Results. The subchronic exposure to sodium fluoride was associated with intracellular and intravascular damage of the liver. Activation of inflammatory mediators and development of immunological disorders during the experiment contributed to a systemic inflammatory reaction, which resulted in persistent morphological injuries of the liver and changes in enzyme activities in major metabolic pathways. Conclusion. The study results can be used for development and implementation of preventive measures against the effects of high fluorine concentrations, which would include a successive use of detoxification, immunomodulation and organ protection.

CONDITION OF HORMONAL STATUS OF THE BODY IN WHITE RATS UNDER THE EXPOSURE TO SODIUM FLUORIDE

We calculated studied the state of the hormonal status in experimental animals under the influence of sodium fluoride in 45 adult rats (males and females) of the Wistar population, which were orally administered a solution of sodium fluoride at a rate of 20 mg / kg of weight daily in the morning on an empty stomach, under the model conditions of intoxication. The duration of the subacute experiment was 1.5 months, after which the animals were euthanized by decapitation. Comprehensive assessment of the hormonal status in white rats was carried out by radioisotope methods in the serum. The results showed reduced levels of folliculotropin and progesterone, increased levels of thyroxine, adrenocorticotropin, glucagon, triiodothyronine, thyrotropin and calcitonin, while insulin, somatostatin and serum glucose levels decreased. There was no change in the dynamics of the content of sex hormones - luteotropin, prolactin, testosterone compared with the control (P&gt; 0.05). Furthermore, in the blood serum of rats, there was an increase in the levels of prostaglandin PGE2, prostacyclin (6 keto-PGF1a), leukotriene B4 and a decrease in the concentrations of prostaglandins PGE1, PGF2a and leukotriene C4. At all levels of the study of the endocrine system, deep shifts in the functional activity of the hypothalamus-pituitary-cortical substance of the adrenal glands, thyroid gland, and sympatho-adrenal structures have been identified. Analysis of the detected changes in the hormonal status allows judging the nonspecific reaction of the body to fluoride intoxication and reflects the state of the protective-adaptive mechanisms, in which the hypothalamus, the thyroid gland and the adrenal glands play a large role. Changes in the dynamics of concentrations of hormones and histohormones reflected a significant stress of the protective-adaptive mechanisms, which, in terms of structural and functional units, led to disruption of metabolic processes, including those associated with the development of fluoride intoxication. Disruption of the balance of hormones and functioning of the endocrine organs and systems entails profound changes in the metabolic processes and the immunobiological reactivity of the organism, weakening the action of the protective-adaptive mechanisms in maintaining the homeostatic function.

Fluoride removal from water by electrocoagulation: Effect of the type of water and the experimental parameters

Contamination of the ground water with fluoride is a great problem worldwide. Removal of fluoride (F−) ions from simulated natural waters containing fluoride by electrocoagulation (EC) using aluminum electrodes, has been investigated in a discontinuous lab cell. Two types of water have been studied: local tap water and deionized water-based luoride solutions of sodium fluoride with addition of sodium chloride to reach the desired conductivity. The effect of four operating parameters has been followed for a current density fixed at 5 mA/cm2 within the following ranges: fluoride concentration (5–50 mg/L), temperature (25–55 °C), conductivity (1–6 mS/cm) and initial pH (4–8.5). In accordance with published data, the presence of 61 mg/L buffering hydrogencarbonate ions in the tap water was found to substantially reduce the Al(III) amount required for a given abatement in comparison with deionized water. Performance comparison of the discontinuous electrocoagulation treatment between the two types of water has been discussed for 90% abatement of F− introduced, in terms of the amount of Al(III) dissolved over the initial fluoride concentration, the parameters of a previous adsorption model and the fraction of Al(III) flocs not involved in the adsorption. EC performances were shown to be governed by the solution pH for the two types of water, with little effect of the other operating conditions: at initial pH 6, F− abatement was found to require two or three times less trivalent aluminium than at initial pH 8.5.

Characterization of a trans–trans Carbonic Acid–Fluoride Complex by Infrared Action Spectroscopy in Helium Nanodroplets

The high Lewis basicity and small ionic radius of fluoride promote the formation of strong ionic hydrogen bonds in the complexation of fluoride with protic molecules. Herein, we report that carbonic acid, a thermodynamically disfavored species that is challenging to investigate experimentally, forms a complex with fluoride in the gas phase. Intriguingly, this complex is highly stable and is observed in abundance upon nanoelectrospray ionization of an aqueous sodium fluoride solution in the presence of gas-phase carbon dioxide. We characterize the structure and properties of the carbonic acid–fluoride complex, F–(H2CO3), and its deuterated isotopologue, F–(D2CO3), by helium nanodroplet infrared action spectroscopy in the photon energy range of 390–2800 cm–1. The complex adopts a C2v symmetry structure with the carbonic acid in a planar trans–trans conformation and both OH groups forming ionic hydrogen bonds with the fluoride. Substantial vibrational anharmonic effects are observed in the infrared spectra, most notably a strong blue shift of the symmetric hydrogen stretching fundamental relative to predictions from the harmonic approximation or vibrational second-order perturbation theory. Ab initio thermostated ring-polymer molecular dynamics simulations indicate that this blue shift originates from strong coupling between the hydrogen stretching and bending vibrations, resulting in an effective weakening of the OH···F– ionic hydrogen bonds.