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PubMed1990

[Fluoride level in human nails and its significance].

Bone tissue investigation provides the best indicator for fluorine saturation of the organism. However, the intravital bone biopsy--as an invasive method, is not applicable in prophylactic studies. Thus, attention was focussed on the nails that constitute an easily accessible material being able to reflect the chronic accumulation of fluorine in the organism. In the actual paper it has been endeavoured to find out the routes, on which fluorine is deposited in the nails, if there is any dependence between the fluorine content in the nails and the age of the studied subjects, and whether the concentration of fluoride in the nails depends on the fluctuation of this element in the environment, and which of the parameters exert influence upon it. The performed investigations permitted the following conclusions to be drawn: 1. The nails furnish a readily accessible material for studying fluorine saturation in the organism. 2. Fluorine may be accumulated in the nails on internal pathway through circulatory system, and from outside--by means of direct absorption. 3. Since relatively high content of fluoride has been revealed in the nails of the youngest children, they should be protected against further supply of fluorine compounds from outside. 4. In the areas not polluted by fluorine compounds there is a lack of statistically significant dependence between the content of fluoride in the nails and the age.

Adolescent↗
PubMed1994

Content of fluorine in vegetables and fruits from an industrial area.

Content of fluorine in vegetables and fruits from allotments situated in an industrial area as well as in an agricultural area without industrial emissions was determined. The fluorine determination was made by means of a potentiometric method with application of an ion-selective electrode. Statistically significant differences between the fluorine content in vegetables and fruits from an area contaminated with the emissions of fluorine compounds and the fluorine content in vegetables and fruits from the control area were found. Significant differences between the fluorine content in above- and under-ground parts of some vegetables were stated. The greatest fluorine content appeared in parsley haulm and in black currants.

Fluorine↗
PubMed1999

Electrolytic Partial Fluorination of Organic Compounds. 31.(1) Regioselective Anodic Fluorination of 2-Quinolyl and 4-(7-Trifluoromethyl)quinolyl Sulfides and the Factors Affecting Its Optimization.

Electrochemical fluorination of 2-quinolyl and 4-(7-trifluoromethyl)quinolyl sulfides bearing an electron-withdrawing group at the position alpha to the sulfur atom was studied. Fluorination was successfully carried out using Et(4)NF.nHF (n = 3, 4) and Et(3)N.3HF as a supporting electrolyte and a fluoride ion source in dimethoxyethane in a divided cell to provide the corresponding alpha-fluorinated sulfides in good yields. A trifluoromethyl group positioned on the quinoline ring significantly enhanced anodic alpha-fluorination. 4-(Methylthio)-7-(trifluoromethyl)quinoline was also found to undergo anodic fluorination efficiently. Solvent effects of various donor numbers were also established.

Journal Article↗
PubMed2005

Isolation and properties of a pure bacterial strain capable of fluorobenzene degradation as sole carbon and energy source.

A pure bacterial strain capable of aerobic biodegradation of fluorobenzene (FB) as the sole carbon and energy source was isolated by selective enrichment from sediments collected from a polluted site. 16S rRNA and fatty acid analyses support that strain F11 belongs to a novel genus within the alpha-2 subgroup of the Proteobacteria, possibly within a new clade related to the order Rhizobiales. In batch cultures, growth of strain F11 on FB led to stoichiometric release of fluoride ion. Maximum experimental growth rate of 0.04 h-1 was obtained at FB concentration of 0.4 mM. Growth kinetics were described by the Luong model. An inhibitory effect with increasing FB concentrations was observed, with no growth occurring at concentrations higher than 3.9 mM. Strain F11 was shown to be able to use a range of other organic compounds, including other fluorinated compounds such as 2-fluorobenzoate, 4-fluorobenzoate and 4-fluorophenol. To our knowledge, this is the first time biodegradation of FB, as the sole carbon and energy source, by a pure bacterium has been reported.

Aerobiosis↗
PubMed2005

Biological evaluation of 2-aryl-2-fluoropropionic acids as possible platforms for new medicinal agents.

We investigated the cyclooxygenase (COX) inhibitory and anticancer activities of 2-aryl-2-fluoropropionic acids 1a-e. These fluorinated compounds showed lower inhibitory activity toward COX-1 than the corresponding non-fluorinated compounds 2a-e with retained inhibitory activity against COX-2 resulting in modification of the balance of COX-1/COX-2 inhibitions, and they showed little anticancer activity. Interesting differences of the activities between (S)- and (R)-enantiomers were observed in some cases.

Antineoplastic Agents↗
PubMed2004

[Fluorine as a factor in premature aging].

The use of fluorine compounds in various areas of medicine, particularly in dentistry, as well as in agriculture and industry became very popular in the second half of the 20th century. Fluorine owed this widespread acceptance to observations that its compounds stimulate ossification processes and reduce the prevalence of caries. Unfortunately, growing expectations overshadowed the truth regarding interactions of fluoride on the molecular level. The fact was often ignored that fluoride is toxic, even though laboratory data stood for a careful approach to the benefits of usage. Excessive exposure to fluoride may lead to acute poisoning, hyperemia, cerebral edema, and degeneration of the liver and kidneys. Acute intoxication through the airways produces coughing, choking, and chills, followed by fever and pulmonary edema. Concentrated solutions of fluorine compounds produce difficult to heal necrotic lesions. In spite of these dramatic symptoms, acute intoxications are relatively rare; the more common finding is chronic intoxication attributable to the universal presence of fluorine compounds in the environment. The first noticeable signs of excessive exposure to fluoride in contaminated water, air, and food products include discolorations of the enamel. Dental fluorosis during tooth growth and loss of dentition in adulthood are two consequences of chronic intoxication with fluorine compounds. Abnormalities in mineralization processes affect by and large the osteoarticular system and are associated with changes in the density and structure of the bone presenting as irregular mineralization of the osteoid. Fluorine compounds also act on the organic part of supporting tissues, including collagen and other proteins, and on cells of the connective tissue. These interactions reduce the content of collagen proteins, modify the structure and regularity of collagen fibers, and induce mineralization of collagen. Interactions with cells produce transient activation of osteoblasts, stimulate fibroblasts to produce collagenase, and trigger toxic reactions in osteocytes and chondrocytes of trabecular bone. Growing deformations of the skeleton reduce mobility and result in permanent crippling of the patient. Fluoride increases the mass of non-collagen proteins such as proteoglycans and glucosaminoglycans, accelerating skin aging even though protein biosynthesis is generally suppressed. The final outcome includes progressive vascular lesions and disorders of energy metabolism in muscles. In conclusions, the use of fluoride, particularly by dentists and pediatricians, must be controlled and adapted to individual needs. It is worth remembering that fluoride: is the cause of disability due to bone deformations and abnormalities in the musculoskeletal system; reduces the incidence of caries but do not protect against tooth loss; exerts an adverse effect of metabolic processes in the skin; accelerates calcification of vessels and thus reduces their elasticity; inhibits bioenergetic reactions, in particular oxidative phosphorylation, reducing physical activity of muscles. These findings suggest that fluorine may be yet another factor in accelerated aging and revive the dispute started more than two and half thousand years ago whether aging is a physiologic or pathologic process. The understanding of factors modifying the process of aging is the basis for preventive measures aimed at extending life and maintaining full psychosocial activity.

Aging↗
PubMedDate not supplied

In vivo fluorine-19 MR imaging: relaxation enhancement with Gd-DTPA.

The lack of a naturally occurring background signal from fluorine in magnetic resonance (MR) imaging makes fluorinated compounds potentially attractive candidates for tissue-specific MR contrast agents. Problems associated with the in vivo use of fluorinated compounds are toxicity, which limits the amount of agent that can be used; multiple resonance lines; and an excessively long T1, which leads to long sequence TRs and consequently long imaging times. Many fluorinated agents also possess complex MR spectra that result in chemical shift artifacts if not corrected. The authors demonstrate the use of an extracellular fluorinated agent with a single MR peak for selective imaging of a brain abscess in an animal model and show that the image signal per unit of acquisition time can be enhanced through the use of a T1 relaxation agent, gadolinium diethylenetriamine-pentaacetic acid (DTPA). Trifluoromethylsulfonate was administered at a fluorine-19 dose of 4 mmol/kg, and fluorine images of the induced abscess were acquired before and after the injection of a standard dose of Gd-DTPA (0.1 mmol/kg); non-section-selected projection images were used. Typical imaging times were less than 5 minutes. The signal enhancement factor achieved was approximately four (4.0 +/- 0.8) with use of a 500/12 (TR msec/TE msec) spin-echo sequence.

Animals↗
PubMed2004

Heterometallic Ln/Hg compounds with fluorinated thiolate ligands.

The early lanthanide benzenefluorothiolates (Ln(SC(6)F(5))(3); Ln = La, Ce, Pr, Nd, Sm, Gd) react with Hg(SC(6)F(5))(2) in DME to form ionic heterometallic compounds with Ln cations and Hg anions. X-ray diffraction analyses of all compounds reveal an isostructural series with the general formula [(DME)(3)Ln(SC(6)F(5))(2)](2)[Hg(2)(SC(6)F(5))(6)]. In the structures, a fluorothiolate ligand has been extracted from the Ln coordination sphere that is saturated with three neutral DME donor ligands and a dative interaction between one ortho fluorine and the Ln. Distances between Ln and F do not vary simply with Ln ionic radius. There are two Ln cations with charge balanced by a Hg(2)(SC(6)F(5))(6) dianion composed of two distinctly nonideal Hg(II) tetrahedra, all connected through a series of pi-pi interactions that link cations with anions in a one-dimensional array and anions to anions in a more complex 2D network.

Crystallography, X-Ray↗
PubMed2002

Imaging of fluorine and boron from fluorinated boronophenylalanine in the same cell at organelle resolution by correlative ion microscopy and confocal laser scanning microscopy.

PURPOSE: There is a clear need for a technique that provides subcellular locations of fluorine and boron atoms from fluorinated neutron capture agents because positron emission tomography is being tested as a tool for providing tumor boron concentrations in boron neutron capture therapy. EXPERIMENTAL DESIGN: Ion microscopy was used in combination with confocal laser scanning microscopy to investigate the subcellular locations of fluorine and boron from fluorinated p-boronophenylalanine (F-BPA) in human glioblastoma T98G cells. The fluorinated compound was also compared with p-boronophenylalanine (BPA) for delivery of boron after a clinically relevant 6-h exposure. Mitochondria were identified by rhodamine 123 labeling. A strict cryogenic sample preparation was used, and measurements were made in fractured freeze-dried cells. RESULTS: The nucleus, a perinuclear mitochondria-rich cytoplasmic region, and the remaining cytoplasm were the three subcellular regions identified in individual T98G cells. In cells treated with F-BPA, the mitochondria-rich perinuclear cytoplasmic region exhibited significantly lower fluorine and boron signals than the remaining cytoplasm and the nuclei. Ion microscopy observations revealed a nearly 1:1 distribution of fluorine and boron in subcellular compartments. Quantitative subcellular observations indicated that there was no significant difference in boron delivery to subcellular compartments between the F-BPA and nonfluorinated BPA. CONCLUSIONS: These observations provide the first direct evidence that fluorine and boron from fluorinated BPA are cocompartmentalized in cells and that the fluorinated compound is as efficient for boron delivery as the nonfluorinated BPA at a clinically relevant time point. These observations provide strong support for the use of F-BPA in positron emission tomography biodistribution studies for boron neutron capture therapy.

Boron↗
PubMed2004

[Seasonal fluctuations in fluoride content in waters of the Warta oxbow lake in Luboń].

Studies were carried out in 2002-2003 at the Department of Inland Fishing and Aquaculture, Agricultural University of Poznań, on seasonal fluctuations in fluoride content in waters of the Warta oxbow lake in Luboń (52 degrees 19' N, 16 degrees 53' E). This reservoir has been loaded during several decades with fluorine compounds, originating from the deposits of post-crystallization lye of aluminum fluoride and fluorosilicic acid. The greatest amounts of fluorine compounds were deposited in the bottom sediments in the deepest part of the reservoir. On the basis of these two-year observations it was concluded that the concentration of fluoride in water is subject to significant variations (between 1.0 and 6.2 mg F(-)/L). The lowest fluoride concentration in water was recorded during vernal circulation. On the other hand, the highest values were found in the bottom water layer during the summer stagnation. Seasonal fluctuations in fluoride content in waters of the Warta oxbow lake were closely connected with mineralization in the bottom sediment as revealed by oxygen deficiencies in the bottom water layer.

Fluorides↗
PubMed1984

Inhibitory activity and resistance to hydrolysis by beta-lactamases of some (D,L)-7-(alpha-fluoroacylamino)cephalosporins.

The synthesis of a series of (D,L)-7-(alpha-fluoroacylamino)-cephalosporanic acids are described. In vitro antimicrobial activity was determined in comparison with the corresponding non-fluorinated compounds. None of them were found to be better than clinically used cephalosporins. Resistance to and inhibition of beta-lactamases from gram-negative organisms were also determined. All the fluorinated derivatives were found to be as resistant to hydrolysis by Escherichia coli R+TEM beta-lactamase as the corresponding non-fluorinated compounds, but resulted more resistant (from 2.3 to 61.2 times) to Enterobacter cloacae 214 beta-lactamase. Title compounds were also found to be better inhibitors of E. cloacae 53 and E. cloacae 214 beta-lactamases than the related non-fluorinated cephalosporins.

Bacteria↗