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PubMed1989

Studies on the toxicology of fluorine compounds. I. Histological and histochemical investigations on the liver, heart, lungs, and stomach of rats exposed to hydrogen fluoride.

The liver, heart, lungs, and stomach of rats exposed to hydrogen fluoride were studied. Histological examination showed partial liver necrosis and emphysema. Using histochemical methods the effect of fluorine ions was found in: a reduction of the activity of succinic and beta-hydroxybutyric dehydrogenases in the liver, heart muscle, superficial and glandular epithelium cells, and in lamina propria of the gastric mucosa; an increase in the activity of lactate dehydrogenase in liver cells; an increase in the activity of acid phosphatase in the liver, heart muscle, bronchus epithelium, bronchioli, and interalveolar septum cells; an increase in the activity of alkaline phosphatase in the liver, lungs, and heart muscle connective tissue, and in all gastric epithelium cells. The results obtained mainly point to the inhibition of oxidative metabolism by fluoride ions.

Animals↗
PubMed1993

Use of Fluorinated Compounds To Detect Aromatic Metabolites from m-Cresol in a Methanogenic Consortium: Evidence for a Demethylation Reaction.

Anaerobic sewage sludge was used to enrich a methanogenic m-cresol-degrading consortium. 6-Fluoro-3-methylphenol was synthesized and added to subcultures of the consortium with m-cresol. This caused the accumulation of 4-hydroxy-2-methylbenzoic acid. In a separate experiment, the addition of 3-fluorobenzoic acid caused the transient accumulation of 4-hydroxybenzoic acid. Inhibition with bromoethanesulfonic acid caused the accumulation of benzoic acid. Thus, the proposed degradation pathway was m-cresol --> 4-hydroxy-2-methylbenzoic acid --> 4-hydroxybenzoic acid --> benzoic acid. The m-cresol-degrading consortium was able to convert exogenous 4-hydroxybenzoic acid and benzoic acid to methane. In addition, for each metabolite of m-cresol identified, the corresponding fluorinated metabolite was detected, giving the following sequence: 6-fluoro-3-methylphenol --> 5-fluoro-4-hydroxy-2-methylbenzoic acid --> 3-fluoro-4-hydroxybenzoic acid --> 3-fluorobenzoic acid. The second step in each of these pathways is a novel demethylation which was rate limiting. This demethylation reaction would likely facilitate the transformation of the methyl group to methane, which is consistent with the results of a previous study that showed that the methyl carbon of m-[methyl-C]cresol was recovered predominantly as [C]methane (D. J. Roberts, P. M. Fedorak, and S. E. Hrudey, Can. J. Microbiol. 33:335-338, 1987). The final aromatic compound in the proposed route for m-cresol metabolism was benzoic acid, and its detection in these cultures merges the pathway for the methanogenic degradation of m-cresol with those for the anaerobic metabolism of many phenols.

Journal Article↗
PubMed1994

Microemulsions of perfluorinated and semi-fluorinated compounds.

Perfluorocarbons combine high gas dissolving capacities with extreme chemical and biological inertness: they are good oxygen carriers in artificial blood and in liquid breathing. However fluorocarbons are highly hydrophobic molecules. To solve the problem of their transport, it is necessary to use the perfluorocarbons as an oil-in water emulsion (O/W). To avoid harsh treatment to form such emulsions and in order to have injectable "blood substitutes", microemulsions seem particularly attractive since they are fluid, transparent, thermodynamically stable microheterogeneous systems. Microemulsions, contrarily to classical emulsions, are formed spontaneously by adding suitable surfactants (or a surfactant+a cosurfactant) in appropriate proportions to a non miscible mixture of water and oil. Biocompatible O/W microemulsions are difficult to obtain because of: 1) the existing segregation between perfluorinated and hydrogenated chains, resulting, in some cases in heterogeneities or gelation phases; 2) the toxicity of some components; 3) the possible harmfulness of the dispersed system, etc... We'll discuss all the parameters involved of the microemulsification process, the nature of products, the phase diagrams, and the phase behaviors. This study will outline certain guidelines necessary for the formation of microemulsions of perfluorinated (or almost completely fluorinated) oils with perfluorinated (or partially fluorinated) surfactants.

Animals↗
PubMedDate not supplied

[Modifying effect of nutrition on the mutagenic activity of phosphorus and fluorine compounds].

The test animals were fed with low-grade food during 2-5 months under conditions of acute and chronic action of hydrogen phosphide and hydrogen fluoride induced by inhalation, that resulted in the pronounced impairment of the chromosomal apparatus of the bone marrow cells in the rats. A principal possibility has been established of modification of the hydrogen phosphide and hydrogen fluoride cytogenetic effect by the alimentary action. In particular, it has been found that the effect is significantly higher when the rats are fed with a low-grade ration than under conditions of balanced nutrition.

Animals↗
PubMedDate not supplied

Photonuclear activation ratios in fluorine compounds; an index of bremsstrahlung quality.

Samples of potassium hexafluorosilicate (K2SiF6) and polytetrafluoroethylene (C2F4)n were irradiated in the bremsstrahlung beam from a clinical linear electron accelerator at integral values of endpoint energy between 13 and 32 MeV. Sample positron activities produced by the reactions 39K(gamma, n) 38K, 19F(gamma, n) 18F, and 12C(gamma, n)11C, were determined by counting the gamma radiation. Saturation activities per target nucleus were calculated from these data. For the K2SiF6 samples, the photonuclear activation ratio (PAR) of the 7.6 min 39K saturation activity per nucleus divided by the 18F result increased by more than 20% per MeV between 15 and 21 MeV. For the (C2F4)n samples the ratio (PAR) of the 11C saturation activity per nucleus to that for 18F increased by more than 24% per MeV between 22 and 26 MeV. Quality changes caused by the lead flattening filter were easily detectable using the PAR technique. Because of the high sensitivity to bremsstrahlung spectrum changes these PAR values can serve as sensitive indices of quality for high-energy beams.

Fluorides↗