Abstract
The L5178Y mouse lymphoma cell forward-mutation assay was used to test for the mutagenic activity of sodium and potassium fluoride at the thymidine kinase locus. Mutants were detected by colony formation in soft agar in the presence of trifluorothymidine. Mutagenic and toxic responses were observed in the concentration range of 300-600 micrograms/ml with both sodium and potassium fluoride. Approximately 3-fold increases in mutant frequency were observed for concentrations in the 500-700 micrograms/ml range that reduced the relative total growth to approximately 10% in the absence or presence of a rat-liver S9 activation system. A sample of 30% sodium fluoride-70% sodium bifluoride (NaHF2) induced a similar mutagenic response but was more toxic with respect to the fluoride concentration. A specificity for fluoride ions in causing mutagenesis was indicated by the fast that much higher concentrations of sodium or potassium chloride were necessary to cause toxicity and increases in the mutant frequency. The possible involvement of chromosomal changes was signaled by the predominant increase in the small colony class of mutants.
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Leukocyte response in young mice chronically exposed to fluoride
A light and fluorescent microscopy study of sternal and femoral bone marrow, taken from young Swiss mice exposed for up to 280 days to elevated levels of NaF in drinking water, revealed morphologic abnormalities in cell structure and mitotic figure formation in immature leukocytes. Alterations in the content and distribution
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Sodium fluoride induced chromosome aberrations and sister chromatid exchange in cultured human lymphocytes
Experimental sodium fluoride (NaF) up 10 30 times the level recommended In drinking waler (1 ppm) was compared with an inorganic salt for its ability to induce chromosome aberrations and sister chromatid exchange (SCE) in cultured human lymphocytes. An increase in the frequencies of chromosome aberrations but not of SCE
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Genotoxic damage in oral epithelial cells induced by fluoride in drinking-water on students of Tula de Allende, Hidalgo, Mexico
Fluoride (F-) compounds are present on the earth’s surface, water, volcanoes and are also a product of petrochemical and cement industries. Little amounts of F- are required for the formation of bones and enamel, however, according to World Health Organization (WHO), ingestion of over 1.5 mg/L of F- may be
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Sodium fluoride-induced chromosome aberrations in different stages of the cell cycle: a proposed mechanism
In an attempt to clarify the controversy about sodium fluoride (NaF) clastogenicity, the induction of chromosome aberrations in Chinese hamster ovary cells (CHO) by NaF was investigated. Following a protocol used for screening chemicals for clastogenic activity, significant increases of aberrant cells were observed when cells were exposed to NaF
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Effect of sodium fluoride on tumor growth
Recently a report (1) from this laboratory indicated that NaBr in relatively low concentrations accelerated the growth of mouse and egg cultivated tumor tissue. This result occurred when the drug was introduced by way of the drinking water in mice, by injection over the embryonic membranes of eggs inoculated with
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Fluoride & Osteosarcoma: A Timeline
Several human epidemiological studies have found an association between fluoride in drinking water and the occurrence of osteosarcoma (bone cancer) in young males. These studies are consistent with the National Toxicology Program's (NTP) cancer bioassay which found that fluoride-treated male rats had an dose-dependent increase in osteosarcoma. Although a number of studies have failed to detect an association between fluoride and osteosarcoma, none of these studies have measured the risk of fluoride at specific windows in time, which based on recent results, is the critical question with respect to fluoride and osteosarcoma.
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Fluoride's Mutagenicity: In vivo Studies
Consistent with dozens of in vitro studies, a number of in vivo studies, in both humans and animals, have found evidence of fluoride-induced genetic damage. In particular, research on humans exposed to high levels of fluoride have found increased levels of "sister chromatid exchange" (SCE). As noted in one study: "In
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NTP Bioassay on Fluoride/Cancer (1990)
In 1977, the U.S. Congress requested that animal studies be conducted to determine if fluoride can cause cancer. The result of the Congressional request was an extensive animal study conducted in the 1980s by the National Toxicology Program (NTP) and published in 1990. The main finding of NTP's study was a dose-dependent increase in osteosarcoma (bone cancer) among the fluoride-treated male rats.
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A Critique of Gelberg's Study on Fluoride/Osteosarcoma in New York
The case-control study by Gelberg, published first as a PhD dissertation and then later in two peer-reviewed journals, may represent the most substantive study on fluoride/osteosarcoma previous to Bassin’s 2001 analysis. In assessing Gelberg’s data, we were at first struck by the existence of several notable errors in both the thesis and papers. While these errors do raise questions about the study, our primary concern with Gelberg’s work relates to the methods she used to analyze her data.
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Micronucleus and Sister Chromatid Exchange Frequency in Endemic Fluorosis
The rise of sister chromatid exchange (SCE) and micronucleus (MN) in the peripheral blood lymphocytes of the fluorine-intoxicated patients indicates that fluorine is a mutagenic agent which can cause DNA and chromosomal damage.
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