Abstract
The clastogenic potential of sodium fluoride was determined both in vitro (using cultured human lymphocytes) and in vivo (using the rat bone-marrow micronucleus test). The incidence of chromosome aberrations in human lymphocyte cultures exposed to 20 or 40 micrograms/ml sodium fluoride (3 and 9% respectively) was significantly increased compared with control cultures (0.5%). However, the incidence of micronucleated polychromatic erythrocytes in male AP rats dosed 1000 mg/kg NaF (the maximum tolerated dose over 24 h) or 500 mg/kg NaF was similar to that in the animals dosed distilled water (vehicle control). Thus, sodium fluoride is clastogenic in vitro but not in vivo.
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Sodium fluoride-induced morphological and neoplastic transformation, chromosome aberrations, sister chromatid exchanges, and unscheduled DNA synthesis in cultured syrian hamster embryo cells
The effects of exposure of early-passage Syrian hamster embryo cells in culture to sodium fluoride have been studied with respect to induction of morphological and neoplastic transformation, chromosome aberrations, sister chromatid exchanges, and unscheduled DNA synthesis. Exposure of Syrian hamster embryo cells to NaF concentrations between 75 and 125 micrograms/ml
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Genotoxic evaluation of chronic fluoride exposure: micronucleus and sperm morphology studies
The purpose of this study was to investigate the genotoxic effects of chronic fluoride exposure on mammalian cells in vivo by use of the mouse bone-marrow micronucleus test and the sperm morphology methodology. Mice of genotype B6C3F1 were obtained at weaning and maintained on a low-fluoride diet (less than 0.2
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Sister chromatid exchange frequency and chromosome aberrations in residents of fluoride endemic regions of South Gujarat
Peripheral blood lymphocytes of residents of three villages and one nearby township in South Gujarat with fluoride concentrations in the drinking water of 1.56 - 3.46 and 0.6 - 0.8 ppm, respectively, were examined for their frequency of sister chromatid exchanges (SCE) and chromosome aberra-tions. The rates of SCEs and
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DNA damage induced by fluoride in rat kidney cells.
DNA damage by fluoride to newborn rat kidney cells isolated by enzymic digestion is reported. The cells were exposed for 24 hr to sodium fluoride at NaF concentrations of 0, 0.2, 0.4, 0.8, and 1.0 mM. Damage to DNA was determined by single cell gel electrophoresis assay (Comet assay). Significant breakage of DNA strands
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Chromosomal changes in maize induced by hydrogen fluoride gas
Maize seedlings of the genotype A1A2C1Wx were fumigated in growth chambers with hydrogen fluoride (HF) at a concentration of about 3 ug/m3. The experiment was run for 1O days, with the first group of treated plants removed from the chambers after 4 days and then at intervals of 2 days.
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Fluoride/Osteosarcoma Link Is Biologically Plausible
The "biological plausiblility" of a fluoride-osteosarcoma link is widely acknowledged in the scientific literature. The biological plausibility centers around three facts: 1) Bone is the principal site of fluoride accumulation, particularly during the growth spurts of childhood; 2) Fluoride is a mutagen when present at sufficient concentrations, and 3) Fluoride can stimulate the proliferation of osteoblasts (bone-forming cells).
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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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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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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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