Abstract
In Drosophila melanogaster the frequency of adults with melanotic tumors increases both when .larvae from genetically normal and genetically melanotic tum0r strains are exposed to nutrient containing silver nitrate. Larval nutrient containing sodium fluoride also has this effect on genetically normal individuals. The present work was performed to test simultaneously the melanotic tumorigenic
capacity of sodium fluoride in two different genetic lines in which such tumors normally occur or do not occur with appreciable frJ1quency.
. . . .
In D. Melanogaster, when larvae are grown in nutrient containing different concentrations of NaF, the tu-soj strain, which normally has a relatively strong genetic predisposition for the formation of melanotic tumors, demonstrates a significantly higher rate of induced melanotic tumors in the adult stage than does the wild·type Oregon R strain, which normally has a relatively weak genetic predisposition in this respect.
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Is fluoride a mutagen?
Recent studies suggest that fluoride may be genotoxic. While the concentration of fluoride in artificially fluoridated water (1 mg Fl-1) is generally considered to be "safe", levels of fluoride present in a number of widely used dental health products, such as fluoride-containing toothpaste, appear to be potentially mutagenic. Since fluoride
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Analysis of chromosomal abnormalities at anaphase-telophase induced by sodium fluoride in vitro
Don Chinese-hamster cells were treated with 25, 50, or 75 micrograms/milliliter (microg/ml) of sodium-fluoride (7681494) to determine the chromosomal effects of fluoride exposure on these cells. Cultures were assayed at 12, 24, and 36 hours after initiation of treatment. Chromosomal aberrations were recorded for all the concentrations used. Maximum effect
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Ameliorative effects of N-acetylcysteine on fluoride-induced oxidative stress and DNA damage in male rats' testis
This study was to elucidate DNA damage in rats treated with sodium fluoride (NaF) by performing 8-Hydroxy-2-deoxyguanosine (8-OHdG) immunohistochemical staining assays on seminiferous tubules of rats' testis, and also to evaluate the protective effects of N-acetylcysteine (NAC) on spermatogenesis. Male Sprague Dawley (SD) rats were exposed to a single dose
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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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Mutagenic effect of hydrogen fluoride on animals
The mutagenic effect of hydrogen fluoride in concentration 1.0 mg/m-3 was studied in rats and mice. Prolonged inhalation of this compound increased the frequency of cells with chromosome abnormalities in the bone marrow of albino rats. The mutagenic effect was higher in older animals. No dominant-lethal effect was observed in
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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 vitro Studies
According to the National Toxicology Program, "the preponderance of evidence" from laboratory "in vitro" studies indicate that fluoride is a mutagenic compound. Many substances which are mutagens, are also carcinogens (i.e. they can cause cancer). As is typical for in vitro studies, the concentrations of fluoride that have generally been tested
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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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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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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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