Abstract
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. Microsporocyte smears from the treated plants revealed chromosomal aberations that included asynaptic regions, translocations, inversions; and bridges plus fragments or fragments by themselves. It is believed that these abnormalities were due to the physiological effect of HF causing the chromosomes to become sticky and/or to the occurrence of chromatid breakage followed by reunion to form structural changes. These findings indicate that HF is a mutagenic agent.
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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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Cytogenetic effect of inorganic fluorine compounds on human and animal cells in vivo and in vitro
The object of this study was the mutagenic effect of hydrogen fluoride, cryolite and their mixtures on chromosomes of cells of animals subjected to the inhalation of these compounds and also the mutagenic effect of sodium fluoride on cells of human leucocyte cultures. An increase from 1.24 (in the control) to
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DNA damage induced by fluoride in rat osteoblasts
A study is reported of DNA damage by fluoride to primary calvarial osteoblasts of newborn rats isolated by enzymic digestion. Sodium fluoride at concentrations of 0, 0.5, 1, 2, and 3 mmol/L was administered to the isolated osteoblast cells for 24 hr, and damage to DNA was determined by single
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Lack of DNA damage induced by fluoride on mouse lymphoma and human fibroblast cells by single cell gel (comet) assay
Fluoride has widely been used in Dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury on genetic apparatus. Genotoxicity tests constitute an important part of cancer research for risk assessment of potential carcinogens. In
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Clastogenic activity of sodium fluoride in great ape cells
Conflicting evidence has been reported concerning the mutagenicity of sodium fluoride (NaF), especially clastogenicity at concentrations of more than 1 mM. NaF is known to induce chromosome aberrations at these concentrations in human cells, but not in most rodent cells. We considered that such species-specific difference in chromosomal sensitivity would
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Fluoride & Liver Cancers in NTP Bioassay
On October 28, 1988, Battelle Columbus Laboratories submitted its Final Report to the NTP concerning the results of the Mouse study. The principal finding of Battelle's report was that a dose-dependent increase of a rare liver cancer (hepatocholangiocarcinoma) had occurred in the fluoride-treated male and female mice.
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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 & 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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