Abstract
Maize seedlings of the genotype C I Sh Wx were fumigated with hydrogen fluoride gas (HF) continuously for 4, 6, 8 and 10 days. Miscrospore mitosis of the treated plants indicated the presence of fragments and bridges suggesting the occurrence of the phenomenon of breakage-fusion-bridge cycle of McClintock. This phenomenon was later confirmed by the production of endosperm mosaicisms. The period of fumigation was clearly related to the extent of the area resulting from the B-F-B cycle. Recombination values were estimated from F2 data for the regions C-sh and sh-wx. There was a significant increase in the frequency of crossing over for region I with maximum increase being for the 4 days duration. The recombination value for region II showed no significant deviation from the control. These findings indicate that HF in addition to being a mutagenic agent is also able to reduce crossing over in certain chromosome segments.
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Sodium fluoride is a less efficient human cell mutagen at low concentrations
Sodium fluoride was found to induce gene-locus mutations at the thymidine kinase (tk) and hypoxanthine guanine phosphoribosyl transferase (hgprt) loci in human lymphoblastoid cells. A single, 28 hr exposure to up to 600 micrograms/ml sodium fluoride induced a concentration-dependent increase in mutant fraction at both gene loci and reduced cell
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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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The effects of sodium fluoride and iodacetamide on mutation induction by x-irradiation in mature spermatoza of drosophila
The effect of two inhibitors of glycolysis, NaF and iodacetamide on the production of recessive lethal mutations by X-rays in mature Drosophila sperm has been investigated. Pre-treatment with NaF resulted in a consistent and highly significant increase of the mutation frequency. This effect is thought to result from interference with
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In vivo suppression by fluoride of chromosome aberrations induced by mitomycin-C in mouse bone marrow cells.
In vivo clastogenic effects of mitomycin-C (MMC) in bone marrow cells of four groups of young male Swiss albino mice exposed to 0, 7.5, 15, and 30 mg NaF/L in their drinking water for 30 days were investigated. The percentages of aberrant metaphases and chromosome aberrations in all F-treated mice
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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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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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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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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: The "Oral Health Research Institute's" Studies
Although many in vitro and in vivo studies have detected mutagenic effects from fluoride exposure, the Oral Health Research Institute at Indiana University's School of Dentistry has repeatedly failed to find any such effect in multiple studies on the subject.
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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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