Abstract
The present study examined the adverse effects of fluoride exposure on embryos and larvae of Rana chensinensis. Survival, morphological abnormalities, growth and development, time to metamorphosis and size at metamorphic climax of R. chensinensis were examined. Our results showed that embryos malformation occurred in all fluoride treatments. Morphological abnormalities of embryos are characterized by axial flexures, the extrusion of fin axis, edema, and ruffled dorsal and ventral fin. Additionally, 4.1mg F–/L and above could significantly inhibit embryos growth and development. On day 15, total length and weight of tadpole were significantly lower in 19.6 and 42.4mg F–/L treatments compared to control. However, significant reductions in total length and weight were observed only at 42.4mg F–/L on day 30. Moreover, significant metamorphic delay and decrease in the size at metamorphic climax were found in larvae exposed to 42.4mg F–/L. Taken together, embryos of R. chensinensis are more vulnerable to fluoride exposure than their tadpoles. Our results suggested that the presence of high concentrations fluoride might increase mortality risk and a reduction in juvenile recruitment in the field by increasing embryos malformation, delaying metamorphosis and decreasing size at metamorphosis.
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Necessity to Pay Attention to the Effects of Low Fluoride on Human Health: an Overview of Skeletal and Non-skeletal Damages in Epidemiologic Investigations and Laboratory Studies.
Due to the implementation of water improvement and fluoride reduction plans supported by central and local governments in recent years, areas with high fluoride exposure are being gradually decreased. Therefore, it is of practical importance to study the effect of low fluoride on human health. Epidemiologic investigations and in vivo
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Impact of subchronic exposure to triclosan and/or fluoride on estrogenic activity in immature female rats: The expression pattern of calbindin-D9k and estrogen receptor a genes.
This study explored the influence of triclosan (TCS) in the absence and presence of sodium fluoride (NaF) on estrogenic activity and thyroid function of adolescent female rats. The results indicated that the individual exposure to TCS evoked a significant decline in T3 and T4 but the levels of estradiol, FSH,
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Effect of sodium fluoride on the structure and function of the thyroid and ovary in albino rats (Rattus Norvegicus).
Objective: The objective was to investigate the effect of sodium fluoride (NaF) on the structure and function of the thyroid and ovary in albino rats. Method: Twenty-four female adult albino rats, 160–180 g body weight (bw), were divided into four groups of 6: the control group (I) received defluoridated water while the other
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Fluoride in Drinking Water: A Scientific Review of EPA’s Standards.
Excerpts: Summary Under the Safe Drinking Water Act, the U.S. Environmental Protection Agency (EPA) is required to establish exposure standards for contaminants in public drinking-water systems that might cause any adverse effects on human health. These standards include the maximum contaminant level goal (MCLG), the maximum contaminant level (MCL), and the secondary
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Effect of fluoride on endocrine tissues and their secretory functions - review.
Highlights Fluoride induce e.g. oxidative stress, apoptosis and inflammation in endocrine tissues. Fluoride causes changes in the level of hormones released from endocrine tissues. Fluoride causes changes in the morphology of endocrine tissues. Abstract The effects of fluoride on endocrine tissues has not been sufficiently explored to date. The current body of
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Fluoride, Water Hardness, and Endemic Goitre
Variations in goitre prevalence were found to correlate closely with the fluoride content (p=0-74; P<0-01) and with the hardness (p=0.77; P<0-01) of the water in each village. The effects of fluoride and water hardness seem to be independent.
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Is fluoride-induced hyperthyroidism a cause of psychosis among East African immigrants to Scandinavia?
When people with a compensated fluoride-induced hypothyroidism move to a low-fluoride area, the fluoride-induced inhibition of the production of thyroid hormones ceases. In Scandinavia, the dietary intake of iodine is usually quite high due to iodized table salt and easy access to marine fish. Under these conditions, the elevated capacity for production of thyroid hormones may result in hyperthyroidism.
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Fluoride's Effect on Male Reproductive System: Animal Studies
Over 60 studies on animals (including rats, mice, roosters, and rabbits) have found that fluoride adversely impacts the male reproductive system. These studies have repeatedly found the following effects: (1) decreases in testosterone levels; (2) reduced sperm motility; (3) altered sperm morphology; (4) reduced sperm quantity; (5) increased oxidative stress; (6) and reduced capacity to breed.
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Fluoride's Effect on the Male Reproductive System -- In Vitro Studies
Carefully controlled in vitro studies have found that direct exposure of fluoride to the testes or semen inhibits testosterone production and damages sperm. While researchers have known since the 1930s that mega concentrations of fluoride can completely (but reversibly) immobilize sperm, it was not until the 1970s and 1980s that researchers found that relatively modest concentrations of fluoride could cause damage prior to complete immobilization.
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Fluoride Exposure Aggravates the Impact of Iodine Deficiency
A consistent body of animal and human research shows that fluoride exposure worsens the impact of an iodine deficiency. Iodine is the basic building block of the T3 and T4 hormones and thus an adequate iodine intake is essential for the proper functioning of the thyroid gland. When iodine intake is inadequate during infancy and
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