We just don't know which particular asbestos fibers contributed to the threshold dose
; indeed, given individual variability, we don't know what the threshold dose
is for any individual.
There is no threshold dose
for deterministic effects.
Because of this limited sensitivity, a threshold dose
cannot be proven conclusively to exist (although one's existence could perhaps reasonably be predicted from a qualitative understanding of underlying mechanisms).
HVD modeling can also involve an assumption that a threshold dose
defined by dichotomizing a continuous apical response has a log-normal distribution.
The dose-response model states that radiation risk increases as dose increases and that there is no threshold dose
. Even a small dose has the potential to cause a biological effect.
Summary of pyrethroid type, threshold dose
, [ED.sub.30], percentage of total mixture dose mass, and the absolute dose for each chemical.
These authors claimed primacy of hormesis over threshold dose
responses in 2003 (Calabrese and Baldwin 2003b).
KEY WORDS: adaptive response, biphasic, dose response, hormesis, hormetic, linear dose response, risk assessment, threshold dose
(1999) found that there did not appear to be a threshold dose
for estradiol-induced sex reversal of turtle embryos, the lowest dose tested (40 pg/g, ppt) showing 14% sex reversal in the turtle embryos.
Instillation of six different ultrafine carbon particles indicates surface area threshold dose
for acute lung inflammation in mice.
The threshold dose
for significant reduction of cortical thickness was 25 mg/kg, but the threshold dose
for failure of plasticity was much lower and could be detected at 1 mg/kg, the lowest dose used.
From this study, the authors concluded that the threshold dose
of peanut protein needed to elicit a response in a group of individuals allergic to peanuts varies.
This study attempts to determine if there is a threshold dose
exposure to TCE above which the developing heart is more likely to be affected.
(2) therefore suggests the existence of a threshold dose
for the carcinogenicity of genistein, as observed in the uterotrophic assay (3).
According to Frederick vom Saal, a professor in the Division of Biological Sciences at the University of Missouri in Columbia, nonmonotonic curves challenge the EPA's standard assumption of linear or threshold dose
responses, which holds that toxic effects always lessen as the dose is reduced toward zero.