A PBPK model parameterized with empirical conjugation and deconjugation rate constants and calibrated for free BPA is needed to relate the dose response for toxic effects found in rodents to humans.
For other outcomes, exposure to a single, high (toxic) dose may trigger an adverse response, as with chloracne after exposure to 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) from the Seveso accident in northern Italy (Caramaschi et al. 1981).
At toxic doses the adaptive response of the cell is initially triggered but becomes overridden by the excessive toxicity, such that it is beyond the homeostatic ability of the cell to counteract the insult.
Risk characterisation of human exposure to chemicals requires information on the intrinsic toxic (hazardous) properties of the chemical, dose response of effects for the critical endpoints and exposure of the population.
Shape Index ( = measured cell perimeter 2/4 Π2 R2, R is the radius of the calculated circumscribed circle) and Roundness ( = R2 Π/area) morphological parameters were found to be following dose response profiles upon toxic exposure to various extent.
That function is best described by the dose response of the toxic effect.
The Regulation also states that the nanocomponents that are incorporated in the food should be first studied for dose response and the toxic effect of such components.
These data should be interpreted with caution, given the nonlinear dose response of BPA and the potential toxic, or near toxic, levels of BPA.
Additionally, a bell-shaped dose response curve balancing neuroprotective and potentially toxic effects might explain the observed effect of the highest cell dose, as is commonly seen in pharmaceutical drug testing.
A primary goal in developing cell-based quantitative network simulations of toxic response is to evaluate the shape of the dose response curve over a broad range of exposures.
PCB congeners were considered enzyme inducers if a continuous linear or nonlinear dose response could be identified without otherwise overt toxic effects.
