Hormesis has been defined as a dose-response relationship in which there is a stimulatory response at low doses but an inhibiting response at high doses, resulting in a Uor inverted U-shaped dose response. Until now, regulatory agencies have been reluctant to address this new insight or adjusted their routines for regulating such substances. Should regulators change their principles of decision...

Hormesis is a concept of biphasic dose–response to different toxicological and pharmacological stimuli. According to this concept, a noxious agent at a small dose can exert a beneficial action. Among the known hormetic agents are pro-oxidants, heavy metals, heat, radiation, exercise, food restriction and different kinds of stress. All these agents are present in the environment so that the horm...

Hormesis has been defined as a dose-response relationship in which there is a stimulatory response at low doses but an inhibiting response at high doses, resulting in a U- or inverted U-shaped dose response. Until now, regulatory agencies have been reluctant to address this new insight or adjusted their routines for regulating such substances. Should regulators change their principles of decisi...

Concentration addition (CA) was proposed as a reasonable default approach for the ecological risk assessment of chemical mixtures. However, CA cannot predict the toxicity of mixture at some effect zones if not all components have definite effective concentrations at the given effect, such as some compounds induce hormesis. In this paper, we developed a new method for the toxicity prediction of ...

Low doses in the mGy range cause a dual effect on cellular DNA. One is a relatively low probability of DNA damage per energy deposition event and increases in proportion to the dose. At background exposures this damage to DNA is orders of magnitude lower than that from endogenous sources, such as reactive oxygen species. The other effect at comparable doses is adaptive protection against DNA da...

Several studies on the effect of inhaled plutonium-dioxide particulates and the incidence of lung tumors in dogs reveal beneficial effects when the cumulative alpha-radiation dose is low. There is a threshold at an exposure level of about 100 cGy for excess tumor incidence and reduced lifespan. The observations conform to the expectations of the radiation hormesis dose-response model and contra...

MTLn3 cells derived from mouse mammary epithelium are known to be highly malignant and are resistant to both radio- and chemo-therapy. We exposed MTLn3 cells to various doses of inorganic Arsenic trioxide (As2O3) in combination with ionizing radiation. Cells were treated with a series of As2O3 concentrations ranging from 20 μM to 1.22 nM for 8 hour, 24 hour and 48 hour periods. Post-treated cel...

A recent update on the atomic bomb survivor cancer mortality data has concluded that excess relative risk (ERR) for solid cancers increases linearly with dose and that zero dose is the best estimate for the threshold, apparently validating the present use of the linear no threshold (LNT) model for estimating the cancer risk from low dose radiation. A major flaw in the standard ERR formalism for...