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Dose–response relationships generally depend on the exposure time and exposure route (e.g., inhalation, dietary intake); quantifying the response after a different exposure time or for a different route leads to a different relationship and possibly different conclusions on the effects of the stressor under consideration.
The linear no-threshold model (LNT) is a dose-response model used in radiation protection to estimate stochastic health effects such as radiation-induced cancer, genetic mutations and teratogenic effects on the human body due to exposure to ionizing radiation. The model assumes a linear relationship between dose and health effects, even for ...
Hormesis is a biological phenomenon where a low dose of a potentially harmful stressor, such as a toxin or environmental factor, stimulates a beneficial adaptive response in an organism. In other words, small doses of stressors that would be damaging in larger amounts can actually enhance resilience, stimulate growth, or improve health at lower ...
Temporality: The effect has to occur after the cause (and if there is an expected delay between the cause and expected effect, then the effect must occur after that delay). Biological gradient (dose–response relationship): Greater exposure should generally lead to greater incidence of the effect. However, in some cases, the mere presence of ...
Pharmacodynamics places particular emphasis on dose–response relationships, that is, the relationships between drug concentration and effect. [1] One dominant example is drug-receptor interactions as modeled by
A very low dose of a chemical agent may trigger from an organism the opposite response to a very high dose.. Radiation hormesis proposes that radiation exposure comparable to and just above the natural background level of radiation is not harmful but beneficial, while accepting that much higher levels of radiation are hazardous.
The dose-response relationship for a given effect (e.g., diarrhea) is therefore the relationship between the dose and the likelihood of experiencing this effect. When the response is less than about 10%, it is observed that there is a strictly proportional relationship between dose and response:
PK/PD relationships can be described by simple equations such as linear model, Emax model or sigmoid Emax model. [5] However, if a delay is observed between the drug administration and the drug effect, a temporal dissociation needs to be taken into account and more complex models exist: [6] [7] Direct vs Indirect link PK/PD models