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The dose–response relationship, or exposure–response relationship, describes the magnitude of the response of an organism, as a function of exposure (or doses) to a stimulus or stressor (usually a chemical) after a certain exposure time. [1] Dose–response relationships can be described by dose–response curves. This is explained further ...
Toxciant concentration is on the X-axis and biological response is on the Y-axis. Point estimation is a technique to predict population parameters based on available sample data and can be used to relate the mass based concentration to a toxicity based metric. Point estimates in toxicology are frequently response endpoints on a dose response curve.
For instance, if we assign dose concentration the symbol C, and time the classic t, then for any two dose schema, if C 1 t 1 =C 2 t 2, then under Haber's rule the two dose schema are equivalent. Haber's rule is an approximation, useful with certain inhaled poisons under certain conditions, and Haber himself acknowledged that it was not always ...
The threshold dose-response model is widely viewed as the most dominant model in toxicology. [6] An alternative type of model in toxicology is the linear no-threshold model (LNT), while hormesis correspond to the existence of opposite effects at low vs. high dose, which usually gives a U- or inverted U-shaped dose response curve.
Toxicokinetic profiles can change with increasing exposure duration or dose. Real world environmental exposures generally occur as low level mixtures, such as from air, water, food, or tobacco products. Mixture effects may differ from individual chemical toxicokinetic profiles because of chemical interactions, synergistic, or competitive processes.
Threshold dose is a dose of drug barely adequate to produce a biological effect in an animal. In dose-response assessment, the term ‘threshold dose’ is refined into several terminologies, such as NOEL, NOAEL, and LOAEL. They define the limits of doses resulting in biological responses or toxic effects. [3]
A toxicologist working in a lab (United States, 2008)Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms [1] and the practice of diagnosing and treating exposures to toxins and toxicants.
In toxicology, the median lethal dose, LD 50 (abbreviation for "lethal dose, 50%"), LC 50 (lethal concentration, 50%) or LCt 50 is a toxic unit that measures the lethal dose of a given substance. [1] The value of LD 50 for a substance is the dose required to kill half the members of a tested population after a specified test duration.