Elucidating isoniazid resistance using molecular
In occupational health, standards and guidelines are often set in terms of exposure, or allowable limits on concentrations in specific situations, such as in air in the workplace.
These exposure limits are predicated upon assumptions or information on the relationships between exposure and dose; however, often information on internal dose is unavailable.
Toxicology is the study of poisons, or, more comprehensively, the identification and quantification of adverse outcomes associated with exposures to physical agents, chemical substances and other conditions.
As such, toxicology draws upon most of the basic biological sciences, medical disciplines, epidemiology and some areas of chemistry and physics for information, research designs and methods.
The concepts of target organ and critical effect have been developed to aid in the interpretation of toxicological data.
Depending upon dose, duration and route of exposure, as well as host factors such as age, many toxic agents can induce a number of effects within organs and organisms.
As part of prevention strategies, toxicology is invaluable, since it is the source of information on potential hazards in the absence of widespread human exposures.
Toxicological methods are also widely used by industry in product development, to provide information useful in the design of specific molecules or product formulations.
Topics are also selected for ease of cross-reference within the Encyclopaedia.In modern terminology, exposure refers to the concentrations or amount of a substance presented to individuals or populationsamounts found in specific volumes of air or water, or in masses of soil.Dose refers to the concentration or amount of a substance inside an exposed person or organism.Toxicology can be divided into standard disciplines, such as clinical, forensic, investigative and regulatory toxicology; toxicology can be considered by target organ system or process, such as immunotoxicology or genetic toxicology; toxicology can be presented in functional terms, such as research, testing and risk assessment.It is a challenge to propose a comprehensive presentation of toxicology in this Encyclopaedia.