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ICCVAM Biennial Report 2014-2015

ICCVAM Biennial Report 2014-2015

Glossary of Key Terms

3Rs: the principles of replacement, reduction, or refinement of animal use for scientific research or product safety testing

Accuracy: the closeness of agreement between a test method result and an accepted reference value, or the test method's proportion of correct outcomes

Acellular pertussis vaccines: vaccines that contain Bordatella pertussis proteins rather than whole bacterial cells

Acute systemic toxicity: the immediate or near-immediate effect of a toxic substance after it is absorbed and distributed throughout the body. Different acute systemic toxicities are distinguished by the route of exposure: by ingestion (oral), through the skin (dermal), or by inhalation.

Adverse outcome pathway (AOP): a conceptual framework constructed from existing knowledge that relates exposure of a type of toxic substance to subsequent steps that result in illness or injury

Agonist: a substance that increases activity of the target (estrogen or androgen) receptor

Agrochemical: a chemical product used in agriculture

Algorithm: a set of steps that are followed in order to complete a computational process

Allergen: a substance that can cause an allergic reaction

Allergic contact dermatitis (ACD): an allergic reaction that results from repeated direct skin contact with a skin sensitizer. Clinical signs of ACD include redness, swelling, blistering, and itching.

Alternative methods: testing methods that replace, reduce, or refine animal use

Androgen: a class of hormones, produced largely by the testes, that serve as the primary male hormones

Androgen receptor (AR): a protein molecule to which an androgen or androgen-like substance can attach. This interaction produces a chemical signal or triggers a cellular response.

Antagonist: a substance that decreases activity of the target (estrogen or androgen) receptor

Anticoagulant rodenticides: chemicals that inhibit blood clotting that are sold for the purpose of killing rodents

Antimicrobial: capable of destroying or inhibiting the growth of bacteria, fungi, and other microorganisms

Bayesian network: a machine-learning approach used to explore probabilistic relationships among variables of interest

Bioavailability: potential for chemical absorption and distribution throughout the body and into cells, or the extent of chemical accessibility at a physiologically active site

Biocide: in European legislation, a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism by chemical or biological means (a similar but subtly different definition is used by the EPA)

Biomarker: a biological molecule found in blood, other body fluid, or tissues that can be measured and that may provide a sign of toxicity or disease

Biotransformation: the process in a living system of converting a substance to a different substance

Corneal epithelial cells: structural cells from the cornea, the transparent front part of the eye

Cryopreserved cells: cells preserved by cooling to subfreezing temperatures while avoiding damage caused by formation of ice; cryopreservation can be used to preserve cells extracted from tissues for later use

Cytochrome p450 enzymes: a group of enzymes that alter the structure of drugs and other molecules

Cytotoxic: the ability of a substance to kill or harm cells

Developmental toxicity: effects observed in offspring that occur as a result of chemical exposures of the pregnant mother. Developmental toxicity effects may be apparent at birth or emerge later in the offspring’s life.

Dosimetry: calculation of dose level or exposure concentration

Ecotoxicity testing: refers both to the assessment of chemical effects on fish, birds, or other wild organisms and testing of soil, sediment, or effluents for the presence of toxic compounds

Endocrine disruptor: a natural or man-made substance that may interfere with the endocrine system and produce adverse health effects

Estrogen: a class of hormones, produced largely by the ovaries, that serve as the primary female hormones

Estrogen receptor (ER): a protein molecule to which an estrogen or estrogen-like substance can attach. This interaction produces a chemical signal or triggers a cellular response.

Ex vivo: refers to an assay using tissue that has been removed from a multicellular organism and conducted while the tissue is still viable

Formulation: a mixture of chemicals prepared according to a specific procedure to ensure a desired effect when used, improve handling properties, or achieve other desired product goals

Harmonization: the act of making systems or laws similar among different companies, countries, etc., so the organizations using those systems or laws can operate more easily within the different venues

Hazard classification: assignment of a substance to a category according to results of toxicity testing, most often for labeling purposes

High throughput screening (HTS): a testing approach that uses robotics, liquid-handling devices, detectors, and associated software to quickly conduct a large number of chemical or biochemical tests

Immunotoxicity: an adverse effect caused by a substance (an “immunotoxicant”) that disrupts the normal function of the immune system

In chemico: refers to a test method that measures the interaction of a test chemical with protein or DNA molecules rather than living cells

In silico: refers to analyses that are carried out on a computer or via computer simulation

In vitro: refers to assays that are carried out in an artificial system such as a test tube or assay plate using small single-celled or multicellular organisms, cultured cells, or cellular components

In vitro to in vivo extrapolation (IVIVE): an analysis conducted to relate the test chemical concentration causing a response in an in vitro system to concentrations that result in human or animal (“in vivo”) illness or injury at the target tissue

In vivo: refers to assays carried out using multicellular organisms, typically rodents or other mammals

Integrated approaches to testing and assessment (IATA): an approach that considers all available relevant information about a substance in a weight-of-evidence assessment to inform a regulatory decision regarding hazard or risk or indicate that specific additional tests are needed

Integrated testing strategy: a type of IATA consisting of a fixed data interpretation procedure combining data from a specific set of sources in a parallel, structured, and reproducible manner

LD50: in traditional animal tests, the dose that causes death in 50% of the animals tested; a value used to categorize toxic substances and determine the hazard phrases used on product labels

Machine learning: the study and construction of computer algorithms that, once trained on a set of data, can make predictions or decisions about a different set of data; a Bayesian network is one type of these

Macromolecule: a large molecule, such as a protein, that consists of many smaller molecules linked together

Metabolism: the sum of the processes by which a particular substance is handled in a living organism, such as assimilation and incorporation or detoxification and excretion

Microphysiological organ systems: in vitro models of organs composed of cells and structural materials that are designed to reproduce the function of living organs; also referred to as “organs-on-a-chip”

Murine histamine sensitization test (HIST): a safety test performed using mice to ensure that pertussis toxin in acellular pertussis vaccines has been effectively inactivated

Nanomaterials: a substance made up of particles that measure no more than 100 nanometers in at least one dimension

Ocular corrosive: a substance that causes permanent eye tissue damage

Ocular irritant: a substance that causes temporary eye tissue damage. A severe irritant produces damage persisting 21 days after application or causes serious physical decay of vision.

Pharmacokinetic model: a mathematical model created to describe the process of absorption, distribution, metabolism, and excretion of a chemical through the body. “One-compartment” models treat all organs as a single unit, while “physiologically based” models are usually multi-compartment models with separate compartments corresponding to individual or combined organs and being interconnected by blood flows.

Physicochemical properties: referring to the physical or chemical properties of a substance

Quantitative structure-activity relationship (QSAR) models: classification models that predict the activities of chemicals with unknown properties by relating them to properties of known chemicals

Read-across: a computational technique that uses toxicity data from a known (“source”) chemical to predict toxicity for another (“target”) chemical, usually but not always on the basis of structural similarity

Reduction alternative: a test method that requires fewer animals

Reference data: data from an accepted test method that can be used to assess the performance of a new test method designed to measure an analogous effect

Reference chemical: a chemical that causes a specific well-characterized biological effect and therefore can be used to assess the performance of a test method designed to measure that effect. Reference chemicals should represent the classes of chemicals for which a test method is proposed to be used and cover the range of expected responses.

Refinement alternative: a test method that modifies procedures to enhance animal well-being and lessen or avoid pain and distress in animals

Relevance: the extent to which a test method accurately measures a biological effect of interest in a species of interest

Reliability: the extent to which a test method can be performed reproducibly over time

Replacement alternative: a test method that replaces animals with a non-animal system or one animal species with a phylogenetically lower one

Risk assessment: the process of characterizing the potential risk posed by a chemical, taking into consideration the hazards posed by the chemical, the dose of the chemical needed to cause health problems, and the probability of exposure at that dose

Semipermeable membrane: a barrier that allows some molecules to pass through but not others

Sensitivity: the ability of a new test method to correctly classify a substance as having a particular activity

Skin sensitization: a hypersensitivity that occurs when a susceptible person comes in direct skin contact with an allergen, termed a “skin sensitizer.” Once sensitized, a person may have a secondary immune response when exposed to the same allergen again.

Skin sensitization potency: the relative amount of a substance that produces a skin sensitization reaction

Specificity: the ability of a new test method to correctly classify a substance as not having a particular activity

Thrombogenicity: the tendency of a substance (in this case a medical device) to induce blood clot formation

Tier 1 test: in the Endocrine Disruptor Screening Program, a test performed to identify substances that have the potential to interact with the endocrine system. Chemicals exhibiting the potential to interact with the estrogen, androgen, or thyroid hormone systems will proceed to Tier 2 testing, which identifies the adverse effect caused by the chemical and establishes a quantitative relationship between the chemical dose and the adverse effect.

Titration (virology): inoculation of an animal with a virus preparation to assess the potency of the preparation for use in vaccine testing

Toxicant: a toxic or poisonous substance

Transcription: the process by which DNA directs production of specific proteins in cells, in this case in response to chemical exposure

Transcriptomics: studies that consider the complete set of RNA transcripts produced in a cell or tissue under specific circumstances, such as in response to chemical treatment

Uterotrophic assay: an assay conducted in female rodents that measures the estrogenic activity of a chemical by assessing the chemical’s effect on the weight of the uterus

Vaccination-challenge assay: a potency test requiring the vaccination of animals followed by infection with a virulent pathogen to assess the protection afforded by a specific vaccine

Validation: a process by which the reliability and relevance of a test method are established for its intended application

Viability: ability to live, especially under specific conditions