CLINICAL
CHEMISTRY DIVISION
COMMISSION ON TOXICOLOGY
Glossary for chemists of terms used in toxicology
(IUPAC Recommmendations 1993)
Alphabetical entries
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A
abiological: See SN abiotic
abiotic: Not associated with living organisms.
SN abiological.
abiotic transformation: Process in which a substance in the
environment is modified by non-biological mechanisms.
RT biotransformation.
IPCS, 1987
absolute lethal concentration
(LC100): Lowest concentration of a substance in an environmental
medium which kills 100 % of test organisms or species under defined
conditions. This value is dependent on the number of organisms used
in its assessment.
WHO, 1979
absolute lethal dose (LD100):
Lowest amount of a substance which kills 100 % of test animals under
defined conditions. This value is dependent on the number of organisms
used in its assessment.
absorbed dose (of a substance):
Amount of a substance absorbed into an organism or into organs and tissues
of interest.
absorbed dose (of radiation): Energy imparted to matter in a
suitably small element of volume by ionizing radiation divided by the
mass of that element of volume. The SI unit for absorbed dose is joule
per kilogram (J kg-1) and its special name is gray (Gy).
ISO, 1972
RT ionizing radiation.
absorption (biological):
Process of active or passive transport of a substance into an organism:
in the case of a mammal or human being, this is usually through the
lungs, gastrointestinal tract, or skin.
absorption (in colloid and surface chemistry): Process whereby,
when two phases are brought into contact, a particular component is
transferred from one phase to the other.
PAC, 1972
absorption (of radiation): Phenomenon in which radiation transfers
some or all of its energy to matter which it traverses.
ISO, 1972
absorption coefficient (in biology): Ratio of the absorbed amount
(uptake)of a substance to the administered amount (intake): for exposure
by way of the respiratory tract, the coefficient is the ratio of the
absorbed amount to the amount of the substance (usually particles) deposited
(adsorbed) in the lungs.
RT absorbed dose.
SN absorption factor.
IRPTC, 1982
abuse (of drugs, substances, solvents etc.): Improper use of
drugs or other substances.
RT "glue sniffing", solvent
abuse, "solvent sniffing".
acaricide: Substance intended to kill mites, ticks or other
Acaridae.
acceptable daily intake (ADI):
Estimate of the amount of a substance in food or drinking water, expressed
on a body mass basis (usually mg/kg body weight), which can be ingested
daily over a lifetime by humans without appreciable health risk. For
calculation of the daily intake per person, a standard body mass of
60 kg is used. ADI is normally used for food additives (tolerable daily
intake is used for contaminants).
WHO, 1991
RT tolerable daily intake.
acceptable daily intake (ADI) not allocated: See SN no
acceptable daily intake allocated.
acceptable residue level of an antibiotic: Acceptable concentration
of a residue which has been established for an antibiotic found in human
or animal foods.
acceptable risk: Probability of
suffering disease or injury which is considered to be sufficiently small
to be "negligible".
PS tolerable risk.
RT accepted risk, negligible risk,
risk de minimis.
accepted risk: Probability of suffering
disease or injury which is accepted by an individual.
accidental exposure: Unintended contact with a substance or
change in the physical environment (including for example radiation)
resulting from an accident.
acclimatization (biological):
1. Processes, including selection and adaptation, by which a population
of micro-organisms
develops the ability to degrade a substance, or develops
a tolerance to it.
2. In animal tests - allowing an animal to adjust to its environment
prior to undertaking a
study.
accumulation: Successive additions
of a substance to a target organism, or organ, or to part of the environment,
resulting in an increasing amount or concentration of the substance
in the organism, organ, or environment.
WHO, 1989a
accuracy: Quantity referring to the differences between the
mean of a set of results or an individual result and the value which
is accepted as the true or correct value for the quantity measured.
Gold, Loening, McNaught and Sehmi, 1987
RT precision.
acidosis: Pathological condition in which
the hydrogen ion substance concentration of body fluids is above normal
and hence the pH of blood falls below the reference interval.
AN alkalosis.
action level:
1. Concentration of a substance in air, soil, water or other defined
medium at which specified
emergency counter-measures, such as the seizure and destruction
of contaminated materials,
evacuation of the local population or closing down the
sources of pollution, are to be
taken.
2. Concentration of a pollutant in air, soil, water or other defined
medium at which some kind
of preventive action (not necessarily of an emergency nature)
is to be taken.
activation: See NT bioactivation.
acute:
1. Short-term, in relation to exposure or effect. In experimental toxicology,
"acute" refers
to studies of two weeks or less in duration (often less
than 24 h).
AN chronic
2. In clinical medicine, sudden and severe, having a rapid onset.
acute effect: Effect of short duration
and occurring rapidly (usually in the first 24 h or up to 14 d) following
a single dose or short exposure to a substance or radiation.
acute toxicity:
1. Adverse effects occurring within a short time (usually up to 14 d)
after administration of
a single dose (or exposure to a given concentration)of
a test substance or after multiple
doses (exposures), usually within 24 h.
2. Ability of a substance to cause adverse effects within a short time
of dosing or exposure.
AN chronic toxicity.
acute toxicity test: Experimental
animal study to determine what adverse effects occur in a short time
(usually up to 14 d) after a single dose of a substance or after multiple
doses given in up to 24h.
RT limit test, median
lethal dose (LD50).
adaptation:
1. Change in an organism, in response to changing conditions of the
environment (specifically
chemical), which takes place without any irreversible disruptions
of the given biological
system and without exceeding normal (homeostatic) capacities
of its response.
2. Process by which an organism stabilizes its physiological condition
after an environmental
change.
RT acclimatization.
added risk: Difference between the incidence of an adverse effect
in a treated group (of organisms or a group of exposed humans) and a
control group (of the same organisms or the spontaneous incidence in
humans).
IRIS, 1986
addiction: Surrender and devotion to
the regular use of a medicinal or pleasurable substance for the sake
of relief, comfort, stimulation, or exhilaration which it affords; often
with craving when the drug is absent.
PS dependence.
additive effect: Consequence which
follows exposure to two or more physico-chemical agents which act jointly
but do not interact: commonly, the total effect is the simple sum of
the effects of separate exposure to the agents under the same conditions.
Substances of simple similar action may show dose or concentration addition.
RT antagonism, combined
effect of poisons, potentiation,
synergism.
adduct: New chemical species AB, each molecular entity of which
is formed by direct combination of two separate molecular entities A
and B in such a way that there is no change in connectivity of atoms
within their moieties A and B. Stoichiometries other than 1:1 are also
possible. An intramolecular adduct can be formed when A and B
are groups contained
within the same molecular entity.
Gold, Loening, McNaught and Sehmi, 1987
adenocarcinoma: Malignant tumour
originating in glandular epithelium or forming recognizable glandular
structures.
RT adenoma.
adenoma: Benign tumour occurring in glandular
epithelium or forming recognizable glandular structures.
RT adenocarcinoma.
adjuvant:
1. In pharmacology, a substance added to a drug to speed or increase
the action of the main
component.
2. In immunology, a substance (such as aluminium hydroxide) or an organism
(such as bovine
tuberculosis bacillus) which increases the response to
an antigen.
administration (of a substance): Application of a known amount
of a substance to an organism in a reproducible manner and by a defined
route.
adrenergic: See SN sympathomimetic
adsorption: Enrichment (positive adsorption, or briefly adsorption)
of one or more components in an interfacial layer.
Gold, Loening, McNaught and Sehmi, 1987
adverse effect: Change in morphology,
physiology, growth, development or lifespan of an organism which results
in impairment of functional capacity or impairment of capacity to compensate
for additional stress or increase in susceptibility to the harmful effects
of other environmental influences.
After IPCS, 1978
adverse event: Occurrence which causes an adverse effect.
aerobe: Organism which needs molecular
oxygen for respiration and hence for growth and life.
After Nagel et al. (eds), 1991
aerobic: Requiring molecular oxygen.
aerodynamic diameter (of a particle):
Diameter of a spherical particle of unit density which has the same
settling velocity in air as the particle in question.
IPCS, 1987
aerosol: Dispersion of liquid or solid material in a gas.
Gold, Loening, McNaught and Sehmi, 1987
aetiology:
1. Science dealing with the cause or origin of disease.
2. In individuals, the cause or origin of disease.
RT epidemiology.
after-effect of a poison: Ability of a poison to produce a change
in an organism after cessation of contact.
age sensitivity: Quantitative and qualitative age dependence
of an effect.
IRPTC, 1982
agonist: Substance which binds to cell
receptors normally responding to naturally occurring substances and
which produces a response of its own.
AN antagonist.
air pollution: Presence of substances
in the atmosphere resulting either from human activity or natural processes,
in sufficient concentration, for a sufficient time and under circumstances
such as to interfere with comfort, health or welfare of persons or to
harm the environment.
ISO, 1980
BT pollution.
air pollution control system:
1. Network of organizations which monitor air pollution.
2. Group of measures or processes used to minimize or prevent air pollution.
RT air pollution, pollution.
albuminuria: Presence of albumin, derived from plasma, in the
urine.
RT microalbuminuria, proteinuria.
algicide: Substance intended to kill algae.
alkalosis: Pathological condition in
which the hydrogen ion substance concentration of body fluids is below
normal and hence the pH of blood rises above the reference interval.
AN acidosis.
alkylating agent: Substance which introduces an alkyl substituent
into a compound.
allele: One of several alternate forms of a gene which occur
at the same relative position (locus) on homologous chromosomes and
which become separated during meiosis and can be recombined following
fusion of gametes.
RT gametes, meiosis.
Nagel et al. (eds), 1991
allergen: Antigenic substance capable of producing immediate
hypersensitivity.
RT allergy, antigen,
hypersensitivity.
allergy: Symptoms or signs occurring in
sensitized individuals following exposure to a previously encountered
substance (allergen) which would otherwise not cause such symptoms or
signs in non-sensitized individuals. The most common forms of
allergy are rhinitis, urticaria, asthma, and contact dermatitis.
RT immune response, hypersensitivity.
all-or-none effect: See SN
quantal effect.
RT stochastic effect.
alopecia: Baldness; absence or thinning of hair from areas of
skin where it is usually present.
alveol/us (pulmonary), -i pl., -ar adj.: Terminal
air sac of the lung where gas exchange occurs.
ambient: Surrounding (applied to environmental media such as
air, water, sediment or soil).
ambient monitoring: Continuous
or repeated measurement of agents in the environment to evaluate ambient
exposure and health risk by comparison with appropriate reference values
based on knowledge of the probable relationship between exposure and
resultant adverse health effects.
After Berlin, Yodaiken, and Henman,
1984
RT biological monitoring,
environmental monitoring,
monitoring.
ambient standard: See SN environmental
quality standard.
Ames test: In vitro test for mutagenicity using mutant
strains of the bacterium Salmonella typhimurium which cannot
grow in a given histidine-deficient medium: mutagens can cause reverse
mutations which enable the bacterium to grow on the medium. The test
can be carried
out in the presence of a given microsomal fraction (S-9) from rat liver
to allow metabolic transformation of mutagen precursors to active derivatives.
amplification (of genes): See gene
amplification.
anabolism: Biochemical processes by
which smaller molecules are joined to make larger molecules.
AN catabolism.
anaemia: Condition in which there is a
reduction in the number of red blood cells or amount of haemoglobin
per unit volume of blood below the reference interval for a similar
individual of the species under consideration, often causing pallor
and fatigue.
anaerobe: Organism which does not need molecular oxygen for
life. Obligate (strict) anaerobes grow only in the absence of oxygen.
Facultative anaerobes can grow either in the presence or in the absence
of molecular oxygen.
Nagel et al. (eds), 1991
AN aerobe.
anaerobic: Not requiring molecular oxygen.
anaesthetic: Substance which produces
loss of feeling or sensation: general anaesthetic produces loss of consciousness;
local or regional anaesthetic renders a specific area insensible to
pain.
analgesic: Substance which relieves pain, without causing loss
of consciousness.
analogue metabolism: Process
by which a normally non-biodegradable compound is biodegraded in the
presence of a structurally similar compound which can induce the necessary
enzymes.
analytic study (in epidemiology): Hypothesis-testing method
of investigating the association between a given disease or health state
or other dependent variable and possible causative factors. In an analytic
study, individuals in the study population are classified according
to
absence or presence (or future development) of specific disease and
according to attributes which may influence disease occurrence. Attributes
may include age, race, sex, other disease(s), genetic, biochemical,
and physiological characteristics, economic status, occupation, residence,
and various aspects of the environment or personal behaviour.
Three types of analytic study are: cross-sectional (prevalence), cohort
(prospective), and case control (retrospective).
Last, 1988
anaphylaxis: Severe allergic reaction occurring in a person
or animal exposed to an antigen or hapten to which they have previously
been sensitized.
RT antigen, hapten.
anaplasia: Loss of normal cell differentiation, a feature characteristic
of most malignancies.
RT malignancy.
anemia: See anaemia.
aneuploid: Cell or organism with missing or extra chromosomes
or parts of chromosomes.
anoxia: Strictly total absence of oxygen but sometimes used
to mean decreased oxygen supply in tissues.
antagonism: Combined effect of two
or more factors which is smaller than the solitary effect of any one
of those factors. In bioassays, the term may be used when a specified
response is produced by exposure to either of two factors but not by
exposure to both together.
RT synergism.
antagonist:
1. Substance that reverses or reduces the effect induced by an agonist.
2. Substance that attaches to and blocks cell receptors that normally
bind naturally occurring
substances.
AN agonist.
anthelmint(h)ic: Substance intended to
kill parasitic intestinal worms, such as helminths.
SN antihelminth.
anthracosis (coal miners' pneumoconiosis):
Form of pneumoconiosis caused by accumulation of carbon deposits in
the lungs due to inhalation of smoke or coal dust.
anthropogenic: Caused by or influenced
by human activities.
anti-adrenergic: See SN sympatholytic.
antibiotic: Substance produced by, and obtained from, certain
living cells (especially bacteria, yeasts and moulds), or an equivalent
synthetic substance, which is biostatic or biocidal at low concentrations
to some other form of life, especially pathogenic or noxious organisms.
antibody: Protein molecule produced by
the immune system (an immunoglobulin molecule) which can bind specifically
to the molecule (antigen or hapten) which induced its synthesis.
RT antigen, hapten,
immunoglobulin.
anticholinergic
1. adj., Preventing transmission of parasympathetic nerve impulses.
2. n., Substance which prevents transmission of parasympathetic nerve
impulses.
anticholinesterase: See SN cholinesterase
inhibitor.
anticoagulant: Substance which prevents clotting.
antidote: Substance capable of specifically counteracting or
reducing the effect of a potentially toxic substance in an organism
by a relatively specific chemical or pharmacological action.
antigen: Substance or a structural part
of a substance which causes the immune system to produce specific antibody
or specific cells and which combines with specific binding sites (epitopes)
on the antibody or cells.
After Nagel et al. (eds), 1991
RT antibody, epitope.
antihelminth: See SN anthelmint(h)ic.
antimetabolite: Substance, structurally similar to a metabolite,
which competes with it or replaces it, and so prevents or reduces its
normal utilization.
antimycotic: Substance used to kill a fungus or to inhibit its
growth.
SN fungicide.
antipyretic: Substance which relieves or reduces fever.
antiresistant: Substance used as an additive to a pesticide
formulation in order to reduce the resistance of insects to the pesticide.
IRPTC, 1982
antiserum: Serum containing antibodies to a particular antigen
either because of immunization or after an infectious disease.
aphasia: Loss or impairment of the power of speech or writing,
or of the ability to understand written or spoken language or signs,
due to a brain injury or disease.
aphicide: Substance intended to kill aphids.
BT insecticide.
aphid: Common name for a harmful plant parasite in the family
Aphididae: some species are vectors of plant virus diseases.
aplasia: Lack of development of an organ or tissue, or of the
cellular products from an organ or tissue.
apoptosis: Physiological process of programmed tissue death
(and disintegration) associated with normal development in animals.
RT necrosis.
arboricide: Substance intended to kill trees and shrubs.
area source: Widespread origin of
emissions.
RT point source.
argyria: Pathological condition characterized
by grey-bluish or black pigmentation of tissues (such as skin, retina,
mucous membranes, internal organs) caused by the accumulation of metallic
silver, due to reduction of a silver compound which has entered the
organism during (prolonged) administration or exposure.
SN argyrosis.
argyrosis: See SN argyria.
arrhythmia: Any variation from the normal rhythm of the heartbeat.
artefact: Finding or product of experimental or observational
techniques that is not properly associated with the system being studied.
arteriosclerosis: Hardening and thickening of the walls of the
arteries.
arthralgia: Pain in a joint.
arthralgia saturnia: Pain in a joint resulting from lead poisoning.
arthritis: Inflammation of a joint, usually accompanied by pain
and often by changes in structure.
asbestosis: Form of pneumoconiosis
caused by inhalation of asbestos fibres.
BT pneumoconiosis.
ascaricide: Substance intended to kill roundworms (Ascaridae).
asphyxia: Condition resulting from insufficient intake of oxygen:
symptoms include breathing difficulty, impairment of senses, and, in
extreme, convulsions, unconsciousness and death.
asphyxiant: Substance that blocks the transport or use of oxygen
by living organisms.
assay:
1. Process of quantitative or qualitative analysis of a component of
a sample.
2. Results of a quantitative or qualitative analysis of a component
of a sample.
assessment of exposure: See NT biological
assessment of exposure.
asthenia: Weakness; lack or loss of strength.
asthma: Chronic respiratory disease characterised by bronchoconstriction,
excessive mucus secretion and oedema of the pulmonary alveoli, resulting
in difficulty in breathing out, wheezing, and cough.
astringent:
1. Adj. Causing contraction, usually locally after topical application.
2. N. Substance causing cells to shrink, thus causing tissue contraction
or stoppage of secretions and discharges; such
substances may be applied to skin to harden and protect
it.
ataxia: Unsteady or irregular manner of walking or movement
caused by loss or failure of muscular coordination.
atherosclerosis: Pathological condition in which there is thickening,
hardening, and loss of elasticity of the walls of blood vessels, characterized
by a variable combination of changes of the innermost layer consisting
of local accumulation of lipids, complex carbohydrates, blood and blood
components, fibrous tissue and calcium deposits. In addition, the outer
layer becomes thickened and there is fatty degeneration of the middle
layer.
atrophy: Wasting away of the body or of an organ or tissue.
attenuation (in genetics): Regulation of gene expression in
bacteria by premature termination of transcription of a biosynthetic
operon.
attractant: Substance used to attract animals with the aim of
killing or sterilizing them.
BT pheromone.
attributable risk: Difference between the risk of exhibiting
a certain adverse effect in the presence of a substance and the same
risk in the absence of the substance.
BT risk.
Last, 1988
autoimmune disease: Pathological
condition resulting when an organism produces antibodies or specific
cells which bind to constituents of its own tissues (autoantigens) and
cause tissue injury: examples of such disease may include rheumatoid
arthritis, myasthenia gravis, and scleroderma.
RT allergy, antibody,
antigen, hypersensitivity,
immune response.
autophagosome: Membrane-bound body (secondary lysosome) in which
parts of the cell are digested.
autopsy: Post-mortem examination of the
organs and body tissue to determine cause of death or pathological condition.
RT biopsy.
SN necropsy.
auxotroph: Organism unable to synthesize an organic molecule
which is required for its growth: when the compound is given to the
organism with the other nutrients it requires, growth of the organism
may occur.
auxotrophy: Inability of a micro-organism to synthesize a particular
organic compound required for its growth.
Nagel et al. (eds), 1989
avicide: Substance intended to kill birds.
axenic animal: See SN germ
free animal.
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Alphabetical entries
A | B |
C | D | E
| F | G | H
| I | J | K
| L | M
N | O |
P | Q | R
| S | T | U
| V | W | X
| Y | Z