IUPAC Glossary of Terms Used in Toxicology – A
| 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 |
abiological
See abiotic
abiotic
abiological
Not associated with living organisms.
abiotic degradation
Process in which a substance is converted to simpler products by
physical or chemical mechanisms: examples include hydrolysis and
photolysis.
abiotic transformation
Process in which a substance in the environment is modified by
non-biological mechanisms.
abortifacient
Substance causes pregnancy to end prematurely and causes an
abortion.
absolute lethal concentration
(LC100)
Lowest concentration
of a substance in an environmental medium which kills 100 % of
test organisms or species under defined conditions.
Note: This value is dependent on the number of organisms used in
its assessment.
absolute lethal dose (LD100)
Lowest amount of a substance which kills 100 % of test animals
under defined conditions. Note: This value is dependent on the
number of organisms used in its assessment.
absorbance, A
Logarithm of the ratio of incident to transmitted radiant power
through a sample (excluding the effects of sample cell walls).
Depending on the base of the logarithm, a decadic and Napierian
absorbance are used. Symbols: A,
A10, Ae. This quantity is
sometimes called extinction, although the term extinction, better
called attenuance, is reserved
for the quantity which takes into account the effects of
luminescence and scattering as well.
Corrected from [3]
Note: When natural logarithms are used, the Napierian absorbance
is the logarithm to the base e of the incident spectral radiant power, essentially monochromatic, divided by
the transmitted spectral radiant power, Pλ.
absorbed dose (of a substance)
internal dose
Amount (of a substance) taken up by an organism or into organs or
tissues of interest.
See absorption,
systemic
absorbed dose (of radiation), D
Energy imparted by ionizing radiation to a specified volume of
matter divided by the mass of that volume.
absorptance (in chemistry), α
Ratio of the absorbed to the incident radiant power. Also called
absorption factor. When
α ≤ 1, α ≈ Ae, where
Ae is the Napierian absorbance.
[3]
See also absorbance
- Process of one material (absorbate) being retained by another (absorbent). Note: The process may be the physical solution of a gas, liquid, or solid in a liquid, attachment of molecules of a gas, vapor, liquid, or dissolved substance to a solid surface by physical forces, etc.
- Transfer of some or all of the energy of radiation to matter
which it traverses. Note: Absorption of light at bands of
characteristic wavelengths is used as an analytical method in
spectrophotometry to identify the chemical nature of molecules,
atoms or ions and to measure the concentrations of these
species.
Corrected from [3]
absorption (in biology)
uptake Penetration of a substance into an organism and its cells
by various processes, some specialized, some involving
expenditure of energy (active transport), some involving a
carrier system, and others involving passive movement down an
electrochemical gradient.
Note: In mammals absorption is
usually through the respiratory tract, gastrointestinal tract,
or skin into the circulatory system and from the circulation into
organs, tissues and cells.
[2]
absorption (of radiation)
Phenomenon in which radiation transfers some or all of its energy
to matter which it traverses.
[3]
absorption, systemic
Uptake to the
blood and transport via the blood of a substance to an organ or
compartment
in the body distant from the site of absorption.
[2]
absorption coefficient (in biology)
absorption factor
Ratio of the absorbed quantity (uptake) of a
substance to the administered quantity (intake).
Note: For exposure by way of the respiratory tract, the
absorption coefficient is the ratio of the absorbed amount to the
amount of the substance (usually particles) deposited (adsorbed)
in the lungs.
absorption factor
See absorptance (in
chemistry), absorption
coefficient (in biology)
abuse (of drugs, substances, solvents
etc.)
Improper use of drugs or other substances.
acaricide
Substance intended to kill mites, ticks or other Acaridae.
acceptable daily intake (ADI)
Estimate by JECFA of the amount of a food additive, expressed on
a body weight basis, that can be ingested daily over a lifetime
without appreciable health risk.
Note 1: For calculation of ADI, a standard body mass of 60 kg is
used
Note 2: Tolerable Daily Intake (TDI) is the analogous term used
for contaminants.
[2]
acceptable daily intake (ADI) not
allocated
See 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”,
Note: Calculated risk of an increase of one case in a million
people per year for cancer is usually considered to be
negligible.
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.
- 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.
- In animal tests - allowing an animal to adjust to its environment prior to undertaking a study.
accumulation (in biology)
See bioaccumulation
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.
acid dissociation constant,
Ka
Equilibrium constant for the following reaction of an acid
HB:
where co = 1 mol dm-3 is the
standard amount concentration and activity coefficients have been
neglected.
Note 1: This constant, because activity coefficients are
neglected, is valid at a specified ionic strength. The
thermodynamic dissociation constant is found by suitable
extrapolation of the conditional constant to zero ionic strength.
Note that it is defined as a dimensionless quantity, but
sometimes it is given dimensions by omitting the standard amount
concentration.
Note 2: Because this constant differs for each acid and varies
over many degrees of magnitude, the acidity constant is often
represented by the additive inverse of its common logarithm,
represented by the symbol pKa (using the same
mathematical relationship as [H+] is to pH), viz.:
In general, a larger value of Ka (or a smaller value of pKa) indicates a stronger acid, since the extent of dissociation is larger at the same concentration.
[4]
acidosis
antonym alkalosis
Pathological condition in which the hydrogen(1+) (hydron) amount
concentration of body fluids is above normal and hence the pH of
blood falls below the reference interval.
- 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.
- 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 (abiotic)
Conversion of
a xenobiotic to
a more toxic derivative
by modification not involving biological catalysis.
activation (in biology)
See bio-activation
active ingredient
Component of a mixture responsible for the biological effects of
the mixture.
Compare inert
ingredient
active metabolite
Metabolite
causing biological and (or) toxicological effects.
After [2]
See metabolite
active transport
Movement of a substance across a cell membrane against an
electrochemical gradient, in the direction opposite to normal
diffusion and requiring the expenditure of energy.
antonym chronic
- Of short duration, in relation to exposure or
effect; the effect usually shows a rapid onset.
Note: In regulatory toxicology, ‘acute’ refers to studies where dosing is either single or limited to one day although the total study duration may extend to two weeks to permit appearance of toxicity in susceptible organ systems. - In clinical medicine, sudden and severe, having a rapid
onset.
After [2]
acute effect
Effect of finite duration 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. Note: Acute effects may occur
continuously following continuous dosing or repeatedly following
repeated dosing.
After [2]
acute exposure
antonym chronic
exposure
Exposure of
short duration.
[2]
See acute,
exposure
antonym chronic toxicity
- Adverse effects of finite duration occurring within a short time (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 of a starting point (which may be exposure to the toxicant, or loss of reserve capacity, or developmental change etc.).
- Ability of a substance to cause adverse effects within a short time of
dosing or exposure.
[2]
- 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.
- Process by which an organism stabilizes its physiological
condition after an environmental change.
Note: If this process exceeds the homeostatic range, it becomes pathological and results in symptoms of disease (adverse effects).
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).
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.
additive effect
Consequence which follows exposure to two
or more physico-chemical agents which act jointly but do not
interact: the total effect is the simple sum of the effects of
separate exposures to the agents under the same conditions.
[2]
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 change in connectivity, but no loss,
of atoms within the moieties A and B.
Note 1: Stoichiometries other than 1:1 are also possible, e.g. a
bis-adduct (2:1). An ‘intramolecular adduct’ can be
formed when A and B are groups contained within the same
molecular entity.
Note 2: This is a general term which, whenever appropriate,
should be used in preference to the less explicit
term complex. It is also used specifically for products
of an addition reaction. [3]
adenocarcinoma
Malignant tumor originating
in glandular epithelium or
forming recognizable glandular structures.
adenoma
Benign
tumor
occurring in glandular epithelium or
forming recognizable glandular structures.
- In pharmacology, a substance added to a drug to speed or increase the action of the main component.
- In immunology, a substance (such as aluminum hydroxide) or an organism (such as killed mycobacterium) 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
Secreting adrenaline (epinephrine) and (or) related substances;
in particular referring to sympathetic nerve fibers.
See sympathomimetic
adsorption
Increase in the concentration
of a substance at the interface of a condensed and a liquid or a
gaseous layer owing to the operation of surface forces.
[2]
See also interfacial
layer
adsorption factor
Ratio of the amount of substance adsorbed at the interface of a
condensed and a liquid or gaseous phase to the total amount of
the substance available for adsorption.
[2]
adstringent
See astringent
advection (in environmental chemistry)
Process of transport of a substance in air or water solely by
mass motion.
[2]
adverse effect
Change in biochemistry, physiology, growth, development
morphology, behavior, 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
other environmental influences.
After [2]
adverse event
Occurrence which causes an adverse
effect.
Note: An adverse event in clinical studies is any untoward
reaction in a human subject participating in a research project;
such an adverse event, which may be a psychological reaction,
must be reported to an institutional review board.
aerobe
Organism which requires dioxygen for respiration and hence for
growth and life.
aerodynamic diameter (of a particle)
Diameter of a spherical particle with relative density equal to
unity which has the same settling velocity in air as the particle
in question.
aerosol
Mixture of small particles (solid, liquid or a mixed variety) and
a carrier gas
(usually air).
Note 1: Owing to their size, these particles (usually less than
100 µm and greater than 0.01 µm in diameter) have a
comparatively small sedimentation velocity and hence exhibit some
degree of stability in the earth’s gravitational field.
Note 2: An aerosol may be characterized by its chemical
composition, its radioactivity, the particle size distribution,
the electrical charge and the optical properties.
[2]
aetiology
See etiology
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.
agonist
antonym antagonist
Substance which binds to cell receptors
normally responding to a naturally occurring substance and which
produces an effect similar to that of the natural substance.
Note 1: A partial agonist activates a receptor but does not cause
as much of a physiological change as does a full agonist.
Note 2: A co-agonist works together with other co-agonists to
produce a desired effect.
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.
- Network of organizations which monitor air pollution.
- Group of measures or processes used to minimize or prevent air pollution.
albuminuria
Presence of albumin, derived from plasma, in the urine.
algicide algaecide
Substance intended to kill algae.
aliquot (in analytical chemistry)
Known amount of a homogeneous material, assumed to be taken with
negligible sampling
error.
Note 1: The term is usually applied to fluids.
Note 2: The term “aliquot” is usually used when the
fractional part is an exact divisor of the whole; the term
“aliquant” has been used when the fractional part is
not an exact divisor of the whole (e.g., a 15 mL portion is an
aliquant of 100 mL).
Note 3: When an aliquot is taken of a laboratory sample or test
sample or the sample is otherwise subdivided, the samples have
been called split samples.
[2]
alkalosis
antonym acidosis
Pathological condition in which the hydrogen(1+) (hydron)
substance concentration of body fluids is below normal and hence
the pH of blood rises above the reference interval.
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.
allergen
Immunostimulant antigenic substance which may or may not cause a
clinically significant effect but which is capable of producing
immediate 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.
- Pertaining to a systematic relationship between growth rates
of different parts of an organism and its overall growth
rate.
[2] - Pertaining to a systematic relationship between size, shape, and metabolism in different species.
allometric growth
Regular and systematic pattern of growth such that the mass or
size of any organ or part of a body can be expressed in relation
to the total mass or size of the entire organism according to the
allometric equation:
Y = bχα where
Y = mass of the organ, χ = mass of the organism, α =
growth coefficient of the organ, and b = a constant.
[2]
- Adjustment of data to allow for change in proportion between an organ or organs and other body parts during the growth of an organism.
- Adjustment of data to allow for differences and make
comparisons between species having dissimilar characteristics,
e.g., in size, shape, and metabolism.
After [2]
allometry (in biology)
Measurement of the rate of growth of a part or parts of an
organism relative to the growth of the whole organism.
[2]
allomone
Semiochemical
that is produced by an organism inducing a response in an
organism of another species that is favorable to the emitter.
See kairomone,
synomone
all-or-none effect
See quantal
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.
ambient standard
See 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 (see microsome) to
allow metabolic transformation of mutagen precursors to active
derivatives.
amnesic shellfish poisoning (ASP)
Serious illness which is a consequence of consumption of bivalve
shellfish (mollusks) such as mussels, oysters and clams that have
ingested, by filter feeding, large quantities of micro-algae
containing domoic acid; acute symptoms include vomiting,
diarrhea, and in some cases, confusion, loss of memory,
disorientation and even coma.
amplification (of genes)
See gene
amplification
anabolism
antonym catabolism
Biochemical processes by which smaller molecules are joined to
make larger molecules.
anaemia
See anemia.
anaerobe
antonym aerobe
Organism which does not require dioxygen for life.
Note: Obligate (strict) anaerobes grow only in the absence of
dioxygen. Facultative anaerobes can grow either in the presence
or in the absence of dioxygen.
anaerobic
antonym aerobic
Not requiring dioxygen.
anaesthetic
See anesthetic
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)
Study designed to examine associations, commonly putative or
hypothesized causal relationships.
anaphylactoid
Of or resembling anaphylaxis.
anaphylaxis
Life threatening type 1 hypersensitivity allergic reaction (see
allergy) occurring in a person or animal
exposed to an antigen or
hapten to which
they have previously been sensitized.
Note: Consequences of the reaction may include angio-edema,
vascular collapse, shock, and respiratory distress.
anaplasia
Loss of normal cell differentiation, a feature characteristic of
most malignancies.
anemia
Condition in which there is a reduction in the number of red
blood cells or amount of hemoglobin per unit volume of blood
below the reference interval for a similar individual of the
species under consideration, often causing pallor and
fatigue.
anesthetic
Substance which produces loss of feeling or sensation: general
anesthetic produces loss of consciousness; local or regional
anesthetic renders a specific area insensible to pain.
aneuploid
Cell or organism with missing or extra chromosomes or parts of
chromosomes
and thus an abnormal number of chromosomes which is not an exact
multiple of the haploid number.
anoxia
Strictly total absence of oxygen but sometimes incorrectly used
instead of hypoxia to mean
a decreased oxygen supply in tissues.
antagonism (in toxicology)
Combined effect of two or more factors which is smaller than the
solitary effect of any one of those factors.
Note: In bioassays, the
term may be used when a specified effect is produced by
exposure to
either of two factors but not by exposure to both together.
antagonist (in
toxicology)
antonym agonist
Substance which binds to a cell receptor normally responding to a
naturally occurring substance and which prevents a response to
the natural substance.
antihelminth
helminthagogue
helminthic
vermifuge
- n., Substance intended to kill or cause the expulsion of parasitic intestinal worms, such as helminths.
- adj., Acting to expel or kill parasitic intestinal worms.
anthracosis (coal miners' pneumoconiosis)
Form of pneumoconiosis
caused by accumulation of anthracite carbon deposits in the lungs
due to inhalation of smoke or coal dust.
- Caused by or influenced by human activities.
- Describing a conversion factor used to calculate a
dose or concentration
affecting a human that has been derived from data obtained with
another species, e.g. the rat.
[2]
anti-adrenergic
See 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 (immunoglobulin)
produced by the immune system in response to exposure to an
antigenic molecule and characterized by its specific binding to a
site on that molecule (antigenic determinant or epitope).
[3]
- adj., Preventing transmission of parasympathetic (acetylcholine releasing) nerve impulses.
- n., Substance which prevents transmission of parasympathetic nerve impulses.
anticholinesterase
See cholinesterase
inhibitor
anticoagulant
Substance which prevents blood clotting, e.g., warfarin.
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 (epitope) 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.
antihistamine
Substance that blocks or counteracts the action of histamine.
antihelminth
See 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.
- n., Substance inhibiting or preventing the actions of muscarine and muscarine-like agents, e.g., atropine, on the muscarinic acetylcholine receptors.
- adj., Inhibiting or preventing the actions of muscarine and muscarine-like agents on the muscarinic acetylcholine receptors.
antimycotic
fungicide
Substance used to kill a fungus or to inhibit its growth.
- n., Substance inhibiting or preventing the actions of nicotine and nicotine-like agents, e.g., suxamethonium chloride, on the nicotinic acetylcholine receptors.
- adj. Inhibiting or preventing the actions of nicotine and nicotine-like agents on the nicotinic acetylcholine receptors.
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, e.g., an antimetabolite that inhibits metabolic
inactivation of the pesticide.
antiserum
Serum containing antibodies to a
particular antigen either because
of immunization or after an infectious disease.
Note: Usually the antibodies are polyclonal.
antiviral
See virucide
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.
aphid
Common name for a harmful plant parasite in the family Aphididae,
some species of which 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.
apopto/sis n., tic
adj.
Active process of programmed cell death, requiring metabolic
energy, often characterized by fragmentation of DNA, and cell
deletion without associated inflammation.
[2]
See necrosis
arboricide
Substance intended to kill trees and shrubs.
area source
Widespread origin of emissions.
area under the concentration-time curve
See area under the
curve
area under the curve (AUC)
Area between a curve and the abscissa (horizontal axis), i. e.,
the area underneath the graph of a function: often, the area
under the tissue (plasma)
concentration
curve of a substance expressed as a function of time.
[2]
area under the moment curve (AUMC)
Area between a curve and the abscissa (horizontal axis) in a plot
of (concentration
x time) versus time.
[2]
argyria
argyrosis
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.
arrhythmia
Any variation from the normal rhythm of the heartbeat.
arseniasis
Chronic arsenical poisoning.
artefact
Observation, effect, or result which is inaccurate because it is
produced by the methodology used in scientific investigation or
by experimental error
arteriosclerosis
Hardening and thickening of the walls of the arteries.
arthralgia
Pain in a joint.
arthritis
Chronic
inflammation
of a joint, usually accompanied by pain and often by changes in
structure.
arthropathy
arthrosis
Disease of a joint.
arthrosis
Joint or articulation.
asbestosis
Form of pneumoconiosis
caused by inhalation of asbestos fibers.
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.
Note: Examples include both physical (nitrogen gas) and chemical
(carbon monoxide) asphyxiants.
- Process of quantitative or qualitative analysis of a component of a sample.
- Results of a quantitative or qualitative analysis of a component of a sample.
assimilation
Uptake and incorporation of substances by a living organism.
asthenia
Weakness; lack or loss of strength.
asthma
Chronic respiratory disease characterized by bronchoconstriction,
excessive mucus secretion and edema of the
pulmonary alveoli, resulting in difficulty in breathing out,
wheezing, and cough.
- Adj. Causing contraction, usually locally after topical application.
- 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 co-ordination.
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, involving a
decrease in size and (or) numbers of cells.
attenuation (in genetics)
Regulation of gene expression in
bacteria by premature termination of transcription
of a biosynthetic operon.
attractant
Substance which attracts animals. Some attractants fulfill
natural biological functions such as mating or predation: others
may be used to attract animals for monitoring or for control.
See also pheromone
attributable risk
Part of a risk that is
identified as due to exposure to a defined substance.
[2]
auto-immune 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, systemic lupus erythematosus, and scleroderma.
auto-oxidation
See autoxidation
autophagosome
Membrane-bound body (secondary lysosome) in
which parts of the cell are digested.
autopsy
necropsy
Post-mortem examination of the organs and body tissue to
determine cause of death or pathological condition.
autosome
Any chromosome other than a sex chromosome.
autoxidation
Reaction with dioxygen at moderate temperatures.
autoxidation (in food chemistry)
Apparently spontaneous, usually slow reaction of foodstuff
components with dioxygen in an aerobic environment at moderate
temperatures.
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.
avicide
Substance intended to kill birds.
axenic animal
See germ-free
animal
- Absence of live motile spermatozoa in semen.
- Failure to form live spermatozoa.