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Pure Appl. Chem.,
Vol. 65, No. 9, pp. 2003-2122, 1993.
CLINICAL
CHEMISTRY DIVISION
COMMISSION ON TOXICOLOGY
Glossary for chemists of terms used in toxicology
(IUPAC Recommmendations 1993)
Alphabetical entries
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lacrimator: Substance
that irritates the eyes and causes the production of tears or increases
the flow of tears.
larvicide: Substance intended to kill larvae.
laryngospasm: Reflex spasmodic closure of
the sphincter of the larynx, particularly the glottic sphincter.
larynx: Main organ of voice production, the
part of the respiratory tract between the pharynx and the trachea.
lassitude: Weakness; exhaustion.
latent period:
Delay between exposure to a disease-causing agent and the appearance
of manifestations of the disease: also defined as the period from
disease initiation to disease detection.
SN latency.
Last, 1988
lavage: Irrigation or washing out of a hollow
organ or cavity such as the stomach, intestine or the lungs.
laxative: Substance
that causes evacuation of the intestinal contents.
SN cathartic, purgative.
lesion:
1. Area of pathologically altered tissue.
2. Injury or wound.
3. Infected patch of skin.
lethal: Deadly; fatal; causing death.
lethal concentration:
Concentration of a potentially toxic substance in an environmental
medium that causes death following a certain period of exposure
(denoted by LC).
WHO, 1979
RT effective concentration,
lethal dose.
lethal dose: Amount
of a substance or physical agent (radiation) that causes death when
taken into the body by a single absorption (denoted by LD).
RT effective dose, lethal
concentration.
lethal synthesis:
Metabolic formation of a highly toxic compound from one that is
relatively non-toxic (bioactivation), often leading to death of
affected cells.
SN suicide metabolism.
leukaemia: Progressive, malignant disease
of the blood-forming organs, characterized by distorted proliferation
and development of leucocytes and their precursors in the bone marrow
and blood.
leukopenia: Reduced concentration of leukocytes
in the blood.
life-long exposure: Subjection to a potentially
toxic substance during the whole lifetime.
limacide: Substance
intended to kill mollusca including the gastropod mollusc, Limax.
limit recommended: See recommended limit.
limit test: Acute
toxicity test in which, if no ill-effects occur at a pre-selected
maximum dose, no further testing at greater exposure levels is required.
Brown, 1988
RT fixed dose test.
limit value (LV):
Limit concentration at or below which Member States of the European
Community must set their environmental quality standard and emission
standard for a particular substance according to Community Directives.
NT threshold limit value.
limited evidence:
According to the US EPA's guidelines for Carcinogen Risk Assessment,
"limited evidence" is a collection of facts and accepted scientific
inferences that suggests that an agent may be causing an effect,
but this suggestion is not strong enough to be considered established
fact.
IRIS, 1986
RT carcinogenicity,
classification according to IARC.
linearized multistage model: Sequence of
steps in which (a) a multistage model is fitted to tumour incidence
data; (b) the maximum linear term consistent with the data is calculated;
(c) the low-dose slope of the dose-response function is equated
to the coefficient of the maximum linear term; and (d) the resulting
slope is then equated to the upper bound of potency.
BT multistage model.
liposome: Originally a lipid droplet in the
endoplasmic reticulum of a fatty liver. Now applied to an artificially
formed lipid droplet, small enough to form a relatively stable suspension
in aqueous media and with potential use in drug delivery.
local effect: Circumscribed change occurring
at the site of contact between an organism and a toxicant.
RT systemic effect.
logit transformation: Mathematical transformation
that relates response to a stated dose or concentration of a toxicant
to the response in the absence of the toxicant by the formula:
Logit = lg [B/(B0-B)]
where B is the response to the stated dose or concentration and
B0 is the response in the absence of the toxicant. Plotting
the logit function against the logarithm of base 10 of the dose
or concentration usually gives a linear relationship.
long-term exposure: Continuous or repeated
exposure to a substance over a long period of time, usually of several
years in man, and of the greater part of the total life-span in
animals or plants.
IRPTC, 1982
SN chronic exposure.
lymphocyte: Animal
cell that interacts with a foreign substance or organism, or one
which it identifies as foreign, and initiates an immune response
against the substance or organism. There are two groups of lymphocytes,
B lymphocytes and T lymphocytes.
NT B lymphocyte, immune
response, T lymphocyte.
lymphoma: General term comprising tumours
and conditions allied to tumours arising from some or all of the
cells of lymphoid tissue.
lysimeter: Laboratory column of selected
representative soil or a protected monolith of undisturbed field
soil with which it is possible to sample and monitor the movement
of water and substances.
lysosome: Membrane-bound cytoplasmic organelle containing
hydrolytic enzymes.
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
Page last modified 12 September 2001.
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