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Pure Appl. Chem., Vol. 65, No. 9, pp. 2003-2122, 1993.



Glossary for chemists of terms used in toxicology
(IUPAC Recommmendations 1993)


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

death rate: Estimate of the proportion of a population which dies during a specified period. The numerator is the number of persons dying during the period; the denominator is the size of the population, usually estimated as the mid-year population. The death rate in a population is generally calculated by the formula:
10n (Number of deaths during a specified period) / (Number of persons at risk of dying during the period)
This rate is an estimate of the person-time death rate, the death rate per 10n person-years: usually n = 3. If the rate is low, it is also a good estimate of the cumulative death rate. This rate is also called the crude death rate.
Last, 1988
PS mortality, mortality rate.
decompensation: Explicit pathophysiological changes following compensation for adverse effects.
decontamination: Process of rendering harmless (by neutralization, elimination, removal etc.) a potentially toxic substance in the natural environment, laboratory areas, the workplace, other indoor areas, clothes, food, water, sewage etc.
defoliant: Substance used for removal of leaves by its toxic action on living plants.
dehydrogenase: Enzyme which catalyses oxidation of compounds by removing hydrogen.
delayed effect: Consequence occurring after a latent period following the end of exposure to a toxic substance or other harmful environmental factor.
SN latent effect.
1. Addition of methanol or acetone to alcohol to make it unfit for drinking.
2. Change in molecular structure of proteins so that they cannot function normally, often caused by splitting of hydrogen
   bonds following exposure to reactive substances or heat.
denitrification: Reduction of nitrates to nitrites, nitrous oxides or dinitrogen (N2) catalysed by facultative aerobic soil bacteria under anaerobic conditions.
Nagel et al. (eds),1990
dental fluorosis: Variety of tooth enamel malformations due to excessive fluoride exposure during dental development.
deoxyribonucleic acid (DNA): Constituent of chromosomes which stores the hereditary information of an organism in the form of a sequence of purine and pyrimidine bases: this information relates to the synthesis of proteins and hence it is a determinant of all physical and functional activities of the cell, and consequently of the whole organism.
RT ribonucleic acid (RNA).
1. A psychic craving for a drug or other substance which may or may not be accompanied by a physical dependency.
2. Reliance on a drug or other substance to maintain health.
PS addiction.
depilatory: Substance causing loss of hair.
1. Process by which a substance arrives at a particular organ or tissue site, for example the deposition of particles on
   the ciliated epithelium of the bronchial airways.
2. Process by which a substance sediments out of the atmosphere or water and settles in a certain place.
PS accumulation.
dermal: Pertaining to the skin.
SN cutaneous.
dermal irritation: Skin reaction resulting from a single or multiple exposure to a physical or chemical entity at the same site, characterised by the presence of inflammation; it may result in cell death.
dermatitis: Inflammation of the skin: contact dermatitis is due to local exposure and may be caused by irritation, allergy or infection.
descriptive epidemiology: Study of the occurrence of disease or other health-related characteristics in populations, including general observations concerning the relationship of disease to basic characteristics such as age, sex, race, occupation, and social class; it may also be concerned with geographic location. The major characteristics in descriptive epidemiology can be classified under the headings: individuals, time and place.
IPCS, 1987
desensitization: Suppression of sensitivity of an organism to an allergen to which the organism has been exposed previously.
1. Drying agent.
2. In agriculture, a substance used for drying up plants and facilitating their mechanical harvesting.
desorption: Opposite of adsorption; a decrease in the amount of adsorbed substance.
Gold, Loening, McNaught and Sehmi, 1987
desquamation: Shedding of an outer layer of skin in scales or shreds.
1. Process, or processes, of chemical modification which make a toxic molecule less toxic.
2. Treatment of patients suffering from poisoning in such a way as to promote physiological processes which reduce the
   probability or severity of harmful effects.
detoxification by haemosorption perfusion: Passage of a patient's blood through a set of columns filled with a haemosorbent (activated charcoal, ion-exchange resin, etc.): the purpose of the operation is to remove a toxic substance from the organism, particularly in an emergency.
RT haemoperfusion, haemosorption.
detriment: Estimated measure of the expected harm or loss associated with an adverse event, usually in a manner chosen to facilitate meaningful addition over different events. It is generally the integrated product of arbitrary values of risk and hazard and is often expressed in terms such as costs in US dollars, loss in expected years of life or loss in productivity, and is needed for numerical exercises such as cost-benefit analysis.
developmental toxicity: Adverse effects on the developing organism (including structural abnormality, altered growth, or functional deficiency or death) resulting from exposure prior to conception (in either parent), during prenatal development, or postnatally up to the time of sexual maturation.
IRIS, 1986
RT embryotoxicity, teratogenicity.
diaphoresis: Profuse perspiration.
diaphoretic: Causing profuse perspiration.
SN sudorific.
2,3-dimercaptopropan-1-ol: Metal chelator which has been used in the treatment of arsenic, antimony, gold, mercury and lead poisoning.
SN British anti-Lewisite, dimercaprol.
dimercaprol: See SN 2,3-dimercaptopropan-1-ol.
diploid: Chromosome state in which the chromosomes are present in homologous pairs. Normal human somatic (non-reproductive) cells are diploid (they have 46 chromosomes), whereas reproductive cells, with 23 chromosomes, are haploid.
RT haploid, meiosis, mitosis.
discharge: See SN emission.
discharge (effluent, emission) standard or release limit: Maximum amount of a pollutant released from a given source to a specified medium which is acceptable under specified circumstances.
WHO, 1979
discordance (genetic): Any difference in a character between individuals due to genetic differences such as may occur in dizygotic twins, or between matched pairs in a case cohort study.
AN concordance.
disease: Literally, dis-ease, lack of ease; pathological condition that presents a group of symptoms peculiar to it and which establishes the condition as an abnormal entity different from other normal or pathological body states.

discontinuous effect: See SN intermittent effect
disposition: Natural tendency shown by an individual or group of individuals, including any tendency to acquisition of specific diseases, often due to hereditary factors.
dissipation: Reduction in the amount of a pesticide or other compound which has been applied to plants, soil etc. (used when it is not clear whether this is by mineralization degradation, binding, or leaching).
distributed source: See SN area source.
RT point source.
1. Dispersal of a substance and its derivatives throughout the natural environment.
2. Dispersal of a substance within an organism, including metabolism, storage and excretion.
3. Final location of a substance within an organism after dispersal.
diuresis: Excretion of urine, especially in excess.
diuretic: Agent which increases urine production.
SN micturitic.
dosage: Dose expressed as a function of the organism being dosed and time, for example mg/(kg body weight)/day.
See dose.
dose-effect curve: Graph of the relation between dose and the magnitude of the biological change produced measured in appropriate units.
RT concentration-effect curve.
dose-effect relationship: Association between dose and the magnitude of a continuously graded effect, either in an individual or in a population or in experimental animals.
RT concentration-effect relationship.
dose-related effect: Situation in which the magnitude of a biological change is related to the dose.
AN non-dose-related effect.
dose-response curve: Graph of the relation between dose and the proportion of individuals in a population responding with an all-or-none effect.
RT concentration-response curve, response.
dose-response relationship: Association between dose and the incidence of a defined biological effect in an exposed population.
RT concentration-response relationship, response.
Draize test: Evaluation of materials for their potential to cause dermal or ocular irritation and corrosion following local exposure; generally using the rabbit model (almost exclusively the New Zealand White) although other animal species have been used.
drug: Any substance which when absorbed into a living organism may modify one or more of its functions. The term is generally accepted for a substance taken for a therapeutic purpose, but is also commonly used for abused substances.
SN medicine, pharmaceutical.
After WHO, 1978a
duplicate portion sampling method (diet/food): Method frequently used for the same purposes as the total diet study technique. Test persons consume their ordinary diet but for each meal, they prepare for subsequent analysis a duplicate portion of all food as prepared, served and consumed.
SN duplicate diet study.
duplicate (replicate) samples (in chemistry): Two (or multiple) samples taken under the same or comparable conditions.
PAC, 1990
dysarthria: Imperfect articulation of speech due to neuromuscular damage.
dysfunction: Abnormal, impaired, or incomplete functioning of an organism, organ, tissue or cell.
dysplasia: Abnormal development of an organ or tissue identified by morphological examination.

dyspnoea: Difficult or laboured breathing.


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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

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