Glossary

Last updated on 12 August 2010

acanthosis: thickening of the spinous cell layer of the skin; or, hyperplasia of proliferating cells of stratified squamous mucosa{4111}

ACGIH: American Conference of Governmental Industrial Hygienists

ADR: a slang term meaning "ain't doin' right"

Allele: the sequence variant of a gene, recognized by a DNA assay (polymorphic) or variant phenotype (mutant).

Allograft: graft between genetically dissimilar animals of the same species.{3762}

Altered Schaedler flora: according to the Army which loves this question, it is 8 bacterial species, including 1 spirochete, 4 fusiform, 2 lactobacilli and 1 Bacteroides sp. that are used to colonize germfree rodents.

Alternatives or alternative methods are generally regarded as those that incorporate some aspect of replacement, reduction, or refinement of animal use in pursuit of the minimization of animal pain and distress consistent with the goals of the research. These include methods that use non-animal systems or less sentient animal species to partially or fully replace animals (for example, the use of an in vitro or insect model to replace a mammalian model), methods that reduce the number of animals to the minimum required to obtain scientifically valid data, and methods that refine animal use by lessening or eliminating pain or distress and, thereby, enhancing animal well-being. Potential alternatives that do not allow the attainment of the goals of the research are not, by definition, alternatives. (Animal Care Policy 12)

Anaphylaxis: for a description of how it differs in various species, click here. Think guinea pig...

Asthma: a lower respiratory disease that generally develops after months or years of allergy.{4013} Symptoms include cough, wheeze, and a tight feeling in the chest.

Atopy: an hereditary predisposition for prolonged IgE reactions to environmental allergens{4007}

Autograft: graft from one site to another on the same individual.{3762}

Axenic or germfree rats = those with no flora; born by hysterectomy and reared in germfree barriers{3584}

Backcrossing: breeding back a hybrid to the parent, or breeding homozygotes with heterozygotes{3564}{4162}

Barrier-reared (BR) or defined-flora (DF) = rats reared from conception as gnotobiotes; generally act as breeding stock to produce gnotobiotes{3584}

Bias: non-random (systematic) error in a study that leads to a result distorted from the truth.

Information bias results from problems in ascertainment of the individuals selected for a study, for example, when animals are misclassified with respect to the diseases of interest on the basis of diagnostic test results that are limited in sensitivity and specificity.

Selection bias reflects problems in generating the sample of individuals included for study in a manner that distorts the outcome and the exposure-disease relationship.

Confounding introduces misleading evidence for the role of one or more risk factors in predicting the outcome; some extraneous variable(s) are associated with an important exposure (but not causally following exposure) and are associated with disease in the absence of such exposure. An example is in a study of risk factors for B virus infection in corral-housed groups of NHPs. The housing group confounded the monkey age/antibody relationship, and had to be included in the analysis.{4584}

Bruce effect: introduction of a stange male to a pregnant female's cage at <6 days gestation may cause pre- or post-implantation failure of the pregnancy. This is strain-dependent; if the new male is of a different strain roughly 80% will abort, but if he is of the same strain this is much less. Discovered by Hilda Margaret Bruce.

Coefficient of inbreeding: the probability that two genes at any locus are identical by descent, i.e., that the two genes in one individual originate from one of its ancestors{3564}

Coisogenic strains: Coisogenic strains arise as a result of a mutation in an established inbred strain. The two strains are then absolutely identical except for the affected locus.{3564}

Congenic strain: If a strain of rodent carrying a gene of interest is mated by either repetitive backcrossing or intercrossing with a different strain acting as the background, the resulting strain is congenic with the parent strain that donated the genetic background.{3564} A strain is considered true congenic after 10 backcross or equivalent generations, although mice can be used after 5 generations because they are 95% of the host genome anyway{4184}. There are two types of congenic strains:

Consomic strains: repeated backcrossing of a whole chromosome such as the X or Y onto an inbred strain. See nomenclature for the proper designation.{4184}
Conplastic strains: backcrossing the mitochondrial genome of one strain onto the nuclear genome of another.{4184}

Conventional (CV)=animals which usually maintain an assortment of pathogens as either latent or overt infections{3584}

Dalton's Law: the sum of the partial pressures of each gas in a mixture equals the partial pressure of the mixture, usually barometric pressure. Used in the alveolar gas equation to predict P_aO₂ from measured end-tidal CO₂ and the fraction of oxygen in the inspired gas mixture.

Environmental enrichment: "an independent variable that refers to manipulations to improve the environments of captive primates to enhance psychological well-being."{3563}

Epidemic: a rapid increase in disease frequency occurring in a population beyond some arbitrary background level, or for the first time in an area previously thought to be disease-free.{4584}

Epidemiology: the study of the distribution (person, place, and time) and determinants (risk factors or exposure variables) of disease in populations, with the aim being to reduce morbidity and mortality through development of intervention strategies.{4584}

Gnotobiotic rats = those with more than one known bug; sometimes axenic to begin with and then known microbes are added back{3584}

Hawthorne Effect: happens when the observed values are partly a function of the measurement process; the findings may not be generalizable to the physiologic situation in which there is no instrumentation.{4606}

HEPA filter: high-efficiency particulate air filter that removes 99.97% of particles 0.3µm or larger{4162}

Holandric: inheritance transferred on the Y chromosome{4162}

hyperkeratosis: thickening of the stratum corneum (keratin layer) of the skin{4111}

orthokeratotic hyperkeratosis: cells are anuclear (aka hyperkeratosis)
parakeratotic hyperkeratosis: cells contain nuclei (aka parakeratosis)

hypsodont: teeth that erupt and then continue to grow throughout life

Inbred or isogenic strains are produced by 20 or more successive generations of brother-sister matings, a definition put forth by the Committee on Standardised Genetic Nomenclature for Mice in 1952.{3564} Examples include: CBA, NOD (non-obese diabetic), NOR (non-obese diabetes resistant), AKR, and C57BL mice; and F344 and LEW rats. {3564}

Incidence is the number of cases of disease having their onset during a prescribed period of time. It is often expressed as a rate (for example, the incidence of measles per 1,000 children 5-15 years of age during a specified year). Incidence is a measure of morbidity or other events that occur within a specified period of time. {4584} http://www.cdc.gov/nchs/datawh/nchsdefs/incidence.htm

Intercrossing: breeding two heterozygotes{3564}

LASER: Light Amplification by Stimulated Emission of Radiation

Lee-Boot effect: irregular or suppressed estrus in the absence of males{3987}; female mice housed together isolated from males tend to cease cycling and remain in anestrus or pseudopregnant state{4139}. Described by van der Lee and Boot in 1955.

Minimum Alveolar Concentration (MAC): concentration of anesthetic at which 50% of the animals move in response to noxious stimulus

Neoteny: in some salamanders, larvae reach sexual maturity without metamorphosis{3562}

Neuropathic pain: a type of moderate to severe chronic pain that, unlike acute pain, serves no protective function; it typically occurs after the resolution of a nerve injury{4155}

Northern hybridization: detects RNA (indicating gene expression)

Outbred (random-bred, non-inbred): those having a large degree of genetic variation presumably arising from random matings within the population as a whole. The term "non-inbred" may be preferred. {3564}

parakeratosis: retention of pyknotic nuclei in epithelial cells due to faulty or accelerated cornification{4111}

phytoestrogens: plant compounds that exert estrogenic effects on the central nervous system, induce estrus, and stimulate growth of the genital tract of female animals{4134}

Power: in statistics, refers to 1-b, and is the probability of correctly rejecting a false null hypothesis.

Prevalence is the number of cases of a disease, infected persons, or persons with some other attribute present during a particular interval of time. It is often expressed as a rate (for example, the prevalence of diabetes per 1,000 persons during a year). It is the product of the incidence of disease and its duration.{4584} http://www.cdc.gov/nchs/datawh/nchsdefs/prevalence.htm

Pristane: 2, 6, 10, 14-tetramethylpentadecane, used to prime mice for monoclonal antibody production{4108}

Psychological well-being: "an abstract term that is inferred by measuring behavioral and physiological variables in the affected animals to determine whether a manipulation had the desired effect."{3563}

Recombinant inbred strains: randomly selecting two inbred strains and mating F2 pairs by continuous brother-sister mating. After 20+ generations, these strains should be genetically fixed at more than 98% of the loci that distinguish the two parental strains.{4181}

Segregating inbred strains: Produced by mating F1s by continuous intercrossing and selection, i.e. for the diabetic db mutation. These animals are similar to other inbred strains except that because of the use of brother-sister mating they are more nearly homozygous except for a segment of the chromosome with the gene of interest. If F2s are mated by selecting out pairs of brothers and sisters and then inbreeding, a collection of new strains called recombinant inbred or RI strains will result.{3564}

Sensitivity: true positives/(true positives+false negatives) x100 {4563}; the test's ability to correctly identify those with the disease{4584}

Southern hybridization: detects gene expression (DNA)

Specific pathogen-free (SPF)= animals freed of specific pathogens by the use of gnotobiotic technology (because true gnotobiotes often differed significantly from "normal"){3584}

Specificity: true negatives/(true negatives+false positives) x100{4563}; a test's ability to correctly identify those without the disease{4584}

Stress: the effect of physical, physiologic, or emotional factors (stressors) that induce an alteration in an animal's homeostasis or adaptive state (1993 AVMA Euthanasia Report)

Therapeutic Index: The margin of safety of a drug is the dosage range between that producing a lethal effect in 50% of the population (LD₅₀) and that producing the median effective dose (ED₅₀) in 50% of the population. The ratio of LD₅₀/ED₅₀ is called the therapeutic index.{2725}

Transgenic strains: Transgenic animals have had foreign DNA inserted into the genome, which may subsequently be inherited by their offspring if the germ cells carry the DNA.{3564}

Type I error: rejecting a null hypothesis that is true.

Type II error: accepting (failing to reject) a null hypothesis that is false.

Whitten effect: induction of estrus 72 hours after introduction of a male{3987} (actually from urinary pheromones); a different definition (and a wrong one, as this is the Lee Boot effect) is the suppression of estrus in mice housed in large groups due to pseudopregnancy or diestrus, although pheromones from males can counteract this effect{3551}; occurs to a lesser extent in rats{2764}. Wesley K. Whitten worked at the Jackson lab and this was published in 1956.

Windup (aka central facilitation or central sensitization): a phenomenon of pre-emptive analgesia, in which repeated C-fiber stimulation causes a progressive increase in the responses of interneurons within the dorsal horn of the spinal cord. This has been theorized to work also in the brain, such that nociceptive input primes the brain to respond in augmented fashion to subsequent nociceptive input.{4157}

Xenograft: graft between animals of different species.{3762}

Comments? Send an email to janet.rodgers@vet.ox.ac.uk