Volume 2: Science
Glossary of scientific and other terms

Words in bold refer to other words also defined in this glossary.
Nasopharynx	The part of the pharynx above the soft palate.
Negative-line	A breed or selection line of an animal species which is known to be resistant to particular strains of disease agent. Cf. positive-line.
Nematode	Phylum of elongated cylindrical worms parasitic in animals or plants or free-living in soil or water.
Nemavirus	Proposed nature of the infective agent of TSEs, in which TSE-associated single-stranded DNA (ss-DNA) is sandwiched between a core of SAF protein and an outer layer of protein. See paragraphs 2.59-61.
Neonate	Newborn.
Neuroblastoma	A malignant haemorrhagic tumour.
Neurodegenerative disease	A disorder of the central nervous system characterised by gradual and progressive loss of nervous tissue.
Neurology	The scientific study of the nervous system especially in respect to its structure, functions, and abnormalities.
Neuron	Nerve cell.
Neuropathology	The study of diseases of the nervous system and the structural and functional changes occurring in them. (Taber)
Neurotransmitter	A substance which transmits the action of a nerve to another cell.
NHS	National Health Service.
NPU	Neuropathogenesis Unit, Edinburgh.
NSE (neuron specific enolase)	Specific enzyme involved in the metabolism of carbohydrates (enolase), found only in nerve cells.
Nucleic acid	Substance constructed out of units known as nucleotides. Two types of nucleic acid occur in nature: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). (BMD)
Nucleotide	Basic structural unit of nucleic acids (RNA and DNA), consisting of a sugar joined to any of five purine or pyrimidine bases (cytosine, guanine, adenine, thymine, and uracil) and to a phosphate group.
Nyala	A deer-like African ruminant. Cf. gemsbok, eland.
Ocelot	A medium-sized American wildcat (Felis pardalis).
Octapeptide	A protein fragment or molecule that consists of eight amino acids.
Oestrus	The period in which a cow is receptive to a male.
Offal	Internal organs and entrails of animals.
OP	Organophosphate or organophosphorous insecticide: any of several synthetic chemical insecticides, based on chemical compounds including phosphate, which affect the nervous system. (DOA)
Organelle	A specialised part of a cell that performs a distinctive function. (Taber)
Oropharynx	The central portion of the pharynx.
Oryx	Small genus of large, heavily-built African and Arabian antelopes.
OST	Office of Science and Technology.
Ovine	Of, or relating to, sheep.
Parenteral	Inoculation by any route other than by the mouth or by the bowel. (BMD)
Parkinson's disease	A chronic progressive nervous disease chiefly of later life that is linked to decreased dopamine production in the brain and is marked by tremor and weakness of resting muscles and by a shuffling gait.
Parturition	The action of giving birth to young; childbirth. (COD)
Passage	The replication of a micro-organism in culture, in a living organism or in a developing egg. In the case of TSEs, the infectious agent is often 'passaged' through successive experimental animals.
Pathogen	A bacterium, virus or other micro-organism that can cause disease. (COD)
Pathogenesis	The manner of development of a disease. (COD)
Pathology	The study of the causes of, and changes produced in the body by, disease. (BMD)
Pattern of disease	The physical characteristics (both visible and invisible) of any particular disease.
Pedigree	The line of descent of a purebred animal.
Peptide	A compound consisting of two or more amino acids linked in sequence. (COD) Proteins are polypeptides.
Peripheral	By any route other than via the central nervous system.
PES	Public Expenditure Survey.
Peyer's patches	An aggregation of lymph nodules on the small intestine. They appear as raised oval areas in mucous tissue, ie, tissues of the membranes which line the intestinal tract, and the submucosal areas, ie, the areas below the mucous membrane.
Pharmacological	The properties and reactions of drugs especially with relation to their therapeutic value.
Pharynx	The part of the vertebrate alimentary canal between the cavity of the mouth and the oesophagus (gullet).
Phenol	A corrosive poisonous crystalline derivative of benzene, used as antiseptic and disinfectant and in the manufacture of pharmaceuticals.
Phenotype	The physical characteristics (both visible and invisible) of any particular individual (or disease).
PHLS	Public Health Laboratory Service.
Phosmet	An OP insecticide used since 1985, poured on the back of an animal. Used on plants as well as animals. Also found in combination with other insecticides such as carbophenothion.
Physiological	Characteristic of, or appropriate to an organism's healthy or normal functioning.
Pituitary gland	An ovoid structure, weighing around 0.5 grams in the adult human, attached to the base of the brain, and lying in the depression in the base of the skull - the most important ductless, or endocrine, gland in the body. (BMD). It produces various internal secretions directly or indirectly impinging on most basic body functions. See also hGH.
Point mutation	A mutation during DNA synthesis that can occur when the wrong base is incorporated into the new DNA strand.
Polyanionic glycan	A complex carbohydrate (polysaccharide) bearing multiple negative charges.
Polymorphism	The occurrence in a population of two or more genetically determined variant forms of a particular characteristic at a frequency where the rarest could not be maintained by recurrent mutation alone. A genetic locus is considered to be polymorphic if the variant form is found in more than 1 per cent of the population.
Polypeptide	A chain of peptides.
Polysaccharide	Linear or branched polymers of simple sugars (monosaccharides). Polysaccharides are often linked to proteins in glycoproteins and confer specific properties to the structure and function of the glycoprotein.
Porcine	Of, or characteristic of, pigs.
Positive-line	A breed or selection line of an animal species which is known to be susceptible to particular strains of a disease agent. Cf. negative-line.
Post-mortem	An examination of a dead body to determine the cause of death; literally, 'after death'.
Post-partum	After birth.
Post-translational event	The modification of a protein after its synthesis (translation from mRNA), such as glycosylation or phosphorylation.
Primate	Any of an order of mammals (Primates) comprising humans, apes, monkeys, and related forms (as lemurs and tarsiers).
Prion	See prion protein. The word 'prion' was coined in the 1980s by a rearrangement of elements from proteinaceous infectious particle.
Prion protein (PrP)	Protease-resistant membrane protein, also known as prion protein (PrP): a normal, host-coded protein that becomes protease-resistant in infected tissue and accumulates around CNS lesions in TSEs. The protease-resistant form PrPSc is a major component of SAFs. Until recently the function of PrP was unknown despite its presence in many different organs and tissues of healthy animals, including the brain. There is evidence that PrP in uninfected animals has the property of mopping up harmful 'oxygen free radicals', or that it carries out some signalling functions between cells.
PRNP	Human PrP gene located on chromosome 20.
Progesterone	A hormone that stimulates the uterus to prepare for pregnancy.
Prostaglandins	Compounds with hormone-like effects, such as promoting uterine contractions.
Protease	Enzyme that catalyses the splitting of the bonds linking amino acids in a protein.
Protein	A folded chain of amino acids.
Proteinase K	A type of protease.
Protein markers	Proteins of known characteristics (eg, weight, glycosylation, etc) that can be used as a standard, or marker, against which unknown proteins can be compared.
Proteolysis	The splitting of proteins by proteases.
Proteolytic cleavage	The cleavage of proteins between specific amino acid residues to yield distinctive peptide fragments. Proteolytic cleavage can be carried out by both enzymes and other chemicals.
PrPc, PrPSen	PrPCellular: the normal cellular isoform of PrP, also known as PrPSen (for 'sensitive to protease').
PrP gene	Gene found in mammals from which the amino acid sequence of PrPC is determined.
PrPSc, PrPRes	PrPScrapie: the abnormal disease-specific isoform of PrP derived post-translationally from PrPC. Also known as PrPResistant PrPSc is a generic term now used for all disease-associated PrP.
Pruritis	Itching.
R&D	Research and development.
Recessive	Of diseases which occur only when both chromosomes of a homologous pair carry a particular mutant gene.
Reduction	The process whereby electrons are added to an atom during a chemical reaction. For example, the reduction of a disulphide bond results in the breaking of that bond.
Render (rendering process)	Processing offal and other parts of discarded animal carcasses to make meat and bone meal, and tallow. This is achieved by drying/cooking and separating the solid fraction (protein meals) from the melted liquid fraction (tallow and animal fat). See continuous and batch rendering.
Retropharyngeal	Of the posterior portion of the pharynx.
RFB	Ruminant feed ban.
Rida	A TSE of sheep in Iceland. Equivalent to scrapie.
RNA	Ribonucleic acid. See nucleic acid.
Rumen	The first compartment of the stomach of a ruminant. (DOA)
Ruminant	Animal that chews the cud (partly digested food) regurgitated from its rumen, and has a stomach of four compartments.
S&T	Science and technology.
SAFs	Scrapie-associated fibrils. Abnormal fibrils which can be detected in infected-brain extracts with an electron microscope. The presence of these fibrils is now recognised as one characteristic of TSEs.
Saline	A salt solution.
SBO	Specified Bovine Offal.
Scarification	Shallow incisions in the skin.
Sciatic nerve	Either of the pair of largest nerves in the body that arise one on each side from the nerve plexus supplying the posterior limb and pelvic region and that pass out of the pelvis and down the back of the thigh.
Scrapie	A transmissible spongiform encephalopathy endemic in British sheep and found in many parts of the world. Also found in goats. Can be transmitted naturally or experimentally to other animals such as mice. The experimental model for work on TSEs.
SE	Spongiform encephalopathy.
SEAC	Spongiform Encephalopathy Advisory Committee.
Seizures	A sudden manifestation or recurrence of a disease.
Serum	The clear liquid that separates from blood when clotting occurs.
SHHD	Scottish Home and Health Department.
Sinc gene	Mouse gene that regulates the incubation period of natural and experimental scrapie and other TSE agents. Its gene product (PrP) is postulated as the agent replication site in the virino hypothesis or as the precursor of infectious proteins in the prion theory.
Sip gene	Sheep gene that regulates the incubation period of natural and experimental scrapie: the version of the sinc gene in sheep (see above).
Sodium metaperiodate	A powerful oxidising chemical used for disinfection.
Somatic cell	A cell which is not a 'germ cell' (gamete).
SPECT	Single photon emission computed tomography. A neuroimaging technique which shows cross section images of the brain. Unlike MRI, which depicts anatomy, SPECT scanning provides information on brain function.
Spinal cord	Part of the central nervous system that lies protected by the vertebrae, and from which spinal nerves emerge.
Spinocerebellar	Of the spinal cord and cerebellum.
Spleen	An organ of the lymphoreticular system (LRS). Major site of replication of TSEs in some species.
Splenectomy	Surgical removal of the spleen.
Spongiform encephalopathy (SE)	See TSE.
Sporadic disease	Occurring in single cases here and there, as distinct from an epidemic.
ss-DNA	Single-stranded DNA, ie, not in the form of a double helix, proposed to be part of the nemavirus particle.
Stereotactic electrodes	Electrodes used in neurosurgery to stimulate specific areas of the brain. The electrodes are mounted on apparatus that allow precise positioning.
Straight feedstuff ('straights')	A vegetable or animal product in its natural state, fresh or preserved, and any single product derived from the industrial processing thereof, and any single organic or inorganic substance, whether or not it contains any additive, intended as such for oral animal feeding.
Strains	Micro-organisms identical in antigenicity or other features which distinguish them from other related organisms. With TSEs antigenicity is not relevant. For example, scrapie strains can be distinguished by relative lengths of incubation in specific PrP genotypes and/or the type and pattern of lesions in affected brains.
Strain-typing	The identification of, in this case, different TSEs by ascertaining the length of incubation period and the pattern of disease in the experimental host.
Subacute	Of a disease, between acute and chronic.
Subclinical (as subclinical state)	When a disease has not progressed far enough to show clear signs and symptoms.
Subcutaneous (s.c.) injection	Injection under the skin.
Submaxillary salivary gland	Salivary gland located deep behind the jaw bone.
Substrate	A substance acted upon, for example by an enzyme.
Suspension	The state of a solid when its particles are mixed with, but not dissolved in, a fluid or another solid. (Taber)
Sympathetic nerve	A part of the autonomic nervous system which is concerned mainly with the movements and other functions of the internal organs, secretory glands and blood vessels, the activities of which proceed independently of the will.
Systemic	Affecting the body generally.
Tallow	A product of the rendering process. It usually refers to the fat produced by rendering and covers the whole range of different products from human food to animal feed and technical greases or, after processing by the soap and oleochemical industries, products as diverse as cosmetics and pharmaceuticals, paints and car tyres.
Tau protein	Proteins which stabilise elements of the cell's structure. Tau protein has been used as a marker for BSE infection.
Thorax	Chest (hence thoracic).
Thymus gland	A lymphoid organ situated towards the front of the chest area, the thymus produces a class of white blood cells, known as T-cells, for the immune response. An SBO. Also known as sweetbread in ruminants.
Titration	A process used in chemistry to ascertain the amount of a substance in a solution by measuring the volume of a standard reagent required to react with it.
Titre	A measure of concentration of a substance. In this Report, an estimate of the concentration of a TSE agent in a tissue or tissue sub-fraction.
TME	Transmissible mink encephalopathy, ie, a TSE in mink.
Toxicity	The quality of being poisonous, especially the degree of adverse affects. The severity of toxicity produced by any chemical is directly proportional to the exposure concentration and the exposure time. This relationship varies with the developmental stage of an organism and with its physiological status.Acute toxicity: adverse effects occurring within a short time of administration of a single dose of a chemical, or immediately following short or continuous exposure, or multiple doses over 48 hours or less.Subacute (subchronic) toxicity: adverse effects occurring as a result of repeated daily dosing of a chemical, or exposure to the chemical, for part of an organism's lifespan (usually not exceeding 10 per cent). With experimental animals, the period of exposure may range from a few days to six months. Chronic toxicity: adverse effects occurring as a result of repeated daily dosing of a chemical, or exposure to the chemical, for part of an organism's lifespan (usually not exceeding 19 per cent). With experimental animals, this usually means a period of exposure of more than three months. (IPCS)
Tracheal	Relating to the trachea, the windpipe.
Transgenic	Genetically engineered animals, bred by a technique in which whole genes or parts of genes from one animal are inserted experimentally into the genes of the embryos of another. For example, mice can be given the PrP gene from hamsters.
Transmission	The passage of infectious micro-organisms from one animal to another.
Trigeminal ganglia	A cluster of neurons which supply motor and sensory function to the face.
TSE	Transmissible spongiform encephalopathy. Disease of the neurological system. Spongy degeneration of the brain with progressive dementia. Examples in humans include CJD and kuru. Among animals: scrapie, CWD, TME and BSE. (BMD)
TSE isolate	The experimental outcome of primary experimental transmission of a naturally occurring TSE to another animal species, where the strain or strains involved in the experimental infection remain to be identified. This first passage of experimental material may then be further passaged in a series and lead to the identification of the strain(s) involved.
Tubulofilament	Term used to describe the structure of the putative nemavirus particle.
UKASTA	UK Agricultural Supply Trade Association.
Ungulate	Any hoofed animal.
Uric acid	A crystalline, sparingly soluble substance found in blood and urine.
Vaccination	Treatment with an antigenic preparation used to stimulate the production of antibodies and provide immunity against a disease.
Vacuole/vacuolation	A vacuole is any space or cavity found within or between cells in any type of tissue. In TSEs several types of intra-cellular vacuoles can be present in the brain. Vacuolation is thus the development of characteristic vacuoles in the brain. Assessment of the locations, severity and types of vacuolation is used in distinguishing different TSE strains.
Vagus nerve	Either of the 10th pair of cranial nerves that arise from the medulla and supply chiefly the viscera especially with autonomic sensory and motor fibres.
Valine	An essential amino acid. See also methionine.
Variant CJD (vCJD)	New variant CJD. Identified in 1996 as a previously unrecognised form of CJD, having a novel pathology and consistent disease pattern. Exposure to BSE is the most likely explanation for the emergence of the disease. It is now known as vCJD (variant CJD).
Vegetative dysfunction	The abnormal functioning of the autonomic nervous system which acts in an involuntary manner, to a large extent independently of the brain and spinal cord.
Vertical transmission	From parent to offspring. Cf. lateral transmission.
VICs	Veterinary Investigation Centres.
VIDA	Veterinary Investigation Diagnostic Analysis.
Virino	A hybrid between a protective host protein (PrP) and a replicable informational molecule, independent of the host, that is either an untranslated nucleic acid or a novel analogue.
Virus	Viruses are obligate intracellular parasites consisting of DNA or RNA enclosed in a protein coat. They range in diameter from 20 to 300 nanometres (a nanometre is one thousand millionth of a metre).
VLA	Veterinary Laboratories Agency.
Weanling	A young animal whose mother's milk has recently been replaced by some other form of nourishment.
Western blot	See immunoblot. The western blot method is used specifically for proteins.