| breakpoint cluster region | A region on chromosome 22 that is involved in the Philadelphia translocation. Acronym: BCR (15 Nov 1997) |
|---|---|
| gene cluster | A set of closely related genes that code for the same or similar proteins and which are usuallygrouped together on the same chromosome. (09 Oct 1997) |
| cluster analysis | A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both. (12 Dec 1998) |
| cluster headache | <symptom> A term used to describe a headache that is typified by constant, unilateral pain around the eye, with onset usually within 2-3 hours of falling asleep. Can be accompanied by a blocked nasal passage, runny nose, and-or tearing. One may also notice facial flushing, ptosis (dropping eyelid), facial swelling and constriction of the pupils. (27 Sep 1997) |
| cluster of differentiation | Cell membrane molecules that are used to classify leukocytes into subsets. CD molecules are classified by monoclonal antibodies. (05 Mar 2000) |
| cluster of differentiation 2 | A glycoprotein that is expressed on all peripheral T-cells, large granular lymphocytes and most, but not all, thymocytes. CD2 is involved in signal transduction and cell adhesion. (05 Mar 2000) |
| cluster of differentiation 3 | A complex of 5 polypeptides associated with the T-cell receptor and is involved in signal transduction. (05 Mar 2000) |
| cluster of differentiation 4 | A glycoprotein found on various subsets of T-cells, i.e., usually no helper and some T cytotoxic cells. (05 Mar 2000) |
| cluster of differentiation 8 | Membrane glycoprotein found on subsets of T lymphocytes. CD8 is expressed on T cytotoxic cells and T suppressor cells. Acronym: CD (05 Mar 2000) |
| egg cluster | One of the clumps of cells resulting from the breaking up of the gonadal cords in the ovarian cortex; these clumps later develop into primary ovarian follicles. (05 Mar 2000) |
| biological sampling | Denotes sampling that can be taken without jeopardy to the whole organism (e.g., for haematological or biochemical study). Because of the complexity of biological samples it is usually supposed that the source of the sample is thoroughly mixed and hence representative; this assumption is often not true e.g., in genetic studies in mosaic patients. (05 Mar 2000) |
| random sampling | A selection of elements by a formal randomizing device for purposes of inference about a population of inference from that population in such a way that the probability of each possible outcome may be precisely specified in advance; the inferences are necessarily stochastic. (05 Mar 2000) |
| percutaneous umbilical blood sampling | See: PUBS. (12 Dec 1998) |
| chemical sampling | A sample that is obtained by whatever means is convenient and then purified of irrelevant elements before analysis; the assumption of thorough mixing is not necessary. (05 Mar 2000) |
| petrosal sinus sampling | Sampling of blood levels of the adrenocorticotropic hormone (acth) by withdrawal of blood from the inferior petrosal sinus. The inferior petrosal sinus arises from the cavernous sinus and runs to the internal jugular vein. Sampling of blood at this level is a valuable tool in the differential diagnosis of cushing disease, cushing syndrome, and other adrenocortical diseases. (12 Dec 1998) |