| killer cells, lymphokine-activated | Cytolytic lymphocytes with the unique capacity of killing natural killer (nk)-resistant fresh tumour cells. They are interleukin-2-activated nk cells that have no MHC (major histocompatibility complex) restriction or need for antigen stimulation. Lak cells are used for adoptive immunotherapy in cancer patients. (12 Dec 1998) |
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| fluorescence-activated cell sorter | <technique> Flow cytometry is an emerging technique which holds great promise for the separation, classification and quantitation of blood cells and antibodies which affect blood cells. Complex computerised instruments are used to pass a monocellular stream of cells, platelets or other microscopic particulate elements through a beam of laser light. The cells are categorised first by size and then computer analysed to sort the mixture of cellular elements into cell type by size. Cells are labelled with fluorescent dye and then passed, in suspending medium, through a narrow dropping nozzle so that each cell is in a small droplet. A laser based detector system is used to excite fluorescence and droplets with positively fluorescent cells are given an electric charge. Charged and uncharged droplets are separated as they fall between charged plates and so collect in different tubes. The machine can be used either as an analytical tool, counting the number of labelled cells in a population or to separate the cells for subsequent growth of the selected population. Further sophistication can be built into the system by using a second laser system at right angles to the first to look at a second fluorescent label or to gauge cell size on the basis of light scatter. The great strength of the system is that it looks at large numbers of individual cells and makes possible the separation of populations with, for example: particular surface properties. Tabulation of counted data in conjunction with size analysis enables determination of relative percentages of each specific cellular subset for which monoclonal antibody conjugates are utilised, even when the size of the cell is identical to other subset species. Flow cytometry is a slightly imprecise but common term for the use of the Fluorescence-activated Cell Sorter (FACS). (01 Dec 1998) |
| fluorescence-activated cell sorting | <technique> A technique for separating and sorting cells marked with a fluorescent label based on how much they fluoresce at a particular wavelength. (12 Jan 1998) |
| light-activated resin | A resin which uses visible or ultraviolet light to excite a photoinitiator which interacts with an amine to form free radicals and initiate polymerization. Used mainly in restorative dentistry. Synonym: light-activated resin. (05 Mar 2000) |
| absent state | The saemiconscious state associated with an epileptic attack. Synonym: absent state. (05 Mar 2000) |
| acute confusional state | <psychiatry> A condition of severe confusion or rapid change in brain function. This often occurs as the result of a mental illness or physical illness. Symptoms include lethargy, agitation, confusion, disorientation and delirium. (27 Sep 1997) |
| anxiety tension state | A milder form of an anxiety disorder. See: anxiety disorders. (05 Mar 2000) |
| apallic state | Diffuse, bilateral cerebral cortical degeneration caused by head injury, anoxia, or encephalitis, a state of persistent unresponsiveness, such as akinetic mutism, caused by brain damage. See: vegetative. Synonym: apallic syndrome, apallic. (05 Mar 2000) |
| carrier state | A condition in which a human who is not himself sick harbors an infective organism which may cause disease in those to whom it is transmitted. (12 Dec 1998) |
| refractory state | Subnormal excitability immediately following a response to previous excitation; the state is divided into absolute and relative phases. (05 Mar 2000) |
| central excitatory state | The building up of excitatory influences produced by individual impulses finally causes firing of the next neuron. (05 Mar 2000) |
| perfect state | In fungi, that portion of the life cycle in which spores are formed after nuclear fusion. (05 Mar 2000) |
| mental state | <clinical sign, psychiatry> A finding on physical examination that may refer to any number of abnormal changes in baseline mental functioning. Milder examples include mood changes, irritability, personality changes, depression or blunted affect. Advanced changes include confusion, lethargy, sleepiness, hallucinations, unresponsiveness and coma. (27 Sep 1997) |
| ground state | <chemistry, radiobiology> The state of a nucleus, atom or molecule at its lowest energy. All other states are excited. (16 Dec 1997) |
| persistent vegetative state | A persistent loss of upper cortical function that may follow acute (e.g., infections, toxins, trauma or vascular) events or chronic (e.g., degenerative) events. The patient is bedridden and nutritional support is completely passive, either parenteral or via nasogastric tube. The patient does not require respiratory support or circulatory assistance for survival and is in a state of chronic wakefulness without awareness which may be accompanied by spontaneous eye opening, grunts or screams, brief smiles, sporadic movement of facial muscles and limbs. While the eyes blink upon stimulation, they do not do so in response to visual threats. Some patients chew or clamp their teeth. Urinary and faecal incontinence is universal. (12 Dec 1998) |