| phosphatase unit | See: Bodansky unit, King unit. (05 Mar 2000) |
|---|---|
| photosynthetic unit | <biochemistry, plant biology> Group of photosynthetic pigment molecules (chlorophylls and carotenoids) that supply light to one reaction centre in photosystem I or II. (18 Nov 1997) |
| physiologic unit | The ultimate (hypothetical) vital unit of protoplasm, as conceived by Spencer, the smallest division of an organ that will perform its function; e.g., the uriniferous tubule. (05 Mar 2000) |
| colony-forming unit | <cell biology> An individual cell which is able to clone itself into an entire colony of identical cells. Irradiated mice can have their immune systems reconstituted by the injection of bone marrow cells from a nonirradiated animal. The injected cells form colonies in the spleen (hence s), each colony representing the progeny of a pluripotent stem cell. Operationally, therefore, the number of colony-forming units is a measure of the number of stem cells. Acronym: CFU (09 Oct 1997) |
| motor unit | A single somatic motor neuron and the group of muscle fibres innervated by it. (05 Mar 2000) |
| complement unit | The smallest amount (highest dilution) of complement that will cause haemolysis of a unit of red blood cells in the presence of a haemolysin unit. Synonym: alexin unit. (05 Mar 2000) |
| plaque-forming unit | <virology> Number of infectious virus particles or Ig producing cells per unit volume. See: plaque assay. <microbiology> Refers to any entity which can give rise to a plaque. For example: if a phage stock solution has 1010 pfu/ml, it means that every ml of this stock has 1010 phage particles which can form plaques. This (pfu/ml) is the conventional way to refer the concentration of a phage preparation. Compare: CFU. (10 Oct 1997) |
| mouse unit | The quantity of oestrogen capable of producing in a spayed mouse a characteristic change in the vaginal epithelium, namely, disappearance of leukocytes and appearance of cornified cells, as determined by a vaginal smear; equal approximately to one-half of an estrone unit. Synonym: mouse unit. (05 Mar 2000) |
| Corner-Allen unit | A unit of progestational activity, measured in rabbits; the minimum dose which, divided into five equal daily portions, produces on the sixth day the uterine changes characteristic of the eighth day of normal pregnancy; the unit has about the same potency as the international unit. (05 Mar 2000) |
| corpus luteum hormone unit | The progestational activity of 1 mg of unit of progestational activity; standard preparation of pure progesterone. See: Clauberg test, Corner-Allen unit. Synonym: corpus luteum hormone unit, unit of luteinizing activity. (05 Mar 2000) |
| CT unit | A unit of X-ray attenuation in each picture element of the CT image. See: Hounsfield unit. (05 Mar 2000) |
| haemolytic unit | The smallest quantity (highest dilution) of inactivated immune serum (haemolysin) that will sensitise the standard suspension of erythrocytes so that the standard complement will cause complete haemolysis. Synonym: amboceptor unit. (05 Mar 2000) |
| Haldane's evolutionary unit | <unit> A unit of measurement, given in darwins, which measures the increase in body size of a chronospecies over evolutionary time. (13 Nov 1997) |
| progesterone unit | The progestational activity of 1 mg of unit of progestational activity; standard preparation of pure progesterone. See: Clauberg test, Corner-Allen unit. Synonym: corpus luteum hormone unit, unit of luteinizing activity. (05 Mar 2000) |
| prolactin unit | The specific lactogenic activity contained in 0.1 mg of the standard preparation of the lactogenic substance of the anterior pituitary gland. (05 Mar 2000) |