| PAG | Peri-Aqueductal Gray |
|---|---|
| GPS | Goodpasture syndrome; gray platelet syndrome; guinea pig serum; guinea pig spleen |
| gr | grade; graft; grain; gram; gravity; gray; gross |
| Gy | gray |
| DM | defined medium; dermatomyositis; Descemet's membrane; dextromaltose; dextromethorphan; diabetes mell... |
| white-matter disease | <radiology> Demyelinating (myelinoclastic), destruction of existing myelin, acquired diseases with inflammatory characteristics, includes: MS, PML, encephalomyelitis, also may be due to anoxia, infarct, tumour, radiation dysmyelinating, abnormal myelin formation or maintenance, two groups: primary white-matter diseases: leukodystrophies, involve gray matter: Niemann-Pick, Gaucher, Tay-Sachs (12 Dec 1998) |
|---|---|
| sclerosis of white matter | <radiology> Type of dysmyelinating disease, hereditary, peripheral nervous system unaffected in some disorders Specific diseases: adrenoleukodystrophy, metachromatic leukodystrophy, spongy degeneration (Canavan), globoid cell (Krabbe) leukodystrophy, Alexander disease, Pelizaeus-Merzbacher disease, Cockayne syndrome (12 Dec 1998) |
| anterior gray column | The central gray matter of the spinal cord surrounding the central canal. Synonym: substantia intermedia centralis et lateralis, anterior gray column, Stilling's gelatinous substance, substantia gelatinosa centralis. (05 Mar 2000) |
| central gray substance | In general: the predominantly small-celled gray matter adjoining or surrounding the central canal of the spinal cord and the third and fourth ventricles of the brainstem, in particular: the thick sleeve of gray matter surrounding the cerebral sylvian aqueduct in the midbrain, rostrally continuous with the posterior nucleus of the hypothalamus; in sections stained for myelin it stands out from the adjoining tectum and tegmentum by the poverty of its myelinated fibres. Synonym: substantia grisea centralis. (05 Mar 2000) |
| periaqueductal gray | Central gray matter surrounding the cerebral aqueduct in the mesencephalon. Physiologically it is probably involved in rage reactions, the lordosis reflex, feeding responses, bladder tonus, and pain. (12 Dec 1998) |
| Gray | <radiobiology, unit> The new international system unit (SI unit) of absorbed dose of radiation (Gy), 1 Gy = 1 J kg-1 = 100 rad. (16 Dec 1997) |
| gray cataract | A cataract of gray colour, usually seen in senile, mature, or cortical cataract. (05 Mar 2000) |
| gray collie syndrome | An autosomal recessive, inherited immunodeficiency of gray collie dogs characterised by overwhelming recurrent bacterial infections, bleeding, and coat colour dilution. Synonym: gray collie syndrome. (05 Mar 2000) |
| gray columns | The three somewhat ridge-shaped masses of gray matter (anterior, posterior, and lateral columns) that extend longitudinally through the centre of each lateral half of the spinal cord; in transverse sections these columns appear as gray horns and are therefore commonly called ventral or anterior, dorsal or posterior, and lateral horn, respectively. Synonym: columnae griseae. (05 Mar 2000) |
| gray degeneration | Degeneration of the white substance of the spinal cord, the fibres of which lose their myelin sheaths and become darker in colour. (05 Mar 2000) |
| gray fibres | A fibre having no myelin covering (CNS); a naked axon; in the PNS represented by all axons lying in troughs in a single Schwann cell (Schwann cell unit); a slow conducting fibre. Synonym: gray fibres, nonmedullated fibres, Remak's fibres. (05 Mar 2000) |
| gray hepatisation | The second stage of hepatisation in pneumonia, when the exudate is beginning to degenerate prior to breaking down; the colour is a yellowish gray or mottled. (05 Mar 2000) |
| gray induration | A condition occurring in lungs during and after pneumonic processes in which there is failure of resolution; there is a conspicuous increase in fibrous connective tissue in the walls of the alveoli, and also within the alveoli (e.g., fibrous organization of exudate); in contrast to brown induration, there is usually not a prominent degree of pigmentation, unless chronic passive congestion is also present. (05 Mar 2000) |
| gray infiltration | A term sometimes used for the relatively rapidly formed, semisolid, gray or gray-white exudate (chiefly necrotic cells and remnants of tissue, and macrophages) resulting from unusually acute, overwhelming, diffuse tuberculous infection in the lung. Synonym: gelatinous infiltration. (05 Mar 2000) |
| gray layer of superior colliculus | Term applied to any one of the three major layers of gray matter of the superior colliculus that alternate with layers composed chiefly of nerve fibres: 1) the superficial gray layer of superior colliculus, above the largely white layer of the incoming fibres of the optic tract (optic layer); 2) the middle gray layer of superior colliculus, placed between the optic layer and a more deeply located layer of fibres, the stratum lemnisci; 3) the deep gray layer of superior colliculus, between the stratum lemnisci and the central gray substance surrounding the cerebral aqueduct, and containing the large nerve cells from which most of the colliculus descending connections (tectobulbar, tectopontine, and tectospinal tract) originate. Synonym: stratum griseum colliculi superioris, stratum cinereum colliculi superioris. (05 Mar 2000) |