| metachromatic | Denoting cells or dyes that exhibit metachromasia. Synonym: metachromophil, metachromophile. (05 Mar 2000) |
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| metachromatic bodies | Concentrated deposits consisting primarily of polymetaphosphate and occurring in many bacteria as well as in algae, fungi, and protozoa; m. Body's differ in staining properties from the surrounding protoplasm. See: metachromasia. (05 Mar 2000) |
| metachromatic granules | Granule's that stain a colour different from that of the dye used. See: metachromasia. Term sometimes used as a synonym for volutin. (05 Mar 2000) |
| metachromatic leukodystrophy | <radiology> Dysmyelinating disease, autosomal recessive, aryl sulfatase A -- absent from urine and serum, most present by 2 yrs, die at 3-4 yrs, may arise at any age, CT: decreased density of white matter, primarily in centrum semiovale, with or without focal gall bladder defects (!) (12 Dec 1998) |
| metachromatic stain | <technique> A stain, such as methylene blue, thionin, or azure A, that has the ability to produce different colours with various histological or cytological structures. (05 Mar 2000) |
| leukodystrophy, metachromatic | A sphingolipidosis where there is defective desulfation of galactosyl-3-sulfate ceramide due to a defective enzyme cerebroside sulfatase (arylsulfatase a). The result is an accumulation of sulfatide in neural and non-neural tissues which manifests as mental deterioration and severe disturbances of the central nervous system. (12 Dec 1998) |
| alpha substance | A filamentous plasmatic material, beaded with granules, demonstrable by means of vital staining in the immature red blood cells. Synonym: alpha substance, filar mass, filar substance, substantia reticularis, substantia reticulofilamentosa. Synonym: reticular formation. (05 Mar 2000) |
| anterior perforated substance | A region at the base of the brain through which numerous small branches of the anterior and middle cerebral arteries (lenticulostriate arteries) enter the depth of the cerebral hemisphere; it is bordered medially by the optic chasm and anterior half of the optic tract, rostrally and laterally by the lateral olfactory stria; its anteromedial part corresponds to the olfactory tubercle. Synonym: substantia perforata anterior, locus perforatus anticus, olfactory area. (05 Mar 2000) |
| autacoid substance | A substance formed metabolically by one set of cells, which alters the function of other cells. (This term is sometimes used in place of the term hormone.) (05 Mar 2000) |
| bacteriotropic substance | Opsonin or other substance that alters bacterial cells in such a manner that they are more susceptible to phagocytic action. (05 Mar 2000) |
| basophilic substance | The material consisting of granular endoplasmic reticulum and ribosomes that occurs in nerve cell bodies and dendrites. Synonym: basophil substance, basophilic substance, chromophil substance, Nissl bodies, Nissl granules, substantia basophilia, tigroid bodies, tigroid substance. (05 Mar 2000) |
| basophil substance | The material consisting of granular endoplasmic reticulum and ribosomes that occurs in nerve cell bodies and dendrites. Synonym: basophil substance, basophilic substance, chromophil substance, Nissl bodies, Nissl granules, substantia basophilia, tigroid bodies, tigroid substance. (05 Mar 2000) |
| blood group substance | Blood group-specific substances A and B, solution of complexes of polysaccharides and amino acids that reduces the titre of anti-A and anti-B isoagglutinins in serum from group O persons; used to render group O blood reasonably safe for transfusion into persons of group A, B, or AB, but does not affect any incompatibility that results from various other factors, such as Rh. (05 Mar 2000) |
| vasodepressor substance | An incompletely characterised chemical, apparently produced during liver damage, that tends to decrease vascular pressures and relax arterial walls. (05 Mar 2000) |
| gelatinous substance | The apical part of the posterior horn (dorsal horn; posterior gray column) of the spinal cord's gray matter, composed largely of very small nerve cells; its gelatinous appearance is due to its very low content of myelinated nerve fibres. Synonym: substantia gelatinosa, Rolando's gelatinous substance, Rolando's substance. (05 Mar 2000) |