++
(sŭb-sīd′ĕns) [L. subsidere, to sink down] The gradual disappearance of symptoms or manifestations of a disease.
++
1. The minimum amount of something essential for life, e.g., a subsistence diet. 2. Any means of barely supporting life.
++
(sŭb″spē′sēz, sŭb″spē′shēz) In taxonomy, a category below a species.
++
(sŭb′stāj) [″ + O.Fr. estage, position] The part of the microscope below the stage by which attachments are held in place.
++
(sŭb′stăns) [L. substantia, being, essence, contents] 1. Material; matter. 2. Substantia. 3. A chemical or drug. 4. When used in a medicolegal context, a chemical with potential for abuse. A great variety of entities are included: alcohol, nicotine, caffeine, sedatives, hypnotics, anxiolytics, and illicit drugs such as cannabis, heroin, or methamphetamines. Almost any substance may be abused even though its clinical use is approved when used as prescribed.
++
anterior perforated s. The portion of the rhinencephalon lying immediately anterior to the optic chiasm. It is perforated by numerous small arteries.
++
chromophilic s. A substance found in the cytoplasm of certain cells that stains similar to chromatin with basic dyes. It includes Nissl bodies of neurons and granules in serozymogenic cells.
++
colloid s. A jelly-like substance in colloid degeneration.
++
ground s. The matrix or intercellular substance in which the cells of an organ or tissue are embedded.
++
high threshold s. A substance such as glucose or sodium chloride present in the blood and excreted by the kidney only when its concentration exceeds a certain level.
++
ketogenic s. A substance that, in its metabolism, gives rise to ketone bodies.
++
low threshold s. A substance such as urea or uric acid that is excreted by the kidney from the blood almost in its entirety. It occurs in the urine in high concentrations.
++
Nissl s. SEE: under Nissl, Franz.
++
posterior perforated s. A triangular area forming the floor of the interpeduncular fossa. It lies immediately posterior to the mammillary bodies and contains numerous openings for blood vessels.
++
pressor s. A substance that elevates arterial blood pressure.
++
reticular s. The skein of threads present in some red blood cells. These are visible only when the cells are appropriately stained.
+++
substance dependence disorder
++
An addictive disorder of compulsive drug use. It is marked by a cluster of behavioral and physiological symptoms that indicate continual use of the substance despite significant related problems. Patients develop a tolerance for the substance and require progressively greater amounts to elicit the effects desired. In addition, patients ...