| window level | The CT number setting in Hounsfield units of the midpoint of the window width, which is the gray scale of the image; a typical window level for imaging the lungs if -500; for the abdomen, 0. (05 Mar 2000) |
|---|---|
| hearing level | The measure of the status of hearing as read directly on the hearing loss scale of an audiometer; described in decibels as a deviation from a standard value for zero on the audiometer. (05 Mar 2000) |
| serum iron level | A test that measures the amount of iron (Fe ++) in the blood. The test is performed when iron deficiency is suspected. Normal serum iron is 60 to 170 mcg/dl. Increased levels may be seen in the following: haemochromatosis, haemolysis, haemolytic anaemia, hepatitis, liver necrosis, haemosiderosis, iron poisoning and lead toxicity. Lower than normal levels are seen in chronic GI blood loss, iron deficiency anaemia, insufficient dietary iron, malabsorption, chronic heavy menstrual bleeding, nephrosis and late pregnancy. (27 Sep 1997) |
| sound pressure level | A measure of sound energy relative to 0.0002 dynes/cm2, expressed in decibels. (05 Mar 2000) |
| substrate-level phosphorylation | Synthesis of high-energy phosphate bonds through reaction of inorganic phosphate with an activated (usually) organic substrate. (09 Oct 1997) |
| no-observed-adverse-effect level | The highest dosage administered that does not produce toxic effects. The noael will depend on how closely dosages are spaced (lowest-observed-adverse-effect level and no-observed-effect level) and the number of animals examined. The ultimate objective is usually to determine not the "safe" dosage in laboratory animals but the "safe" dosage for humans. Therefore, the extrapolation most often required of toxicologists is from high-dosage studies in laboratory animals to low doses in humans. (casarett and doull's toxicology: the basic science of poisons, 4th ed) (12 Dec 1998) |
| organic level | The amount of organic matter prescribed to be left after logging. (05 Dec 1998) |
| trophic level | <biology> Stage in a food chain or web leading from primary producers (lowest trophic level) through herbivores to primary and secondary carnivores (consumers- highest level). (09 Oct 1997) |
| lactate level | A test that measures the amount of lactic acid in the blood. Lactic acid is an intermediate product of carbohydrate metabolism and is derived mainly from muscle cells and red blood cells. Exercise will normally raise lactic acid levels. Conditions of oxygen deprivation (for example shock, heart failure, lung disease) will trigger anaerobic metabolism within muscle tissue resulting in lactic acid build up in the tissues. Normal lactic acid levels are 4.5 to 19.8 mg/dl. (27 Sep 1997) |
| lactic acid level | <investigation> A test that measures the amount of lactic acid in the blood. (25 Jun 1999) |
| free calcium level | <biochemistry> The ionised calcium represents the calcium (Ca++) that is the metabolically active calcium. Normal values for ionised calcium in the bloodstream should be 4.4 to 5.3 mg/dl for adults and 4.4 to 6.0 mg/dl for children. Elevations may be seen in hyperparathyroidism, metastatic bone tumour, milk-alkali syndrome, multiple myeloma, Paget's disease, sarcoidosis, PTH-secreting tumours (paraneoplastic syndrome) and vitamin D intoxication. Lower than normal values may be seen in hypoparathyroidism, malabsorption, osteomalacia, pancreatitis, renal failure, rickets and vitamin D deficiency. (27 Sep 1997) |
| level of aspiration | <psychology> The degree or quality of performance (exhibited in a testing situation) which an individual desires to attain or feels he can achieve. (05 Mar 2000) |
| accessory nerve trunk | Part of the accessory nerve formed within the cranial cavity by the union of the cranial and spinal roots, which then divides within the jugular foramen into internal and external branches, the former uniting with the vagus, the latter exiting the foramen as in independent branch which is commonly considered to be the accessory nerve. (05 Mar 2000) |
| bathing trunk nevus | These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma. A biopsy can confirm if cells have turned malignant. Any change in a pre-existing nevus should prompt a physician evaluation. (27 Sep 1997) |
| bifurcation of pulmonary trunk | The division of the pulmonary trunk into right and left pulmonary arteries. Synonym: bifurcatio trunci pulmonalis. (05 Mar 2000) |