| MPC | marine protein concentrate; maximum permissible concentration; mean plasma concentration; meperidine... |
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| MPCUR | maximum permissible concentration of unidentified radionucleotides |
| MPD | main pancreatic duct; maximum permissible dose; mean population doubling; membrane potential differe... |
| NEDEL | no epidemiologically detectable exposure level |
| REL | rate of energy loss; recommended exposure limit; resting expiratory level |
| inhalation exposure | The exposure to potentially harmful chemical, physical, or biological agents by inhaling them. (12 Dec 1998) |
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| occupational exposure | The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation. (12 Dec 1998) |
| environmental exposure | The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals. (12 Dec 1998) |
| exposure | <radiobiology> A quantitative measure of x or gamma radiation at a certain place, based on its ability to produce ionisation in air. The former special unit of exposure was the roentgen (R). 1R = 2.58 x 10-4 C/kg. In the international system (SI unit), the special unit is coulomb per kilogram. (Exposure also is frequently used as a synonym for irradiation). (16 Dec 1997) |
| exposure dose | The radiation dose, expressed in roentgens, delivered at a point in free air. Synonym: air dose. (05 Mar 2000) |
| exposure keratitis | Inflammation of the cornea resulting from irritation caused by inability to close the eyelids. Synonym: lagophthalmic keratitis. (05 Mar 2000) |
| exposure odds ratio | <epidemiology> See Odds ratio. (05 Dec 1998) |
| ACE level | <investigation> This is a blood test which measures the concentration of angiotensin-converting enzyme (ACE) in the bloodstream. Elevations in angiotensin-converting enzyme are seen sarcoidosis, histoplasmosis, alcoholic cirrhosis, asbestosis, berylliosis, diabetes, Hodgkin's disease, hyperthyroidism, amyloidosis, primary biliary cirrhosis, idiopathic pulmonary fibrosis, pulmonary embolism, scleroderma, silicosis, tuberculosis, Gaucher's disease and leprosy. The normal values are 18 to 67 U/ml over 20 years of age (people under 20 have higher levels). (15 Jan 1998) |
| acoustic reference level | The biological reference level for sound measurements. When the term decibel is used to indicate the noise level, a reference quantity is implied; this reference value is usually expressed as a sound pressure of 20 micronewtons per square meter. The reference level is referred to as 0 decibels, the baseline of the scale of noise level's; this baseline is considered the weakest sound that can be heard by a person with very good hearing in an extremely quiet location. Other equivalent reference level's still being used include 0.0002 microbar and 0.0002 dyne per square centimeter. (05 Mar 2000) |
| background level | The average amount of a substance present in the environment. Originally referring to naturally occurring phenomena. Used in toxic substance monitoring. (05 Dec 1998) |
| blood porphyrin level | A test which is used to measure red blood cell porphyrin levels. Porphyrins are pigments found in both animal and plant life. This test is useful in evaluating any number of porphyrin disorders (involving the various porphyrins) of red blood cells. Increased levels of coproporphyrins can indicate congenital erythropoietic porphyria or sideroblastic anaemia. Increased protoporphyrins may be seen in infection, thalassaemia, sideroblastic anaemia, iron deficient anaemia, increased erythropoiesis and lead poisoning. Increased uroporphyrins may indicate congenital erythropoietic porphyria or erythropoietic protoporphyria. (27 Sep 1997) |
| carbon dioxide blood level | A measure of the bicarbonate level in the blood based on a venipuncture specimen. The serum carbon dioxide is one of the normally reported values in the electrolytes profile. Lower levels of carbon dioxide indicate an acidosis. The normal level is 20 to 29 mEq/L. Lower than normal levels can indicate diabetic ketoacidosis, lactic acidosis, alcoholic ketoacidosis, kidney disease, renal failure, diarrhoea, Addison's disease, ethylene glycol poisoning or methanol poisoning. Greater than normal levels can be seen with excessive vomiting, hyperaldosteronism and Cushing's syndrome. (27 Sep 1997) |
| vasopressin level | This test measures the amount of ADH in the serum. It is used to detect disorders that may affect the level of ADH in the serum. Normal values are: 0 to 4.7 pg/ml. Elevated ADH levels can indicate a CNS infection, fluid imbalance, CNS tumour, SIADH or acute porphyria. Low levels can indicate: diabetes insipidus or damage to the pituitary gland. (27 Sep 1997) |
| mean sea level | <marine biology> A tidal datum: the arithmetic mean of hourly water elevations observed over a specific 19-year cycle. Points on land can be referenced to a mean sea level, in which case the datum assumes zero elevation. (09 Oct 1997) |
| gray level also gray value | <microscopy> The brightness of pixels in a digitised video image, commonly expressed in integers ranging from 0 (black) to 255 (white) for an 8-bit digital signal. (05 Aug 1998) |