| MID | maximum inhibiting dilution; mesioincisodistal; midinfarct dementia; minimum infective dose; minimum... |
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| NSD | Nairobi sheep disease; neonatal staphylococcal disease; neurosecretory dysfunction; night sleep depr... |
| TCD | tapetochoroidal dystrophy; T-cell depletion; thermal conductivity detector; tissue culture dose; tra... |
| MBD | Marchiafava-Bignami disease; Mental Deterioration Battery; methylene blue dye; minimal brain damage;... |
| MCD | magnetic circular dichroism; mast-cell degranulation; mean cell diameter; mean of consecutive differ... |
| lethal equivalent | A combination of selective effects that on average have the same impact on the composition of the gene pool as one death; e.g., two carriers at 50% risk of dying would be the lethal equivalent of one carrier at 100% risk, in the population genetics of recessive traits lethal equivalent is expressed as twice the sum of the expected number of deaths ascribable to the genetic load. Expression used of the genetic load of recessive genes in heterozygous state that if in homozygous state would cause death or carry a risk of death. The expected number of deaths from all such genes is expressed in lethal equivalent. (05 Mar 2000) |
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| lethal factor | A disorder that prevents effective reproduction by those affected; e.g., Klinefelter syndrome. (05 Mar 2000) |
| lethal gene | A gene that produces a genotype that leads to death of the organism before reproduction is possible or that precludes reproduction; for a recessive gene the homozygous or hemizygous state is lethal. (05 Mar 2000) |
| lethal midline granuloma | Destruction of the nasal septum, hard palate, lateral nasal walls, paranasal sinuses, skin of the face, orbit and nasopharynx by an inflammatory infiltrate with atypical lymphocytic and histiocytic cells; presumably a form of lymphoma in most cases. An obsolete term for polymorphic reticulosis. Synonym: granuloma gangrenescens, malignant granuloma, midline malignant reticulosis granuloma. (05 Mar 2000) |
| lethal mutation | <genetics, molecular biology> Mutation that eventually results in the death of an organism carrying the mutation. (18 Nov 1997) |
| absorbed dose | The amount of energy absorbed per unit mass of irradiated material at the target site; in radiation therapy, the former unit for absorbed dose is the rad; the current (S.I.) unit is the gray. (05 Mar 2000) |
| air dose | The radiation dose, expressed in roentgens, delivered at a point in free air. Synonym: air dose. (05 Mar 2000) |
| bone marrow dose | The cumulative dose to the blood-forming organ from therapeutic or nuclear fallout irradiation; the presumed leukemogenic dose. (05 Mar 2000) |
| booster dose | A dose given at some time after an initial dose to enhance the effect, said usually of antigens for the production of antibodies. (05 Mar 2000) |
| breast dose in mammography | <radiology> 180 mrad / view -- mid-breast dose, guideline: less than 1 rad for 2-view exam (12 Dec 1998) |
| maintenance dose | In chemotherapy, systematic dosage at a level that maintains protection against exacerbation. (05 Mar 2000) |
| genetically significant dose | <physics, radiobiology> The genetically significant dose is that which, if received by every member of the population, would be expected to produce the same genetic injury to the population as do the actual doses received by the individuals irradiated. Thus, the genetically significant dose is the dose equivalent to the gonads weighted for the age and sex distribution in those members of the irradiated population expected to have offspring. The genetically significant dose is expressed in sieverts (or rem). Acronym: GSD (06 Aug 1998) |
| maximal dose | <pharmacology> The largest amount of a drug or physical procedure that an adult can take with safety. (05 Mar 2000) |
| maximum permissible dose | <radiobiology> Defined by the International Commission on Radiological Protection as the greatest dose of radiation which, in the light of present knowledge, is not expected to cause detectable bodily injury to a person at any time during his lifetime. This dose has been reduced with each Commission report. The MPD is given in terms of acute or chronic exposure of the whole body or of organs, systems, or regions of the body, and differs for persons who are occupationally exposed versus the public at large. (05 Mar 2000) |
| median effective dose | The dose that produces the desired effect; when followed by a subscript (generally "ED50"), it denotes the dose having such an effect on a certain percentage (e.g., 50%) of the test animals; ED50 is the median effective dose, in radiation protection, the sum of the equivalent doses in all tissues and organs of the body weighted for tissue effects of radiation. The unit of effective dose is the sievert (Sv), epilation dose, the minimum amount of radiation sufficient to produce hair loss, usually in 10 to 14 days. (05 Mar 2000) |