| MCCU | mobile coronary care unit |
|---|---|
| MECTA | mobile electroconvulsive therapy apparatus |
| MICU | medical intensive care unit; mobile intensive care unit |
| MME | M-mode echocardiography; mobile medical equipment; mouse mammary epithelium |
| MMR | mass miniature radiography; masseter muscle rigidity; maternal mortality rate; measles-mumps-rubella... |
| short interspersed elements | Repetitive sequences of DNA of about 300 base pairs in length that occur about every 3000-5000 bp in the genome. (05 Mar 2000) |
|---|---|
| DNA insertion elements | Discrete transposable segments of DNA which can insert into chromosomal, phage, and plasmid DNA. Some insert at random while others are site-specific; most have not been found to exist except in the inserted state. Their insertion into a genome always produces a mutation ("insertion mutation"), and their excision frequently results in a loss of host genetic information. Types of transposable elements include is elements (insertion sequence elements), which are composed of between 700 and 1400 bases and contain no genes unrelated to insertion function and tn elements (transposon elements), which are generally larger than 1400 bases and contain genes unrelated to insertion function. The concept also includes the delta element of saccharomyces cerevisiae and the integration site. (12 Dec 1998) |
| elements | Simple substances which cannot be decomposed by chemical means. They are made up of atoms which are alike in their peripheral electronic configurations, their chemical properties, and in the number of protons in their nuclei. They may differ in the number of neutrons in their nuclei. (12 Dec 1998) |
| elements, radioactive | Chemical elements which spontaneously transmute into another element with corpuscular or electromagnetic radiation. The natural radioactive elements are all those with an atomic number above 83, and some other elements, such as potassium (atomic number 19) and rubidium (atomic number 7), which are very weakly radioactive. (12 Dec 1998) |
| trace elements | A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (12 Dec 1998) |
| labile elements | Tissue cells, as of epithelium, connective tissue, etc., that continue to multiply by mitosis during the life of the individual. (05 Mar 2000) |
| fold-back elements | A type of transposable element that possesses long inverted repeats, such that when denatured, loops are formed. (05 Mar 2000) |
| long interspersed elements | Long repetitive sequences in DNA with terminal repeats seen in human and mouse DNA. (05 Mar 2000) |
| genetic | <biology> Pertaining to reproduction or to birth or origin. (07 May 1998) |
| genetic amplification | A process for producing an increase in pertinent genetic material, particularly for increasing the proportion of plasmid DNA to that of bacterial DNA. Includes the production of extrachromosomal copies of the genes for RNA. (05 Mar 2000) |
| genetic assimilation | <genetics> A situation in which a characteristic that is normally expressed only in certain environmental situations becomes fixed in a population so that it no longer requires environmental factors to be expressed. (07 May 1998) |
| genetic association | The occurrence together in a population, more often than can be readily explained by chance, of two or more traits of which at least one is known to be genetic. (05 Mar 2000) |
| genetic block | <biochemistry, molecular biology> An obstruction in a biochemical pathway caused by a mutation that has crippled production of an enzyme critical to the pathway. (07 May 1998) |
| genetic burden | The genetic debt due to harmful mutation but as yet undischarged. (In a large population of fixed size every mutation with diminished genetic fitness will eventually become extinct and depending on the details of inheritance and phenotype must be paid for by a fixed number of genetic deaths per mutation, the genetic debt.) (05 Mar 2000) |
| genetic carrier | An unaffected heterozygote bearing a usually harmful recessive gene, a cancer that bears a dominant but latent age-dependent trait to have offspring with unbalanced karyotypes. (05 Mar 2000) |