1. SYN: metamorphosis. 2. A change of one tissue into another, as cartilage into bone. 3. In metals, a change in phase and physical properties in the solid state caused by heat treatment. 4. In microbial genetics, transfer of genetic information between bacteria by means of “naked” intracellular DNA fragments derived from bacterial donor cells and incorporated into a competent recipient cell. [L. trans-formo, pp. -atus, to transform]
- cavernous t. of portal vein replacement of the portal vein by a number of collateral channels, a consequence of thrombosis.
- cell t. morphologic and physiologic changes including loss of contact inhibition resulting from infection of an animal cell by an oncogenic virus.
- Haldane t. the multiplication of inspired oxygen concentration by the ratio of expired to inspired nitrogen concentrations in the calculation of oxygen consumption or respiratory quotient by the open circuit method.
- Lobry de Bruyn -van Ekenstein t. the conversion of glucose to fructose and mannose in dilute alkali by enolization adjacent to the carbonyl group to form an enediol, a reaction analogous to certain biochemical transformations.
- logit t. a method of linearizing dose-response curves for radioimmunoassay techniques; i.e., logit B (bound)/Bo (initial binding) = log (B/Bo/1 − B/Bo).
- lymphocyte t. the t. into large, blastlike forms (immunoblasts) that occurs when lymphocytes are exposed to histoincompatible antigens (mixed lymphocyte culture) or mitogens. SEE ALSO: mixed lymphocyte culture test.
- nodular t. of the liver a rare condition in which nodules of hyperplastic hepatocytes develop without fibrosis or general loss of lobular architecture. SYN: nodular regenerative hyperplasia.

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trans·for·ma·tion .tran(t)s-fər-'mā-shən, -fȯr- n
1) an act, process, or instance of transforming or being transformed see MALIGNANT TRANSFORMATION
2 a) genetic modification of a bacterium by incorporation of free DNA from another ruptured bacterial cell compare TRANSDUCTION (2)
b) genetic modification of a cell by the uptake and incorporation of exogenous DNA

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trans·for·ma·tion (trans″for-maґshən) [trans- + formation] 1. change of form or structure; conversion from one form to another. 2. in oncology, the change that a normal cell undergoes as it becomes malignant. 3. in eukaryotes, the conversion of normal cells to malignant cells in cell culture. 4. bacterial t.

Medical dictionary. 2011.


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