| mitomycins | <chemical> A group of methylazirinopyrroloindolediones obtained from certain streptomyces strains. They are very toxic antibiotics used as antineoplastic agent in some solid tumours. Porfiromycin and mitomycin c are the most useful members of the group. Pharmacological action: antibiotics, antineoplastic. (12 Dec 1998) |
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| mitoplast | <cell biology> Isolated mitochondria without their outer membranes. They have finger like processes and retain the capacity for oxidative phosphorylation. (18 Nov 1997) |
| mitoribosome | <cell biology> Mitochondrial ribosomes, these more closely resemble prokaryotic ribosomes than cytoplasmic ribosomes of the cells in which they are found, though they are even smaller and have fewer proteins than bacterial ribosomes. Origin: Gr. Soma = body (18 Nov 1997) |
| mitosis | <cell biology> A method of indirect division of a cell, consisting of a complex of various processes, by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes characteristic of the somatic cells of the species. Mitosis, the process by which the body grows and replaces cells, is divided into four phases. 1. Prophase: formation of paired chromosomes, disappearance of nuclear membrane, appearance of the achromatic spindle, formation of polar bodies. 2. Metaphase: arrangement of chromosomes in the equatorial plane of the central spindle to form the monaster. Chromosomes separate into exactly similar halves. 3. Anaphase: the two groups of daughter chromosomes separate and move along the fibres of the central spindle, each toward one of the asters, forming the diaster. 4. Telophase: the daughter chromosomes resolve themselves into a reticulum and the daughter nuclei are formed, the cytoplasm divides, forming two complete daughter cells. NOTE: the term mitosis is used interchangeably with cell division, but strictly speaking it refers to nuclear division, whereas cytokinesis refers to division of the cytoplasm. In some cells, as in many fungi and the fertilized eggs of many insects, nuclear division occurs within the cell unaccompanied by division of the cytoplasm and formation of daughter cells. (13 Nov 1997) |
| mitotane | <chemical> 1-chloro-2-(2,2-dichloro)-1-(4-chlorophenyl)ethylbenzene. A derivative of the insecticide ddd that specifically inhibits cells of the adrenal cortex and their production of hormones. It is used to treat adrenocortical tumours and causes CNS damage, but no bone marrow depression. Pharmacological action: antineoplastic agent, hormonal. Chemical name: Benzene, 1-chloro-2-(2,2-dichloro-1-(4-chlorophenyl)ethyl)- (12 Dec 1998) |
| mitotic | Pertaining to mitosis. (12 Dec 1998) |
| mitotic apparatus | See: mitosis, spindle fibre. (18 Nov 1997) |
| mitotic cell selection | A drug-free procedure for the selection of mitotic cells from an exponentially growing monolayer. (09 Oct 1997) |
| mitotic cycle | <cell biology, molecular biology> The sequence of events between mitotic divisions. The cycle is conventionally divided into G0, G1, (G standing for gap), S (synthesis phase during which the DNA is replicated), G2 and M (mitosis). Cells that will not divide again are considered to be in G0 and the transition from G0 to G1 is thought to commit the cell to completing the cycle and dividing. (26 Mar 1998) |
| mitotic death | <cell biology> Cells fatally damaged by ionising radiation may not die until the next mitosis, at which point the radiation damage to the DNA becomes evident, particularly when there is fragmentation of chromosomes. (18 Nov 1997) |
| mitotic division | <cell biology> A method of indirect division of a cell, consisting of a complex of various processes, by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes characteristic of the somatic cells of the species. Mitosis, the process by which the body grows and replaces cells, is divided into four phases. 1. Prophase: formation of paired chromosomes, disappearance of nuclear membrane, appearance of the achromatic spindle, formation of polar bodies. 2. Metaphase: arrangement of chromosomes in the equatorial plane of the central spindle to form the monaster. Chromosomes separate into exactly similar halves. 3. Anaphase: the two groups of daughter chromosomes separate and move along the fibres of the central spindle, each toward one of the asters, forming the diaster. 4. Telophase: the daughter chromosomes resolve themselves into a reticulum and the daughter nuclei are formed, the cytoplasm divides, forming two complete daughter cells. NOTE: the term mitosis is used interchangeably with cell division, but strictly speaking it refers to nuclear division, whereas cytokinesis refers to division of the cytoplasm. In some cells, as in many fungi and the fertilized eggs of many insects, nuclear division occurs within the cell unaccompanied by division of the cytoplasm and formation of daughter cells. (13 Nov 1997) |
| mitotic figure | The microscopic appearance of a cell undergoing mitosis; a cell of which the chromosomes are visible by the light microscope. (05 Mar 2000) |
| mitotic index | <cell biology, molecular biology> The fraction of cells in a sample that are in mitosis. It is a measure of the relative length of the mitotic phase of the cell cycle. (18 Nov 1997) |
| mitotic nondisjunction | Failure of the two members of a chromosome pair to separate (disjoin) during mitosis so that both go to one daughter cell and none to the other. (12 Dec 1998) |
| mitotic period | The period of the cell cycle in which all phases of mitosis occur. Synonym: M phase. (05 Mar 2000) |