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The mitotic index is a measure of cellular proliferation. [1] It is defined as the percentage of cells undergoing mitosis in a given population of cells. Mitosis is the division of somatic cells into two daughter cells. Durations of the cell cycle and mitosis vary in different cell types. An elevated mitotic index indicates more cells are dividing.
Mitotic indexing is the oldest method of assessing proliferation and is determined by counting the number of mitotic figures (cells undergoing mitosis) through a light microscope on H&E stained sections. It is usually expressed as the number of cells per microscopic field.
In histopathology, the mitosis rate (mitotic count or mitotic index) is an important parameter in various types of tissue samples, for diagnosis as well as to further specify the aggressiveness of tumors. For example, there is routinely a quantification of mitotic count in breast cancer classification. [74]
The area provides a reference unit, for example in reference ranges for urine tests. [3]Used for grading of soft tissue tumors: Grading, usually on a scale of I to III, is based on the degree of differentiation, the average number of mitoses per high-power field, cellularity, pleomorphism, and an estimate of the extent of necrosis (presumably a reflection of rate of growth).
This is also the most common pathway of artificially induced polyploidy, where methods such as protoplast fusion or treatment with colchicine, oryzalin or mitotic inhibitors are used to disrupt normal mitotic division, which results in the production of polyploid cells. This process can be useful in plant breeding, especially when attempting to ...
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.
The cyclins are necessary for the kinase subunit to function with the appropriate substrate. The mitotic cyclins can be grouped as cyclins A & B. These cyclins have a nine residue sequence in the N-terminal region called the “destruction box”, which can be recognized by the ubiquitin ligase enzyme which destroys the cyclins when appropriate.
Altitudinal zones of Andes Mountains and corresponding communities of agriculture and livestock raised. Human populations have developed agricultural production strategies to exploit varying characteristics of altitudinal zones. Elevation, climate, and soil fertility set upper limits on types of crops that can reside in each zone.