Nucleocytoplasmic Ratio

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nucleocytoplasmic ratio

[¦nü·klē·ō‚sīd·ə′plaz·mik ′rā·shō]
(cell and molecular biology)
The ratio between the measured cross-sectional area or estimated volume of the nucleus of a cell to the volume of its cytoplasm. Also known as karyoplasmic ratio.

Nucleocytoplasmic Ratio


(also nucleoplasmic ratio), in biology, the ratio of nuclear to cytoplasmic volume. The ratio was introduced in 1908 by the German scientist R. Hertwig, who believed that regular decrease in the nucleocytoplasmic ratio was the immediate cause of the initiation of cell division. Hertwig’s hypothesis has not been confirmed. The volume of the nucleus is usually directly proportional to the volume of the cytoplasm, including the case of polyploidy of the nucleus. However, many exceptions to this proportionality are known, for example, in the development of egg cells or in changes of the functional activity of a cell. Cells of different tissues have different nucleocyto-plasmic ratios; therefore, the ratios are used to characterize cell types.

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The epithelium within this pseudopapillary lesion showed an increased nucleocytoplasmic ratio, round large nuclei, and prominent nucleoli (Figure 1, B).
7,15) Histologic features of malignant GCTs include necrosis, spindling, vesicular nuclei with prominent nucleoli, high nucleocytoplasmic ratio, cellular pleomorphism, and mitotic figures (>2 mitoses/10 HPF).
The cells were cuboidal in the hyperplastic and papillary areas, with an increased nucleocytoplasmic ratio, round bland nuclei with low mitotic activity, and inconspicuous nucleoli (Figure 1).