2D MODELING OF NUCLEUS LOCATION IN LYMPHOID-CELLS

Cytologists have seldom made a quantitative study of the location of t he nucleus within the cell. We have mathematically defined three param eters in two dimensions: the number of distinct cell/nucleus boundary contacts (Ncon), the length of such contacts (Lcon), and the degree of nucleus location eccentricity (Ecc), expressed as a function of the g reatest distance between cell and nucleus boundaries, and of the nucle us/cytoplasm ratio (N/C). Based on the analysis of 68 circular or elon gated cell and nucleus models, we identify 21 topographies, for a rang e of N/C values between 20% and 70% and for a range of cell surface ar ea values between 2900 and 6700 pixels on a hexagonal raster (256 x 25 6). Beyond 70%, a maximum of two topographies may be distinguished; be low 20% - a figure nearer a nucleolus-nucleus ratio - the relevance an d reliability of the approach are subject to some doubt. We conclude t hat the problem of describing the location of one structure within ano ther remains dependent on N/C. The method has been applied to 59 lymph oid cells on smear photographs recognized internationally by hematolog ists as characteristic of lymphoid diseases. The results show the robu stness of the combination of four criteria in relation to the overall elongation of nucleus or cell profiles, and to significant contour irr egularities. The method has demonstrated its ability to describe and q uantify,the eccentric position of the nucleus within plasmocytic lymph ocytes, and provide a further degree of discrimination.