Time dimension in histopathology

Abstract

In the liver acinus hepatocytes and littoral cells stream from the portal tract toward the terminal hepatic vein. Their average displacement trajectory was denominated as tissue radius. Since cells advance on the tissue radius in one direction, the farther a cell is the older it is, and cell age may be estimated from its position. This property is regarded as time dimension of a tissue. Since distance may be estimated by image cytometry, age determination may be incorporated in the image cytometer software. Distance may be expressed in two types of units: 1. metric e.g. microns, and 2. cell location or the number of cells separating a given cell from tissue origin. Cell age may also be expressed by two units: chronological and biological. Chronological age may be derived from the cell's displacement velocity. A hepatocyte advances daily 2 microns so that a cell at 100 microns distance is 50 days old. Biological age is defined as the cell's location on the radius. Cell location may serve as biological age unit since cells ranked according to their location are also ranked by their ages. The average acinus radius is 22 location long so that in biological age units, maximal hepatocyte life span is 22 locations. One may even say that a cell at location 5 is 2 biological units older than a cell at location 1. In order to estimate chronological age the cell has to be followed for a period of time, while biological age may be read off once from the section. There is yet another advantage for utilizing cell location as unit.(ABSTRACT TRUNCATED AT 250 WORDS)