APPLICATION OF COMPUTER-ASSISTED MORPHOMETRY TO THE ANALYSIS OF PRENATAL DEVELOPMENT OF HUMAN LUNG

Morphometry is well-established in tumour pathology. To evaluate its p otential usefulness for description of developmental processes, histol ogical slides from paraffin-embedded specimens of 67 human fetal lungs were Feulgen-stained, and morphometric characteristics of nuclei of e pithelial pulmonary cells were analysed with an automated image analys is system. The measured cytometric features comprised of integrated op tical density (IOD), S-phase-related IOD fraction, IOD entropy and nuc lear area. Histometric features of the specimens were based upon the m inimum spanning tree (MST) and included distances between neighboring epithelial cells, between epithelial cells and neighboring lymphocytes , and assessment of MST entropy. Notably, certain parameters revealed a non-uniform level during prenatal development. S-phase-related IOD f raction increased from 5% to 8% between 14 and 16 weeks of gestation, then declined to 6% until birth. The IOD entropy steadily increased du ring development, whereas the extent of nuclear area remained constant . In accordance with an increase of the S-phase-related fraction the M ST entropy displayed a singular peak between 14 and 16 weeks of gestat ion, which is probably associated with development of glandular struct ures in the lung. Correlation of expression of binding sites for marke rs, presumably involved in functional aspects of development, with suc h alterations, is shown for binding capacities of biotinylated fucoida n and the S-phase-related fraction. This may be helpful to infer immun o- or ligando histochemically defined tissue sites with potential phys iological significance in morphometrically distinguished periods of de velopment.