Application of computer-assisted morphometry to the analysis of prenatal development of human lung.

Morphometry is well-established in tumour pathology. To evaluate is potential usefulness for description of developmental processes, histological slides from paraffin-embedded specimens of 67 human fetal lungs were Feulgen-stained, and morphometric characteristics of nuclei of epithelial pulmonary cells were analysed with an automated image analysis system. The measured cytometric features comprised of integrated optical density (IOD), S-phase-related IOD fraction, IOD entropy and nuclear area. Histometric features of the specimens were based upon the minimum 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 fraction increased from 5% to 8% between 14 and 16 weeks of gestation, then declined to 6% until birth. The IOD entropy steadily increased during development, whereas the extent of nuclear area remained constant. In accordance with an increase of the S-phase-related fraction the MST entropy displayed a singular peak between 14 and 16 weeks of gestation, which is probably associated with development of glandular structures in the lung. Correlation of expression of binding sites for markers, presumably involved in functional aspects of development, with such alterations, is shown for binding capacities of biotinylated fucoidan and the S-phase-related fraction. This may be helpful to infer immuno- or ligando histochemically defined tissue sites with potential physiological significance in morphometrically distinguished periods of development.

Mouse heparin binding protein-44 (HBP-44) associates with brushin, a high-molecular-weight glycoprotein antigen common to the kidney and teratocarcinomas.

Heparin binding protein-44 (HBP-44) is a heparin binding protein of 44 kDa, found by cDNA cloning using antibodies against teratocarcinoma glycoproteins [Furukawa, T. et al. (1990) J. Biochem. 108, 297-302]. The N-terminal sequence analysis reported in this publication establishes the structure of its mature form. Immunohistochemical staining revealed that HBP-44 was located in the tubular brush border of the kidney. HBP-44 formed a complex with brushin, a high molecular weight (450 kDa) glycoprotein antigen common to the kidney and teratocarcinoma, but not with OR8 antigen, another antigen (350 kDa) of the same category. Brushin was shown to be the mouse counterpart of rat Heymann nephritis antigen, called gp330. The association between HBP-44 and brushin was revealed not only by co-precipitation upon indirect immunoprecipitation, but also by ligand blotting with HBP-44-maltose binding protein fusion protein. Calcium ion stabilized the association. Disulfide bonds in brushin seemed to be necessary for the complex formation, since reductive cleavage of the bonds resulted in failure of the protein to associate with HBP-44 in a ligand blotting experiment. Association of HBP-44 with brushin occurred both in teratocarcinoma cells, in which these molecules are mainly located in extraembryonic endoderm cells, and in the kidney, suggesting that the complex has an unknown common function in the renal tubular brush border and the extraembryonic endoderm.