The surface coating of the pneumonocytes in human neonatal lung

The surface coating of the pneumonocytes in the lungs of five human neonates was studied by conventional electron microscopy and by cytochemical techniques. These techniques included staining with colloidal iron oxide, cationic ferritin, Ruthenium red, Ruthenium hexamine trichloride, high iron diamine and the periodic acid-thiocarbohydrazide-silver proteinate sequence. The results of the study indicate that the surface-bound coat of the pneumonocytes in human neonatal lung is a periodate-reactive sialomucin.