[Morphological detection of placental anticoagulant protein-I (PAP-I) in human placenta]

It has been reported that placental anticoagulant protein-I (PAP-I) inhibits the intrinsic and extrinsic pathways of blood coagulation and also the reconstituted prothrombinase activity. However, morphological study on the distribution of PAP-I in whole placenta or in placental cells has not been reported yet. We detected the PAP-I antigen, under light- and electron-microscope, by mean of immuno-cytological techniques. PAP-I was also present in microvilli of the placental syncytiotrophoblast cells and their cortical cytoplasm beneath the villi.