title: Platelet inhibitory activity in placentas from normal and abnormal pregnancies.
abstract: Retroplacental blood flow requires inhibition of coagulation in the absence of an endothelial lining. We confirmed that trophoblast releases an inhibitor of platelet aggregation which functions via degradation of adenosine diphosphate. This inhibitor appears to be deficient in some pregnancies with abruptio placentae and intrauterine growth retardation. Unimpeded retroplacental blood flow may depend upon the local inhibition of platelet aggregation. Placental tissue contains an inhibitor of platelet aggregation which appears to be an adenosine diphosphatase distinct from heat-stable alkaline phosphatase. Placental tissue from patients with abruptio placentae contains abnormally low amounts of this enzyme.
authors.forename: W F
authors.initials: WF
authors.lastname: O'Brien
authors.forename: R A
authors.initials: RA
authors.lastname: Knuppel
authors.forename: H I
authors.initials: HI
authors.lastname: Saba
authors.forename: J L
authors.initials: JL
authors.lastname: Angel
authors.forename: R
authors.initials: R
authors.lastname: Benoit
authors.forename: A
authors.initials: A
authors.lastname: Bruce
mesh_terms: D000037:Abruptio Placentae / Q000201:enzymology; D000244:Adenosine Diphosphate / Q000378:metabolism*; D001081:Apyrase / Q000378:metabolism*; D005260:Female; D005317:Fetal Growth Retardation / Q000201:enzymology; D006801:Humans; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010920:Placenta / Q000201:enzymology*; D010924:Placental Extracts / Q000032:analysis; D010974:Platelet Aggregation; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000201:enzymology
chemical_list: D010924:Placental Extracts; D000244:Adenosine Diphosphate; D010744:Phosphoric Monoester Hydrolases; D001081:Apyrase