Placental leucine aminopeptidase might regulate the effects of oxytocin with resolution in endothelial cells.

BACKGROUND: Oxytocin (OT) is known to cause vascular relaxation via nitric oxide (NO) production and proliferation of endothelial cells. Previously we revealed that human umbilical vascular endothelial cells (HUVECs) expresses placental leucine aminopeptidase (P-LAP)/insulin regulated aminopeptidase (IRAP), which becomes translocation to the cell surface on activation of oxytocin receptor (OTR). However, the physiological roles of P-LAP in HUVECs have not been elucidated. MATERIAL/METHODS: Actions of OT on HUVECs transfected with a copy of the human P-LAP gene were therefore examined with a focus on changes in parameters linked to OTR such as calcium mobilization, NO production and cell proliferation. RESULTS: Cell surface P-LAP activity was significantly elevated (approximately 3 fold) in P-LAP overexpressing-HUVECs and overexpression of P-LAP resulted in remarkable inhibition of OT effects on HUVECs such as cell proliferation, [Ca2+]i, and NO production. CONCLUSIONS: These findings suggested that P-LAP on the plasma membrane in HUVECs regulates the effects of OT with resolution around OTR.

Pure red cell aplasia and acute hepatitis during pregnancy.

Pure red cell aplasia during pregnancy is rare. We present a case in a 26-year-old pregnant woman, referred to our hospital at 31 weeks' gestation because of severe anemia caused by acute hepatitis. She was treated with repeated blood transfusions and the pure red cell aplasia gradually remitted during the pregnancy. A live infant was delivered by cesarean section at 34 weeks' gestation. Postpartum, the pure red cell aplasia and hemolytic anemia remitted completely. Our case illustrates that pure red cell aplasia may occur late in pregnancy associated with acute viral hepatitis and is reversible during pregnancy without any necessity for steroid therapy.