Rapid correction of prothrombin time after low-dose recombinant factor VIIA in patients undergoing orthotopic liver transplantation

Orthotopic liver transplantation (OLTx) is associated with a major risk of blood loss resulting from portal hypertension, collateral circulation, and clotting disturbances. Application of a recombinant factor VIIa (rFVIIa) has been reported to promptly correct clotting abnormalities reducing the risk of intraoperative bleeding. This study included 8 patients who underwent OLTx for end-stage liver cirrhosis, with protrombin times (PT) exceeding the upper limit of normal by more than 4 seconds before surgery. All subjects were administered a small single intravenous dose of rFVIIa [mean 68.37 microg/kg body mass (range, 32.88-71.64)] 10 minutes prior to the skin incision. The PT was then measured 15 minutes later, following graft reperfusion, and 12 hours since drug application. All patients showed rapid correction of PT within 15 minutes after injection (median PT before injection 20.25 seconds vs 11.5 seconds after injection, P <.0001). Following the reperfusion PT was found to be prolonged again. These values are not significantly differ from those before surgery and are comparable to PT values after reperfusion in patients who did not receive rFVIIa. None of the patients developed thromboembolic complications. In conclusion, lower than recommended dose of rFVIIa caused rapid improvement in the PT shortly after injection. After reperfusion PT became prolonged again, which may account for the lack of thromboembolic complications observed in this group of patients.

Evolution of a novel adrenal cell type that promotes parental care

Cell types with specialized functions fundamentally regulate animal behaviour, and yet the genetic mechanisms that underlie the emergence of novel cell types and their consequences for behaviour are not well understood1. Here we show that the monogamous oldfield mouse (Peromyscus polionotus) has recently evolved a novel cell type in the adrenal gland that expresses the enzyme AKR1C18, which converts progesterone into 20α-hydroxyprogesterone. We then demonstrate that 20α-hydroxyprogesterone is more abundant in oldfield mice, where it induces monogamous-typical parental behaviours, than in the closely related promiscuous deer mice (Peromyscus maniculatus). Using quantitative trait locus mapping in a cross between these species, we ultimately find interspecific genetic variation that drives expression of the nuclear protein GADD45A and the glycoprotein tenascin N, which contribute to the emergence and function of this cell type in oldfield mice. Our results provide an example by which the recent evolution of a new cell type in a gland outside the brain contributes to the evolution of social behaviour.