Placentation defects are highly prevalent in embryonic lethal mouse mutants.

Large-scale phenotyping efforts have demonstrated that approximately 25-30% of mouse gene knockouts cause intrauterine lethality. Analysis of these mutants has largely focused on the embryo and not the placenta, despite the crucial role of this extraembryonic organ for developmental progression. Here we screened 103 embryonic lethal and sub-viable mouse knockout lines from the Deciphering the Mechanisms of Developmental Disorders program for placental phenotypes. We found that 68% of knockout lines that are lethal at or after mid-gestation exhibited placental dysmorphologies. Early lethality (embryonic days 9.5-14.5) is almost always associated with severe placental malformations. Placental defects correlate strongly with abnormal brain, heart and vascular development. Analysis of mutant trophoblast stem cells and conditional knockouts suggests that a considerable number of factors that cause embryonic lethality when ablated have primary gene function in trophoblast cells. Our data highlight the hugely under-appreciated importance of placental defects in contributing to abnormal embryo development and suggest key molecular nodes that govern placenta formation

Study of the Radical vs. Conservative Surgical Treatment of the Hepatic Hydatid Cyst: A 10-Year Experience

The hepatic hydatid cyst is a major health problem in endemic areas. Surgery is still the best choice for the treatment of hydatid cyst of the liver. There is controversy regarding efficacy of radical versus conservative surgical approaches. In this study, we aimed to evaluate the two surgical methods in patients treated for the hepatic hydatid cyst. This is a retrospective review of the medical records of 135 patients who underwent surgery for the hepatic hydatid cyst from 1993 to 2003. Surgery comprised conservative methods (evacuation of the cyst content and excision of the inner cyst layers) and radical methods (total excision of the cyst and removal of its outer layer). One hundred thirty five patients underwent liver surgery. Conservative surgery was performed for 71 (53%), whereas, the remaining 64 patients (47%) underwent radical surgery. Local recurrence rate of the cysts was lower in the radical versus conservative surgery group and the mean length of hospital stay was shorter in the radical surgery group. Radical surgery of the hepatic hydatid cyst may be the preferred treatment because of its low rate of local recurrence, as well as short hospital stay