Radiographic findings in the nail-patella syndrome.

Nail-patella syndrome is a rare disorder characterized classically by the tetrad of nail hypoplasia or aplasia, aplastic or hypoplastic patellae, elbow dysplasia, and the presence of iliac horns. Iliac horns are considered pathognomonic, and the presence of hypoplastic or aplastic patellae in conjunction with nail abnormalities is a cardinal feature of diagnosis. Elbow dysplasia is present in most cases and can exhibit features typical of the syndrome. Herein we present the radiographic findings of the elbows, knees, and pelvis of a woman with nail-patella syndrome.

Mucocele of the appendix.

Mucocele of the appendix is a term used to describe a dilated, mucin-filled appendix. It is most commonly the result of epithelial proliferation, but can be caused by inflammation or obstruction of the appendix. Two cases of mucocele of the appendix are presented with a discussion of the histologic and radiologic features as well as the surgical management.

Abdominal apoplexy: two unusual cases of hemoperitoneum.

Abdominal apoplexy, or idiopathic spontaneous intraperitoneal hemorrhage, is a rare and often fatal condition resulting from a variety of disease processes affecting the arterial and venous abdominal vasculature. Preoperative and intraoperative diagnosis and treatment of abdominal apoplexy are challenging. The source of bleeding may remain elusive even after careful autopsy dissection given the absence of intravascular pressure. Despite these challenges, early diagnosis and rapid treatment remain central to a successful outcome, as nonsurgical mortality has approached 100%. Presented here are two fatal cases of abdominal apoplexy, one involving a patient with arterial dissection of the gastroduodenal artery and one involving rupture of the superior mesenteric-portal venous system with perivascular pseudoaneurysm formation.

Rules for nuclear localization sequence recognition by karyopherin beta 2.

Karyopherinbeta (Kapbeta) proteins bind nuclear localization and export signals (NLSs and NESs) to mediate nucleocytoplasmic trafficking, a process regulated by Ran GTPase through its nucleotide cycle. Diversity and complexity of signals recognized by Kap betas have prevented prediction of new Kap beta substrates. The structure of Kap beta 2 (also known as Transportin) bound to one of its substrates, the NLS of hnRNP A1, that we report here explains the mechanism of substrate displacement by Ran GTPase. Further analyses reveal three rules for NLS recognition by Kap beta 2: NLSs are structurally disordered in free substrates, have overall basic character, and possess a central hydrophobic or basic motif followed by a C-terminal R/H/KX(2-5)PY consensus sequence. We demonstrate the predictive nature of these rules by identifying NLSs in seven previously known Kap beta 2 substrates and uncovering 81 new candidate substrates, confirming five experimentally. These studies define and validate a new NLS that could not be predicted by primary sequence analysis alone.