Spinal epidural abscess - a rare complication of Crohn´s disease: case report.

Spinal epidural abscess (SEA) is a rare disease that occurs mainly in immunocompromised patients after spinal surgery or spinal trauma and can lead to a severe neurological deficit or even death if diagnosed too late. However, cases of SEA have also been reported in patients with fistulising Crohn´s disease (CD). We present a case of a young patient with CD and a history of relapsing perianal disease followed by a complication of SEA in the thoracic spine. In close cooperation with the orthopedists and the neurologists, the gastroenterologists have successfully treated the SEA in this patient, allowing her to return back to biological treatment for CD.

A myristoyl switch at the plasma membrane triggers cleavage and oligomerization of Mason-Pfizer monkey virus matrix protein.

For most retroviruses, including HIV, association with the plasma membrane (PM) promotes the assembly of immature particles, which occurs simultaneously with budding and maturation. In these viruses, maturation is initiated by oligomerization of polyprotein precursors. In contrast, several retroviruses, such as Mason-Pfizer monkey virus (M-PMV), assemble in the cytoplasm into immature particles that are transported across the PM. Therefore, protease activation and specific cleavage must not occur until the pre-assembled particle interacts with the PM. This interaction is triggered by a bipartite signal consisting of a cluster of basic residues in the matrix (MA) domain of Gag polyprotein and a myristoyl moiety N-terminally attached to MA. Here, we provide evidence that myristoyl exposure from the MA core and its insertion into the PM occurs in M-PMV. By a combination of experimental methods, we show that this results in a structural change at the C-terminus of MA allowing efficient cleavage of MA from the downstream region of Gag. This suggests that, in addition to the known effect of the myristoyl switch of HIV-1 MA on the multimerization state of Gag and particle assembly, the myristoyl switch may have a regulatory role in initiating sequential cleavage of M-PMV Gag in immature particles.