Spontaneous Unilateral Intrasphenoidal Meningocele.

The sphenoid sinus is an uncommon location for protrusion of a meningocele. When this does occur, it nearly always presents with leakage of cerebrospinal fluid through the nasal cavity. We present a case of a 38-year-old female found to have a meningocele protruding into the left sphenoid sinus, who presented with intractable headache but no CSF rhinorrhea. The lesion was discovered on computed tomography angiography, which was performed in order to rule out intracranial pathology as the etiology of her headache. Prior imaging, including pre- and post-contrast MRI, demonstrated the fluid within the sphenoid sinus, but did not reveal the communication through a defect in the base of the skull. Thus, it was assumed to be strictly related to sinus disease in the past. Our case represents a phenomenon whereby meningoceles protruding through the basilar skull into the sphenoid sinus or any other location are potentially misdiagnosed due to poor visualization of the osseous defect and lack of awareness of this entity.

Magnetic resonance imaging findings in a patient with cryopyrin-associated periodic syndrome: A rare hereditary multi-system inflammatory disorder.

Cryopyrin-associated periodic syndrome is a hereditary inflammatory disorder encompassing a wide spectrum of clinical phenotypes. This disorder has been associated with mutation of the NLRP3 gene coding for cryopyrin, which leads to overproduction of interleukin-1. The condition causes relapsing bouts of inflammation involving multiple organ systems, including the central nervous system, and, if untreated, can lead to long-term debilitating effects. A literature review revealed only a few brief descriptions of magnetic resonance imaging findings in cryopyrin-associated periodic syndrome patients. We describe serial magnetic resonance imaging findings in an 11-year-old female with clinically diagnosed cryopyrin-associated periodic syndrome who presented with intermittent headaches, progressive sensorineural hearing loss, fevers, and abdominal pain. The magnetic resonance imaging showed progressively worsening low T2 signal in the cochlea, cochlear enhancement, and leptomeningeal enhancement. We also describe some previously unreported findings in this syndrome, including cranial nerve and cauda equina enhancement.

A Single Legionella Effector Catalyzes a Multistep Ubiquitination Pathway to Rearrange Tubular Endoplasmic Reticulum for Replication.

Intracellular pathogens manipulate host organelles to support replication within cells. For Legionella pneumophila, the bacterium translocates proteins that establish an endoplasmic reticulum (ER)-associated replication compartment. We show here that the bacterial Sde proteins target host reticulon 4 (Rtn4) to control tubular ER dynamics, resulting in tubule rearrangements as well as alterations in Rtn4 associated with the replication compartment. These rearrangements are triggered via Sde-promoted ubiquitin transfer to Rtn4, occurring almost immediately after bacterial uptake. Ubiquitin transfer requires two sequential enzymatic activities from a single Sde polypeptide: an ADP-ribosyltransferase and a nucleotidase/phosphohydrolase. The ADP-ribosylated moiety of ubiquitin is a substrate for the nucleotidase/phosphohydrolase, resulting in either transfer of ubiquitin to Rtn4 or phosphoribosylation of ubiquitin in the absence of a ubiquitination target. Therefore, a single bacterial protein drives a multistep biochemical pathway to control ubiquitination and tubular ER function independently of the host ubiquitin machinery.