Foraminal stenosis and radiculopathy secondary to tophaceous gout: illustrative case.

BACKGROUND: Tophaceous gout is a severe form of gout that results in the formation of large nodules, or tophi, in the affected joints and surrounding tissues. Gouty tophi in the spine have a constellation of presentations that often mimic other pathologies and may not be easily discernable from more common pathologic processes. OBSERVATIONS: A 47-year-old female with a history of chronic renal disease, obesity, gout, inflammatory polyarthritis, and multiple sclerosis presented with 6 months of low-back pain and lumbar radiculopathy affecting the right lower extremity. A lumbar magnetic resonance imaging study revealed right foraminal stenosis and spondylolisthesis at levels L4-5. An intraspinal extradural mass was noted adjacent to the traversing right L5 and exiting right L4 nerve roots. A bilateral decompressive laminectomy, facetectomy, and foraminotomy of L4-5 was performed. A calcific, chalky-white mass was discovered in the foramen, and pathology determined the specimen to be a gout tophus. Postoperatively, the patient endorsed the resolution of her preoperative symptoms, which have not returned on follow-up. LESSONS: Reports of gouty depositions compressing the spinal cord in the current literature are relatively rare. Although the diagnosis of gouty tophi can only be confirmed histologically, patient history may serve as a helpful diagnostic tool.

Human Left Anterior Cingulate Stimulation Elicits a Reproducible Micturition Response.

Electrical stimulation of a brain region producing a micturition response has never previously been described in the human. This report identifies the anterior cingulate gyrus as a brain region important in the micturition response. Stereo electroencephalography was performed in a 38-year-old female with medically refractory epilepsy. The response of the left anterior cingulate from low- to high-frequency brain stimulation was tested. Stimulation within the left anterior cingulate resulted in a reproducible micturition response. The response was dependent on the frequency of stimulation (present with stimulation at 50-150 Hz and not present at 5 or 350 Hz). These results provide evidence for the presence of a region within the human left anterior cingulate gyrus involved in producing the micturition response. This may have implications in the understanding of the physiological mechanisms of willful micturition and in the treatment of bladder disorders.

Identification of a key cholesterol binding enhancement motif in translocator protein 18 kDa.

Translocator protein 18 kDa (TSPO) in the mitochondrial outer membrane has been implicated in cholesterol transport regulating steroidogenesis. A human single polymorphism associated with anxiety disorders (A147T) and reduced pregnenolone production is adjacent to TSPO's cholesterol binding motif. In a mutant mimicking this polymorphism, we observe a lower level of binding of cholesterol. Further, three residues preceding A147 are more hydrophilic in a bacterial TSPO that has an affinity for cholesterol 1000-fold lower than that of the human form. Converting these residues to the human form in the bacterial homologue strikingly increases the affinity for cholesterol. An important role for this extended motif is further supported by covariance analysis.