Craniovertebral Junction Instability in the Setting of Chiari Malformation.

Described in the seminal paper by Hans Chiari in 1891, the Chiari I malformation (CMI) is a radiographic diagnosis commonly encountered by neurosurgeons and is often treated surgically with generally positive clinic outcomes. Studies have documented that 1% to 4% of patients undergoing MRI of the brain or cervical spine will be diagnosed with CMI, characterized by greater than 5 mm tonsillar herniation below the foramen magnum. More recently CMI has been described as a spectrum of disease, which includes Chiari 0, Chiari 1.5, and the complex Chiari. Primarily through multicenter clinical outcomes research, our understanding of the pathology continues to evolve.

Cognitive and functional status after vein of Galen aneurysmal malformation endovascular occlusion.

AIM: To study the clinical outcomes of treating vein of Galen aneurysmal malformations (VGAM), we assessed our patient cohort using standardized cognitive and functional measures. METHODS: A retrospective review of patients with VGAM treated by a single practitioner between 2003 and 2009 was performed for this study. In addition to routine clinical assessment, all patients were evaluated for cognitive and functional impairment using validated measures including the Neurobehavioral Rating Scale-Revised, the Bicêtre outcome score, and the Barthel index. RESULTS: Five patients underwent combined transarterial and transvenous embolization of their VGAM during the study period. VGAMs were classified based on angioarchitecture as either choroidal (1/5) or mural (4/5) according to the classification scheme of Lasjaunias. In total, 13 embolization procedures were performed consisting of 1 to 3 treatment stages per patient. Complete or near complete occlusion was achieved in 4 patients, while subtotal occlusion was achieved in 1 patient. During follow-up (median 62.6 mo), all patients were either unchanged or cognitively and neurologically intact. CONCLUSION: VGAM can be safely and effectively treated by staged transarterial and transvenous embolization. Using this strategy, excellent long-term cognitive and functional outcomes can be achieved.

Defining the mechanisms of CD8 T-cell tumor tolerance.

CD8 T-cell inhibition by myeloid-derived suppressor cells (MDSCs) is one of the presumed methods by which tumors evade the immune system, although the mechanism remains unclear. This paper provides a new insight into the inhibitory interactions between MDSCs and T cells and the mechanisms by which this occurs. The authors demonstrated that tumor-mediated CD8 T-cell suppression via MDSCs causes T cells to be suppressed only for the T-cell receptor (TCR) specific for the tumor-derived antigen while remaining responsive to antigens activating other TCRs in the same cell. They further show that the specific TCR complex is nitrated by the MDSC, which reduces the physical interaction of TCRs with CD3ζ and CD8 and results in lower levels of several TCR-related molecules, including phosphorylated CD3ζ, and reduces activation, proliferation and IFN-γ production in response to the specific antigen of the TCR only. This article will move the field of tumor immunology forward by identifying potential therapeutic targets as well as advancing a mechanistic knowledge to guide further research.