Midline Suboccipital Unilateral Trans-Cerebellomedullary Fissure Approach for Clipping of Ruptured VA-PICA Aneurysm: Two-Dimensional Operative Video.

The vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm poses a technical challenge for microsurgical clipping due to its anatomical complexity, which requires dissection of lower cranial nerves. Endovascular treatment is regarded as a feasible first-line therapeutic option for VA-PICA aneurysm because it has an acceptable aneurysm occlusion rate and is less invasive. However, microsurgical clipping remains an effective treatment option. We present the case of a 62-year-old man who presented with subarachnoid hemorrhage (SAH) due to a ruptured VA-PICA aneurysm. Neuroradiologic examination revealed a 2-3 mm medially pointing left VA-PICA aneurysm with acute obstructive hydrocephalus due to massive SAH in the posterior cranial fossa. As the patient had acute obstructive hydrocephalus and a relatively small aneurysm, we selected clipping over endovascular treatment. Because the aneurysm was located close to the midline and anterolateral to the medulla oblongata, we approached it from the midline. A midline suboccipital craniotomy, C1 laminectomy, and drilling of the left condylar fossa were performed; a unilateral cerebellomedullary fissure opening was added; and the aneurysm was clipped. Postoperative neuroradiologic examinations revealed complete obliteration of the aneurysm. As shown in this video, unilateral cerebellomedullary fissure opening combined with adequate removal of the condylar fossa provides a wide operative field in the cerebellomedullary cistern while avoiding strong retraction of the cerebellum. We believe that this technique makes VA-PICA aneurysm clipping safe and successful. Patient consent was obtained to perform the surgery and to publish the surgical video (Video 1).

Identification and characterization of a cell division-regulating kinase AKB1 (associated kinase of Trypanosoma brucei 14-3-3) through proteomics study of the Tb14-3-3 binding proteins.

We used a proteomics approach to identify the binding partners of Trypanosoma brucei 14-3-3 (Tb14-3-3) which led to the identification of a novel kinase, AKB1. The binding between these two proteins was mediated by an amphipathic groove structure in Tb14-3-3 and 1-438 amino acid sequence of AKB1. Recombinant AKB1 but not its ATP-binding-deficient mutant (DFG to NFG) possessed an auto-phosphorylation activity as well as a kinase activity towards a peptide substrate in vitro. However, the autophosphorylation was not required for the binding of AKB1 to Tb14-3-3. Interestingly, the kinase activity of AKB1 was inhibited by calcium, and the kinase was found to utilize GTP, and dATP in addition to ATP as phospho-donors. AKB1 formed homodimers through a leucine-zipper structure. Either knockdown of AKB1 or overexpression of AKB1, but not kinase-dead AKB1 mutant, deregulated cytokinesis and cell division, suggesting that kinase activity of AKB1 is crucial for its function. Furthermore, we showed that AKB1 exists in a detergent insoluble fraction. Laser confocal microscopy revealed that the majority of AKB1 is co-localized with α-tubulin. Taken together, these findings suggest that AKB1 might regulate cytokinesis and cell division by phosphorylating cytoskeleton-associated proteins.