Shuta Aketa

ATP-dependent potassium channel mediates neuroprotection by chemical preconditioning with 3-nitropropionic acid in gerbil hippocampus.

Chemical preconditioning with low dose of 3-nitropropionic acid (3-NPA) prolongs the latency to hypoxic depolarization (HD), which triggers cell death, and also restores the synaptic transmission which disappears during hypoxia in gerbil hippocampal slices. Here we show that these neuroprotective effects are mediated by the activation of K(ATP) channels. Diazoxide, a K(ATP) channel opener, prolonged the latency to HD dose-dependently to the same extent as that of the chemical preconditioning with 3-NPA. Glibenclamide, a K(ATP) channel blocker, abrogated the prolongation of HD with 3-NPA. The hypoxic tolerance of synaptic transmission with 3-NPA was also abolished by glibenclamide. Diazoxide also induced the hypoxic tolerance of synaptic transmission. Theses results suggest that K(ATP) channel is involved in the neuroprotection afforded by the chemical preconditioning.

Relationship Between Clinical Features and T2-Weighted Magnetic Resonance Images in Symptomatic Rathke Cleft Cysts

BACKGROUND It is not known when surgery is appropriate for the treatment for incidental Rathke cleft cysts because knowledge of their natural history is lacking. In this study, we sought to determine whether symptomatic Rathke cleft cysts could be distinguished by their signal intensities in magnetic resonance (MR) images. We analyzed the relationship between these signal intensities and clinical manifestations of the cysts and their patterns of expansion. METHODS MR signal intensities on T1-weighted (T1W) and T2-weighted (T2W) images for 52 cases were categorized into 3 types. Type 1 (20 cases) showed low signal intensities on T1W images and hyperintensity on T2W images. Type 2 (10 cases) showed hyperintensity on both T1W and T2W images. Type 3 (22 cases) showed hypointensity on T2W images. RESULTS A significantly higher proportion of patients with type 1 signal intensities had large cysts compressing their third ventricle than patients with the other 2 types of signal intensities. Patients with type 1 signal intensities also frequently had visual disturbances. Anterior pituitary dysfunction was observed more often in patients with type 2 or 3 signal intensities than in patients with type 1 intensities. CONCLUSIONS We conclude that Rathke cleft cysts that show an MR signal intensity similar to that of cerebrospinal fluid grow slowly and are frequently diagnosed as cysts associated with visual disturbance when they become large. It may be possible to predict the clinical progression of Rathke cleft cysts by assessing MR signal intensities.

Transdural Indocyanine Green Videography for Superficial Temporal Artery–to–Middle Cerebral Artery Bypass—Technical Note

BACKGROUND Neurosurgical application of indocyanine green (ICG) videography before performing a dural opening, known as transdural ICG videography, has been used during surgery of meningiomas associated with venous sinuses as well as cranial and spinal arteriovenous malformations. However, its use for a superficial temporal artery (STA)-to-middle cerebral artery (MCA) bypass has not been reported. METHODS We performed a retrospective analysis of medical records of patients who underwent transdural ICG videography during STA-MCA bypass performed between January 2012 and March 2015. The primary outcome was visualization of recipient cortical arteries; secondary outcomes were surgical modifications and complications as well as any adverse events associated with transdural ICG videography. RESULTS We analyzed 29 STA-MCA bypass procedures performed in 30 hemispheres with atherosclerotic steno-occlusive disease and found that the proper recipient was identified in 28 hemispheres. Subsequently modified procedures for those were a tailored dural incision and craniotomy correction. No complications associated with ICG administration were encountered; during the postoperative course, transient aphasia was noted in 1 case, chronic subdural hematoma was noted in 1 case, and subdural effusion was noted in 2 cases. CONCLUSIONS Transdural ICG videography for atherosclerotic steno-occlusive disease facilitates modifications during STA-MCA bypass procedures. Recognition of the proper recipient cortical arteries before a dural incision allows the neurosurgeon to perform a tailored dural incision and extension of the bone window, although the contribution to surgical outcome has yet to be determined.

Endovascular Therapy for the Steal Phenomenon due to the Innominate Artery Severe Stenosis and Bilateral Internal Carotid Artery Severe Stenosis

BACKGROUND Symptomatic innominate artery stenosis presenting as hemodynamic bilateral cerebral ischemia is uncommon. We present a rare case of the severe stenosis of the origin of an innominate artery and severe stenosis of bilateral internal carotid artery that induced hemodynamic cerebral ischemia after ipsilateral axillary artery-bilateral femoral artery bypass and was treated with stent replacement of the innominate artery and right internal carotid artery. CASE REPORT A 64-year-old woman who previously had undergone right axillary artery-bilateral femoral artery anastomosis for abdominal aorta high obstruction had been suffering from chronic dizziness and so visited our department. Findings of the examination included the severe stenosis of the origin of an innominate artery and severe stenosis of bilateral internal carotid artery, causing hemodynamic cerebral ischemia. She underwent stent replacement of the innominate artery and right carotid artery stenting via a right transbrachial approach. Her symptoms were relieved postoperatively. DISCUSSION For the sake of improving the hemodynamic cerebral ischemia, we performed stent replacement for innominate artery stenosis and right carotid artery stenting. Endovascular treatment of subclavian and innominate artery disease is a safe procedure. In addition, for the protection of thromboembolic migration, we performed balloon protection of the external carotid artery and filter protection of the internal carotid artery. CONCLUSIONS Stent replacement for these lesions can be performed safely with the right approach and protection methods, even when the only accessible route is the right brachial artery.