Kazuo Koide

Striatal grafts in the ischemic striatum improve pallidal GABA release and passive avoidance.

Fetal striatal cells were grafted into the ischemic striatum of rats and pallidal GABA release, and behavioral improvement were investigated. Intraluminal occlusion of the middle cerebral artery (MCA) for 1 h induced ischemic infarcts in the lateral striatum and the adjacent cortex. In ischemic rats, the performance of a passive avoidance task was disturbed, and the pallidal GABA level detected by microdialysis decreased to about a half of control. After the graft, the deficit in the passive avoidance was partially alleviated and the GABA level recovered moderately and increased further by the infusion of an uptake blocker. The data indicate that fetal striatal cell grafts in the ischemic striatum partially restored both chemical and behavioral deficits.

Improvement of passive avoidance task after grafting of fetal striatal cell suspensions in ischemic striatum in the rat

Behavioral recovery and cell survival/growth after grafting of fetal striatal cell suspensions in the ischemic striatum of rats were investigated. Ischemia was induced by one hour intraluminal occlusion of the right middle cerebral artery under halothane anesthesia. During the ischemia rats usually manifested signs of hemiparesis and sometimes rotations. Behavioral function was measured by a passive avoidance task and radial arm maze test at 1-2 weeks and 6-7 weeks after ischemia. The size of the ischemic lesions depended on each animal, but the ischemic animals showed deficits in both passive avoidance task and radial maze test. Two weeks after ischemia, fetal striatal cells, marked with DiI, were transplanted into the ischemic striatum. The transplantation improved the ischemia-induced deficit in the passive avoidance task but not in radial maze test. Although there were variations in the size of the grafts, many DiI-positive cells with dendritic outgrowth were detected under fluorescent microscopy. Immunohistochemical study revealed that many choline acetyltransferase (ChAT) positive cells and GABA-positive cells survived in the grafts. However, striosome-matrix compartments were not evident inside the grafts. Thus, partial recoveries in both cytoarchitectural and behavioral aspects were obtained by striatal cell grafts, suggesting that neural transplantation could be a useful approach in reconstructing ischemic brain function.

Peripheral anterior inferior cerebellar artery aneurysms

Two cases of peripheral anterior inferior cerebellar artery (AICA) aneurysms are reported. The first case was a 60-year-old man who showed frequent attacks of subarachnoid hemorrhage (SAH) and hearing disturbance. His aneurysm was obliterated by trapping the AICA and his neurologic status was unchanged compared with preoperatively. The second case had SAH without cranial nerve involvement; this aneurysm was obliterated by neck clipping. He was discharged without neurologic deficit. Peripheral AICA aneurysm has already been reported in 48 cases including arteriovenous malformation-associated cases. This aneurysm may show cranial nerve involvement (seventh and eighth) without SAH as in the case of internal carotid-posterior communicating artery aneurysms. We review the clinical signs of these cases and discuss them from the point of view of anatomic variations of the AICA and internal auditory artery.