Sellar Xanthogranuloma: A Quest Based on Nine Cases Assessed with an Anterior Pituitary Provocation Test.

BACKGROUND: Xanthogranuloma is a chronic inflammatory mass characterized by cholesterol crystal deposition, which is rarely seen in the sellar region. The objective of this study is to identify the clinical features and cause of sellar xanthogranulomas. METHODS: We retrospectively analyzed manifestation, radiographic, and endocrinologic presentation in 9 patients (7 women and 2 men) whom we had previously treated. RESULTS: The patients were between 26 and 73 years of age (median, 56 years). The chief symptoms were visual symptoms in 3, polyuria in 3, headache in 4, and tiredness in 4 patients. Perimetry found visual field deficit in 6 patients. Anterior pituitary provocation tests disclosed impairment of ≥1 hormone in all patients: growth hormone in 8 patients and adrenocorticotropic hormone-cortisol axis in 8 patients. The lesions were suprasellar in 2 patients, intrasellar in 2 patients, and intrasuprasellar region in 5 patients. Three of the lesions were solid and 6 were single cystic to multicystic. Very low intensity area on T2-weighted magnetic resonance imaging was observed in 4 lesions. Postcontrast study performed in 7 lesions showed enhancement in solid parts or cyst walls. Surgical decompression improved visual disturbance in half of the patients but rarely improved hormonal deficits. Follow-up (median, 47 months) found no recurrence of the lesion. In addition to these 9 cases, we found 2 xanthogranulomatous lesions pathologically associated with ciliated epithelia, which also presented with severe hypopituitarism. CONCLUSIONS: Xanthogranuloma seems to be the last stage of the chronic inflammation affecting Rathke cleft cyst or craniopharyngioma presenting with severe anterior pituitary insufficiency.

Application of Rubber Band with Hooks on Both Ends for Vagus Nerve Stimulator Implantation.

BACKGROUND: Vagus nerve stimulation (VNS) is a valuable therapeutic option for many types of drug-resistant epilepsy. Muscle hooks and carotid endarterectomy rings have been used for cervical delamination preceding the implantation of stimulation electrodes. The attachment on both sides of a rubber band of Kamiyama-style hanging needles, as are used for scalp and dural retraction during craniotomy, yields a useful tool for VNS implantation. Here we report our experience with this method. METHODS: We present our method using a rubber band plus hooks and a review of 21 consecutive patients who underwent VNS implantation using our rubber band-plus-hooks method. RESULTS: None of the 21 patients experienced intraoperative or perioperative complications. Hooks placed in connective tissue around the common carotid artery and jugular vein raised the vagus nerve by elevating the carotid sheath. A single surgeon was able to perform all cervical manipulations under a surgical microscope. The average operation time in this series of 21 patients was 137 minutes. CONCLUSIONS: The use of hooks attached to both sides of a rubber band rendered VNS implantation safer by lifting the vagus nerve and standardizing the procedure.

Long-term outcome after endovascular treatment of cavernous sinus dural arteriovenous fistula and a literature review.

BACKGROUND: The long-term efficacy of endovascular treatment (EVT) for cavernous sinus dural arteriovenous fistulae (CS-dAVF) was assessed with a special focus on residual shunts after initial EVT. PATIENTS AND METHODS: This retrospective survey included 50 patients who had undergone EVT and were followed for 1 month or longer (median follow-up 56 months). RESULTS: Common preoperative symptoms were chemosis (78%), extra-ocular motor palsy (72%), exophthalmos (66%), and tinnitus (26%). CS-dAVF were addressed by transvenous embolization (tVE, n = 48), tVE only was used in 43 instances and tVE plus transarterial embolization (tAE) in five. Two patients underwent tAE only. Procedure-related morbidity (brainstem infarction) was recorded in one patient (2%) and transient symptom exacerbation (paradoxical worsening) in 12 patients (24%). Postoperative digital subtraction angiography showed no major retrograde shunt or cortical venous reflux in any of the 50 patients. Anterograde or minor retrograde residual shunt was observed in 17 patients (34%); three of these underwent additional tVE and four had Gamma Knife surgery. The shunt flow disappeared in all 17 patients 12.6 ± 13.4 (mean ± SD) months after initial EVT. At the latest follow-up, 65.7 ± 52.6 months after the initial operation, no shunt flow was observed in any of the 50 patients. None had remaining or newly developed chemosis or tinnitus on follow-up. The rate of persistent cavernous sinus symptoms at the latest follow-up was higher in patients with than without post-procedural paradoxical worsening (5/12, 41.7% vs. 2/38, 5.3%, p = 0.0059 by Fisher's exact test). CONCLUSIONS: Long-term follow-up showed that EVT, especially tVE, is an efficient and safe treatment for CS-dAVF. It resulted in the eventual disappearance of shunt flow. Residual shunt without major retrograde flow or cortical venous reflux can be monitored without additional treatment.

Determination of hemispheric language dominance using functional magnetic resonance imaging and the Shiritori (Japanese word chain) task in patients with epilepsy: Comparison with the Wada test.

PURPOSE: The Wada test has been the gold standard for determining hemispheric language dominance (HLD) in the presurgical evaluation of patients scheduled for neurosurgical procedures. As it poses inherent risks associated with intra-arterial catheter techniques and as it occasionally fails to indicate language dominance, an alternative reliable test is needed. We quantitatively assessed the results of functional magnetic resonance imaging (fMRI) using the Shiritori task, a Japanese word chain, to identify the threshold for correctly predicting HLD. METHODS: The subjects were 28 patients with intractable epilepsy scheduled to undergo the Wada test and focus resection. We set the region of interest (ROI) on the bilateral Brodmann areas 44 and 45 (BA 44 and 45). To compare the functional activity at both ROIs we calculated the language laterality index (LI) using the formula: [VL-VR]/[VL+VR]×100, where VL and VR indicated the number of activated voxels in the left and right ROIs, respectively. RESULTS: As 2 patients were excluded due to the lack of activation in either ROI, the final study population consisted of 26 patients. By the Wada test, HLD was left in 20, right in 3, and equivocal in 3. At a cut-off of LI+50, the predictive sensitivity and specificity for left HLD were 85% (17/20) and 100%; right HLD was predicted in a single patient (sensitivity 33.3%, specificity 100%). CONCLUSION: The fMRI using the Shiritori task showed good activation in ROI of BA 44 and 45. At a cut-off of LI+50, LI of BA 44 and 45 predicted HLD identified by the Wada test with high specificity.

Construction of 3 animal experimental models in the development of honeycomb microporous covered stents for the treatment of large wide-necked cerebral aneurysms.

The treatment of large or wide-necked cerebral aneurysms is extremely difficult, and carries a high risk of rupture, even when surgical or endovascular methods are available. We are developing novel honeycomb microporous covered stents for treating such aneurysms. In this study, 3 experimental animal models were designed and evaluated quantitatively before preclinical study. The stents were prepared using specially designed balloon-expandable stents (diameter 3.5-5.0 mm, length 16-28 mm) by dip-coating to completely cover their struts with polyurethane film (thickness 20 µm) and microprocessing to form the honeycomb pattern after expansion. (1) In an internal carotid artery canine model (n = 4), all stents mounted on the delivery catheter passed smoothly through the tortuous vessel with minimal arterial damage. (2) In an the large, wide-necked, outer-sidewall aneurysm canine model, almost all parts of the aneurysms had embolized immediately after stenting (n = 4), and histological examination at 2 months revealed neointimal formation with complete endothelialization at all stented segments and entirely organized aneurysms. (3) In a perforating artery rabbit model, all lumbar arteries remained patent (n = 3), with minimal change in the vascular flow pattern for over 1 year, even after placement of a second, overlapping stent (n = 3). At 2 months after stenting, the luminal surface was covered with complete thin neointimal formation. Excellent embolization performance of the honeycomb microporous covered stents without disturbing branching flow was confirmed at the aneurysms in this proof-of-concept study.

Effect of Revascularization on Headache Associated with Moyamoya Disease in Pediatric Patients.

Episodic headache is common in childhood moyamoya disease (MMD). The onset, mechanism, cause of headache and the effect of revascularization surgery on headache are not yet clear. We studied 10 cases of children (7 boys and 3 girls) younger than 18 years who underwent revascularization for MMD between 2009 and 2013. We evaluated frequency of headache and cerebral blood flow changes by single photon emission computed tomography brain imaging with [I123]-labeled iofetamine (IMP-SPECT) before and after surgery. Patients' ages ranged from 0 to 15 years at onset and 2 to 17 years at the time of surgery, mean age being 6.7 and 8.0 years respectively. 9 of 10 patients presented with ischemic symptoms and 8 had headache. 5 patients underwent indirect bypass and 5 underwent combined direct and indirect bypass. Cerebral blood flow improvement was obtained in 14 of the 15 cerebral hemispheres revascularized. The mean follow-up duration was 32.9 months. All the patients had good outcomes with improvement of ischemic neurological deficits. Headache improved in 7 (87.5%) of 8 patients. Headache in pediatric moyamoya disease is associated with change in cerebral hemodynamics. Revascularization including combined direct bypass and indirect techniques may be required to reduce headache in patients with MMD.

Improvement in treatment results of glioblastoma over the last three decades and beneficial factors.

BACKGROUND: The purpose of this study is to elucidate the trend of glioblastoma outcome and scrutinize the factors contributing to better outcome over three decades. METHODS: Survival time and the influencing factors were retrospectively analyzed in 223 newly diagnosed primary glioblastoma patients during 1980-2010. Appraised factors included age, sex, tumor site, year of surgery, extent of resections, use of surgery supporting system, Karnofsky Performance Status (KPS), chemotherapy, conventional external beam radiotherapy (EBRT), and CyberKnife stereotactic radiotherapy (CK-SRT) use. RESULTS: The median survival time (MST) in all patients was 13.6 months. The MSTs for 4 periods were 9.8 (1980-1990), 13.7 (1991-2000), 12.9 (2001-2005), and 15.8 months (2006-2010), respectively (p=0.0047). Total resection, subtotal resection, partial resection, and biopsy had MSTs of 31.8, 13.9, 11.4, and 7.0 months, respectively (p<0.0001). Regarding chemotherapy, MSTs of the temozolomide base group and nimustine hydrochloride (ACNU) base group were 16.9 and 14.6 months, respectively, whereas the MST of patients without chemotherapy was only 9.8 months (p<0.0001). The MSTs for 40-Gy EBRT plus CK-SRT and 60-Gy EBRT were 19.1 and 10.7 months, respectively (p<0.0001). But in sub-selected patients, treated during 2001-2010, whose resection rate was total resection or subtotal resection, EBRT was completed and postoperative KPS was greater than or equal to 70, the MST with and without CK-SRT was 26.6 and 18.3 months, respectively (p=0.1529). According to the Cox proportional hazards model, degree of resection, KPS, ACNU use, temozolomide use, bevacizumab use, EBRT dose, and CK-SRT use were good prognostic factors. Use of neuronavigation and use of intraoperative magnetic resonance imaging were related to higher resection rate, but not determined as prognostic factors. CONCLUSIONS: We observed a gradual improvement in glioblastoma outcome, presumably because of improvements in therapeutic modalities for surgery, anticancer agents, and radiation, but the efficacy of CK-SRT remains unclear.

Intraoperative continuous monitoring of facial motor evoked potentials in acoustic neuroma surgery.

The preservation of facial nerve function is one of the primary objectives in acoustic neuroma surgery. We detail our method of continuous intraoperative facial motor evoked potential (MEP) monitoring and present criteria for the preservation of facial nerve function to avoid postoperative facial nerve palsy. Our study population was comprised of 15 patients who did not (group 1), and 20 who did (group 2) undergo facial MEP monitoring during surgery to remove acoustic neuromas. In group 2, we continuously stimulated the facial motor cortex at 5- or 10-s intervals throughout surgery. Electromyograms (EMGs) were recorded from the contralateral orbicularis oculi- and orbicularis oris muscles. Optimal anode and cathode placement was at the facial motor cortex and the vertex, respectively. Postoperative facial palsy occurred in 8 of the 15 group 1 patients; in 2 it improved to grade II at 6 months after the operation. Of the 20 group 2 patients, 7 suffered postoperative facial palsy. At 6 months after the operation, their facial nerve function was normal. At the end of the operation, the ratio of the amplitude of the supramaximal EMG to the amplitude at the dural opening was 39.6 % in patients with- and 94.3 % in patients without transient postoperative facial palsy. Continuous facial MEP monitoring not only alerts to surgical invasion of the facial nerves but also helps to predict postoperative facial nerve function. To preserve a minimum amplitude ratio of 50 %, even transient postoperative facial palsy must be avoided. MEP monitoring is an additional useful modality for facial nerve monitoring during acoustic neuroma surgery.

Immunoreactivity of Wnt5a, Fzd2, Fzd6, and Ryk in glioblastoma: evaluative methodology for DAB chromogenic immunostaining.

The aim of this study was to determine the influence of Wnt5a and its receptors on the survival of glioblastoma patients and to determine reliable evaluation methods for immunohistochemistry. Diagnostic specimens from 41 histopathologically confirmed primary glioblastoma patients whose Gd-enhanced tumors had been totally removed were immunohistochemically stained for Wnt5a, Fzd2, Fzd6, and Ryk. The immunoreactivity was evaluated using the following methods: (A) grayscale optical density after color deconvolution, (B) percentage of stained cells, (C) density of stained cells, (D) staining amount (multiplication product of B and C), and (E) staining rank. The data sets of A to E were statistically evaluated by correlation matrix analysis and regression analysis. The influence of the expression of the markers on survival was analyzed using a proportional hazard model. The results of color deconvolution (A) were well correlated with the results of the staining rank (E). In the semiquantitative results (B, C, and D), the staining amount (D) tended to show a better correlation with results of color deconvolution (A). Among all data sets, color deconvolution (A) demonstrated the most preferable fit in a proportional hazard model, and the expression of Fzd2 and Fzd6 was associated with poor prognosis in glioblastoma patients.

Electrophysiological mapping of the temporal branch of the facial nerve.

BACKGROUND: Minimized frontal and frontolateral approaches have been proposed for the clipping of aneurysms and for removal of deep-seated supra- and parasellar lesions. To avoid postoperative facial nerve palsy, anatomical studies have been conducted; however, only one electrophysiological investigation has been reported. We studied the course of the facial nerve in the temporal region and identify the optimal pterional keyhole craniotomy from the perspective of facial nerve protection. MATERIALS AND METHODS: We stimulated the temporal branch of the facial nerve in nine healthy volunteers and identified its course electrophysiologically. Electromyographic (EMG) responses were recorded from the superior orbicularis oculi, corrugator, and frontal muscles. The course of the temporal branch of the facial nerve was identified by tracking the stimulation points that elicited the best EMG responses. RESULTS AND CONCLUSION: The distances from the tragus to the canthus, the tragus to the point where the facial nerve crosses over the zygomatic arch, the tragus to the first nerve bifurcation, the tragus to the second nerve bifurcation, and from the orbit to the middle rami were 80.8 ± 1.8 mm, 40.2 ± 1.6 mm, 58.1 ± 2.8 mm, 79.1 ± 3.4 mm, and 16.4 ± 0.9 mm, respectively. We found that the temporal branch of the facial nerve innervates each muscle in posterior-anterior direction. Based on these results, we prefer the pterional keyhole approach and incise the skin at a site posterior to the temporal branch of the facial nerve.

Effect of thrombin concentration on the adhesion strength and clinical application of fibrin glue-soaked sponge.

Fibrin glue-soaked gelatin sponge (FGGS) has been used for tissue sealing in neurosurgical practice, but too rapid clotting of fibrin glue occasionally prevents good fixation of FGGS. Dilution of thrombin may provide adequate manipulation time between mixing fibrinogen and thrombin on gelatin sponge and application into the tissue defects. The present study characterized the effect of thrombin dilution on the adhesion strength of FGGS and retrospectively assessed the clinical usage of the dilution for filling dead space or sealing arachnoid defect in 255 cases who underwent transsphenoidal surgery for the last 66 months. FGGS was prepared using three different concentrations of thrombin: 250 (standard), 50 (1:5 dilution), and 25 (1:10 dilution) units/ml, and incubated for three different periods (5, 20, and 60 seconds). FGGSs were applied over two adjacently positioned porcine skins placed on two metallic plates. The adhesion strength was evaluated by measuring maximum tensile strength during pulling out the sliding plate at a constant rate of displacement. The maximum adhesion strength was greater for FGGS with 1:10 diluted thrombin solution than for FGGS prepared with higher concentrations (p < 0.05). Adhesion strength did not decay for 20 seconds after the mixture. Only four of 255 cases (1.6%) required second reconstruction of sella floor due to the cerebrospinal fluid leakage. FGGS prepared with diluted thrombin solution can provide adequate adhesion strength for clinical use.

Immunohistochemical expression of thrombomodulin in vestibular schwannoma.

Many vestibular schwannomas (VS) manifest intratumoral microhemorrhages whose underlying mechanisms are not fully understood. Thrombomodulin (TM) is an endothelial anticoagulant cofactor that promotes the thrombin-mediated formation of activated protein C that inhibits thrombus formation. We investigated the existence of TM in VS and its potential role in the development of microhemorrhages. We used immunohistochemical staining to study the expression of TM in tissues derived from 25 patients with VS. Hemosiderin deposition was examined by Berlin blue staining and compared with the expression of TM. Vascular endothelial cells in all 25 VS tissues expressed TM. The TM-positive vessel ratio, calculated by dividing the number of TM-positive by the number of CD34-positive lumens, was significantly higher in hemosiderin-laden than hemosiderin-negative tissues (0.71 ± 0.17 vs. 0.53 ± 0.31, p = 0.049, Mann-Whitney U test). Our findings suggest a close relationship between the expression of TM and microhemorrhage in VS.

Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms.

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals. Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n = 5) followed by the postmeatal (n = 3) and premeatal segment (n = 1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery. We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3 months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75 %). We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.

TLR4, IL-6, IL-18, MyD88 and HMGB1 are highly expressed in intracranial inflammatory lesions and the IgG4/IgG ratio correlates with TLR4 and IL-6.

We determined distribution of plasma cells and IgG4/IgG index and factors associated with the index in intracranial inflammatory lesions. Specimens of nine patients were analyzed immunohistochemically using antibodies against CD45, CD68, CD3, CD4, CD8, CD20, CD138, lambda chain, kappa chain, IgG, IgG4, IL-1α, IL-6, IL-18, toll-like receptor (TLR) 2, TLR4, high-mobility group box 1 (HMGB1), tumor necrosis factor-alpha (TNF-α), myeloid differentiation factor 88 (MyD88), and anaplastic lymphoma kinase (ALK). The relationship between all the factors was assessed using Spearman's rank correlation coefficient (ρ). Negative ALK staining was observed in all the patients. Plasma cells were detected in eight patients with varying degrees. The highest number of neutrophils, but no plasma cells, was observed in a patient with the shortest history of inflammation. IgG4/IgG index was independent of the number of plasma cells. The index was relatively highly correlated with IL-6 (ρ = 0.7271) and TLR4 expression (ρ = 0.7246). IL-6 expression was highly correlated with TLR4 expression (ρ = 0.8042). IL-18 was maximally expressed in all the patients. TLR4 expression was strong, but TRL2 expression was weak. Positive HMGB1 staining was observed in all the patients, predominantly in the nuclei, but also in the cytoplasm in four patients. The cytoplasmic expression strongly correlated with IL-1α expression (ρ = 0.9583). The cytoplasmic colocalization of HMGB1 and IL-1α was histologically confirmed in cells with collapsing nuclei by the double-staining method. The IgG4/IgG indexes varied case by case. IL-6 and TLR4 expressions may influence IgG4/IgG index. The nuclei of cells with both IL-1α and HMGB1 expressions in the cytoplasm collapse in the cell death stage. The cooperative high expression of TLR4, IL-6, IL-18, MyD88 and HMGB1 suggest their critical roles in the inflammation circuit.

Neuroprotective effect of levetiracetam on hippocampal sclerosis-like change in spontaneously epileptic rats.

The spontaneously epileptic rat (SER) begins to exhibit both tonic convulsions and absence seizures from 6 weeks of age and SERs have stable seizures after 10 weeks of age. Low-dose administrations of levetiracetam (LEV) for 4- to 5-weeks-old SERs which did not show spontaneous seizures reduced both seizures 5 weeks after termination of administration. The hippocampus of SER exhibited decreased CA3 neurons, sprouting of mossy fibers, and hyperexpression of the brain-derived neurotrophic factor (BDNF). We attempted prophylactic LEV administrations in preseizure-manifesting SERs to evaluate if such a treatment regimen would protect the hippocampal sclerosis-like changes observed in SERs. The osmotic mini-pump administered LEV dissolved in saline to 4-weeks-old SERs for 4 weeks at 2.5 µl/h. LEV was administered at 420 mg/ml for 4 weeks in Group A. In Group B, LEV was given at 420 mg/ml for the first 2 weeks followed by doubling the dosage (840 mg/ml) in the following 2 weeks. LEV administrations in preseizure-manifesting SERs reduced the decrease of CA3 neurons and mossy fibers sprouting at 10-11 weeks of age in both group A and B. LEV attenuated BDNF expression in inner molecular layers of the dentate gyrus, striatum radiatum, and CA3 in 10- to 11- and 14- to 15-weeks-old SERs. In group B, LEV decreased BDNF expression in hilus and CA1 of 10- to 11- weeks-old SER. The present results suggest that prophylactic treatment with LEV in preseizure-manifesting SERs inhibits hippocampal sclerosis-like neuronal degeneration and/or regeneration.

Pineal mixed germ cell tumor with a synchronous sellar lesion in the sixth decade.

Intracranial germ cell tumors (GCTs) typically affect children and adolescents. We here report on a 59-year-old male patient presenting with diplopia, polydipsia and polyuria. On clinical examination, slight restriction of the upward gaze was seen on the left side. Computed tomography demonstrated calcifications in the pineal region and enhanced neurohypophysis. Magnetic resonance imaging displayed a heterogeneous pineal mass of 3-cm diameter, which was multicystic with an enhanced cyst wall, and also swelling of the pituitary stalk. The pineal lesion of the tumor, which included calcifications and keratinaceous components, was totally excised using an occipital transtentorial approach. Histopathological examination showed it to be a mixed GCT with germinoma and mature teratoma components. Postoperative chemoradiotherapy provided complete disappearance of the suprasellar lesion. To our knowledge, this is the first case of mixed bifocal GCT in an older adult reported in the literature, although a few cases of tumors with a single histological component have been reported. Hence, our case further underlines the possibility of the occurrence of GCTs in older adults and advocates the consideration of GCTs in the differential diagnosis of such cases for appropriate management.

Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms.

Aneurysms located at the distal portion of the posterior inferior cerebellar artery (PICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of 30 distal PICA aneurysms in 28 patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals. Our series includes 20 women and eight men. Of their 30 aneurysms, 24 were ruptured, and six were unruptured; there were 27 saccular and two fusiform aneurysms; one was dissecting. Their location was at the anterior-medullary (n = 4), lateral-medullary (n = 9), tonsillomedullary (n = 7), telovelotonsillar (n = 6), and cortical (n = 4) segment of the PICA. In 18 patients, angiographic features suggested hemodynamic stress including an absent contralateral PICA or ipsilateral anterior inferior cerebellar artery, termination of the vertebral artery (VA) at the PICA, and hyperplasia or occlusion of the contralateral VA. As three patients died before surgery, 27 aneurysms in 25 patients were surgically treated. Of these, 6 were unruptured aneurysms; 20 were clipped via midline or lateral suboccipital craniotomy, and 5 were embolized with Guglielmi coils; in one, the PICA flow was reconstructed by OA-PICA anastomosis, and in the other one, the PICA was resected. Of the 25 surgically treated patients, 22 (88%) had good outcomes. The predominant contributor to the development of distal PICA aneurysms is thought to be increased hemodynamic stress attributable to anomalies in the PICA and related posterior circulation. Both direct clipping and coil embolization yielded favorable outcomes in our series. However, considering the difficulties that may be encountered at direct clipping in the acute stage and the availability of advanced techniques and instrumentation, aneurysmal coiling is now the first option to address these aneurysms.

Hippocampal cell loss and propagation of abnormal discharges accompanied with the expression of tonic convulsion in the spontaneously epileptic rat.

Spontaneously epileptic rats (SER) are double mutants with both tonic convulsion and absence-like seizures from the age of 8 weeks. Hippocampal CA3 neurons in SER display a long-lasting depolarizing shift accompanied by repetitive firing (attributed to abnormalities of the Ca(2+) channels) with a single stimulation of the mossy fibers. In the present investigation, we examined if the seizure discharges of SER were correlated with the hippocampal abnormality of SER using electrophysiological and histological methods. In CA1 neurons of seizure-susceptible mature SER, higher-voltage (<8-11 V) stimulations induced a long depolarization shift (in 25% of neurons) with repetitive firing (in 12.5% of neurons). However, the tremor rat, one of the parent strains of SER, did not exhibit such abnormal firing in the CA3 region of the hippocampus. The number of CA3 neurons in SER was significantly (p<0.01) lower than that in tremor rats and Wistar rats, although no significant difference was established in the hilus. Sprouting of mossy fiber was observed in the dentate of mature SER; however, negligible staining was spotted in the dentate of both mature tremor and Wistar rats. Interestingly, expression of the brain-derived neurotrophic factor was higher in the hilus, CA3, and granular cell layer of dentate gyrus in SER than normal Wistar rats. The expression levels of TUNEL, bax, and Caspase-3 did not show significant changes between the SER and Wistar rats. SER exhibited hippocampal sclerosis-like changes which did not have enough potential for epileptogenesis. Repetitive tonic seizures and vulnerable CA3 neurons of SER could be involved in the induction of sclerosis-like changes in the hippocampus.

Use of a guide wire system to insert guiding catheters.

In patients with severe arteriosclerosis or anatomical variations such as a bovine arch, the insertion of a guiding catheter for carotid artery stenting is difficult. The authors use a guide wire system as an anchor and advance the guiding catheter to an area proximal to the stenotic structure. This method is useful and safer than others for carotid artery stenting.

Xanthogranuloma in the suprasellar region.

A 26-year-old man presented with a xanthogranuloma located exclusively in the suprasellar region manifesting as general fatigue, bitemporal hemianopsia, and polyuria. Endocrinological examination disclosed severe hypopituitarism. Magnetic resonance imaging demonstrated a clearly defined suprasellar mass that was heterogeneously enhanced after gadolinium administration and was markedly hypointense on T(2)-weighted images. The tumor was subtotally removed under a preoperative diagnosis of craniopharyngioma. Histological examination found fibrous tissue with abundant cholesterol clefts, multinucleated giant cells, and hemosiderin deposits, but no epithelial cells. Xanthogranulomas of the sellar region are reported to be predominantly located in the sella turcica, but should be included in the differential diagnosis even in cases of suprasellar mass lesions.