Shinji Iwata

Endothelial nitric oxide synthase expression in tumor vasculature is correlated with malignancy in human supratentorial astrocytic tumors

OBJECTIVE Endothelial nitric oxide synthase (eNOS) may play an important role in the regulation of tumor blood flow and vascular permeability. However, there have been no reports describing alterations of eNOS expression in relation to malignant progression in human astrocytic tumors. We immunohistochemically studied the relationship between eNOS expression in tumor vasculature and malignancy in supratentorial astrocytic tumors. METHODS Tissue samples were obtained from 12 patients with low-grade astrocytomas, 10 with anaplastic astrocytomas, and 17 with glioblastomas. Normal brain tissue samples were obtained from four patients with other brain diseases. Immunohistochemical staining was performed using the avidin-biotin complex method, with polyclonal anti-eNOS antibody, and the levels of eNOS expression in endothelial cells were evaluated as slight, moderate, or intense on the basis of eNOS immunoreactivity. The proliferative potential was assessed as the MIB-1 staining index for tumor cells. RESULTS The expression of eNOS was slight in all specimens of normal brain tissue, slight in 7 and moderate in 5 specimens of low-grade astrocytoma, slight in 2, moderate in 6, and intense in 2 specimens of anaplastic astrocytoma, and moderate in 5 and intense in 12 specimens of glioblastoma. The MIB-1 staining index (mean+/-standard deviation) was 0.2+/-0.2% for normal specimens, 1.8+/-0.6% for low-grade astrocytomas, 9.6+/-6.9% for anaplastic astrocytomas, and 18.5+/-7.7% for glioblastomas. The MIB-1 staining indices for slight, moderate, and intense eNOS expression were 2.0+/-2.3%, 10.8+/-9.8%, and 16.9+/-7.7%, respectively. CONCLUSION Expression of eNOS in tumor vessels was significantly correlated with histological grade and proliferative potential. These findings suggest that astrocytic tumor vessels possess higher activity for nitric oxide production than do normal vessels.

Downregulation of laminin α4 chain expression inhibits glioma invasion in vitro and in vivo

The laminin family is a structural constituent of the extracellular matrix that plays an essential role in promoting the motility of infiltrative tumor cells. We investigated the role of laminin α4 chain, a subset of laminin‐8, ‐9 and ‐14, in the motile and invasive activities of human glioma cells. All malignant glioma cell lines examined expressed more mRNA for the laminin α4 and β1 chains than for the β2 chain, indicating that these cells predominantly express the laminin‐8 isoform. Introducing an antisense oligonucleotide for laminin α4 chain (AS‐Ln‐α4) into the glioma cells resulted in downregulation of laminin α4 expression. AS‐Ln‐α4 also significantly suppressed glioma cell adhesion and migration. Furthermore, invasiveness was significantly reduced in cells transfected with AS‐Ln‐α4 compared to those transfected with the sense oligonucleotide (S‐Ln‐α4). Indeed, when glioma spheroids were implanted into rat brain slices, AS‐Ln‐α4‐transfected cells failed to invade surrounding normal brain tissues. In addition, intracerebral injection of glioma cells transfected with AS‐Ln‐α4 into nude mice resulted in the formation of a noninvasive tumor, whereas injection of cells transfected with S‐Ln‐α4 resulted in diffuse invasion of brain tissue. These results suggest that mainly laminin‐8 is essential for the invasive activity of human glioma cells; thus, a novel therapeutic strategy could target this molecule to treat patients with malignant glioma.

Downregulation of laminin alpha4 chain expression inhibits glioma invasion in vitro and in vivo.

The laminin family is a structural constituent of the extracellular matrix that plays an essential role in promoting the motility of infiltrative tumor cells. We investigated the role of laminin α4 chain, a subset of laminin‐8, ‐9 and ‐14, in the motile and invasive activities of human glioma cells. All malignant glioma cell lines examined expressed more mRNA for the laminin α4 and β1 chains than for the β2 chain, indicating that these cells predominantly express the laminin‐8 isoform. Introducing an antisense oligonucleotide for laminin α4 chain (AS‐Ln‐α4) into the glioma cells resulted in downregulation of laminin α4 expression. AS‐Ln‐α4 also significantly suppressed glioma cell adhesion and migration. Furthermore, invasiveness was significantly reduced in cells transfected with AS‐Ln‐α4 compared to those transfected with the sense oligonucleotide (S‐Ln‐α4). Indeed, when glioma spheroids were implanted into rat brain slices, AS‐Ln‐α4‐transfected cells failed to invade surrounding normal brain tissues. In addition, intracerebral injection of glioma cells transfected with AS‐Ln‐α4 into nude mice resulted in the formation of a noninvasive tumor, whereas injection of cells transfected with S‐Ln‐α4 resulted in diffuse invasion of brain tissue. These results suggest that mainly laminin‐8 is essential for the invasive activity of human glioma cells; thus, a novel therapeutic strategy could target this molecule to treat patients with malignant glioma.

Usefulness of endoscope-assisted microsurgery for removal of vestibular schwannomas.

The usefulness of endoscope-assisted microsurgical removal of vestibular schwannomas in the internal auditory canal (IAC) was evaluated. Microsurgical removal using the endoscope was done in 28 procedures and microsurgical removal without an endoscope was done in 43 procedures. A retrosigmoid approach was used. The tumor location in the IAC was classified as grade 1 (located up to the mid-portion), 2, 3, or 4 (located up to the fundus with bony destruction) according to the tumor extent, and residual tumor in the IAC was evaluated as grade A (remnant tumor was not observed), B, C, or D (remnant tumor was observed over the mid-portion) according to the extent of remnant tumor. The residual tumor in the IAC was less in the endoscope-assisted group than in the microsurgery group. There was a significant difference only in grade 2, that is, tumor located beyond the mid-portion of the IAC. There was no significant difference in the results of preservation of useful hearing, facial nerve function, and tumor recurrence between the two groups. The benefit of endoscope-assistance microsurgery was shown for those patients whose tumors extended beyond the mid-portion of the IAC but did not reach the fundus.

Oct-3/4 promotes tumor angiogenesis through VEGF production in glioblastoma

Accumulating evidence shows that the expression level of Oct-3/4, a self-renewal regulator in stem cells, is positively correlated with the progression of various solid tumors. However, little is known regarding the influence of Oct-3/4 in the tumor angiogenesis of glioblastomas. In the present study, we subcutaneously transplanted Oct-3/4-overexpressing human glioblastoma U251 (U251/EGFP-Oct-3/4) cells into the right thighs of nude mice to evaluate the roles of Oct-3/4 in the tumor angiogenesis. Both tumor size and the number of large vessels growing in the tumor were markedly increased. In an in vitro model of angiogenesis, the conditioned media from U251/EGFP-Oct-3/4 cells significantly accelerated capillary-like tube formation compared with that of U251/EGFP cells. In comparison with U251/EGFP cells, U251/EGFP-Oct-3/4 cells had markedly elevated the expression of vascular endothelial growth factor mRNA under the control of hypoxia-inducible factor (HIF) 1α. In U251/EGFP-Oct-3/4 cells, enhanced protein expression and nuclear translocation of HIF1α were observed. Furthermore, we demonstrated that the involvement of AKT, an oncogenic signaling molecule, in the Oct-3/4 induced upregulation of HIF1α protein. Our findings suggest that Oct-3/4-expressing glioblastoma cells have the ability to adapt to low-oxygen environments within tumor masses by promoting tumor angiogenesis through AKT-HIF1 pathway.

Usefulness of cervical computed tomography and magnetic resonance imaging for rapid diagnosis of crowned dens syndrome: A case report and review of the literature

Highlights • We report a patient with crowned dens syndrome dramatically improved following treatment with nonsteroidal anti-inflammatory medication.• This condition should be considered in the differential diagnosis of a possible etiology for fever, headache and cervical pain of unknown origin.• The rapid diagnosis of crowned dense syndrome using CT and MRI can prevent invasive, expensive and useless investigations.• It was very interesting that the soft tissue surrounding the odontoid process was hyperintense on MR T2-weighted imaging with fat suppression.• This is the first report of making reference to MRI findings of crowned dens syndrome.

Importance of perioperative management for emergency carotid artery stenting within 24 h after intravenous thrombolysis for acute ischemic stroke: Case report

Highlights • We report a patient treated successfully via endovascular surgery within 24 h after intravenous thrombolysis using recombinant tissue plasminogen activator for acute cervical internal carotid artery occlusion.• Emergency carotid artery stenting for the acute internal carotid artery occlusion may be considered a safe procedure in preventing early stroke recurrence in selected patients.• When trying to perform emergency carotid artery stenting within 24 h after intravenous recombinant tissue plasminogen activator administration, several issues require attention, such as the decisions regarding the type of stent and embolic protection device, the selection of antiplatelet therapy and the methods of preventing hyper perfusion syndrome.• We administered aspirin and clopidogrel for the prevention of subacute thrombosis, and we used dexmedetomidine for preventing hyperperfusion syndrome, so that we also obtained a good result.

Identification of characteristic features of pineal germinoma that enhance accuracy of preoperative differentiation in pineal region tumors: its significance on optimum surgical treatment

The aim of the study is to identify characteristic features of pineal germinoma that enhance preoperative accuracy in differentiating germinoma from other pineal region tumors. Twenty-one consecutive patients with pineal region tumors were enrolled. In all patients, tumor resection was performed to verify the histology. Clinical records including upward gaze palsy of Parinaud’s syndrome and neuroimaging were analyzed. In addition, we evaluated the relationship between magnetic resonance imaging (MRI) findings and tumor progression patterns in pineal germinoma. Among 21 patients, 15 patients were diagnosed with germ cell tumor, 4 with pineal parenchymal cell tumor, and 2 with meningioma. Upward gaze palsy was seen in 11 patients; nine had pure germinomas and two had mixed germ cell tumors. These tumors occupied the pineal region with extension to the area of the mesodiencephalic junction (MDJ) and the bi-epithalamic area between the bilateral pulvinar and the third ventricle. Tumor involvement of the former area could cause upward gaze palsy by insulting the rostral interstitial nucleus of the medial longitudinal fasciculus located in the MDJ area. Tumor invasion into the latter area is commonly seen as a cardioid-shaped tumor as the tumor image on the axial MRI view. Upward gaze palsy and a cardioid-shaped tumor image on the axial MRI views were demonstrated to be specific features of pineal pure germinoma. It is suggested that combination of both features may become useful tools to preoperatively differentiate germinoma from other pineal tumors, resulting in achievement of the optimum treatment of pineal region tumors.

[A Case of ECA-MCA Double Anastomoses for Hemorrhagic Type of Twig-Like MCA].

Herein, we describe the case of a superficial temporal artery(STA)- and occipital artery (OA)-middle cerebral artery (MCA) double anastomoses that we performed to treat a hemorrhagic twig-like MCA. A 55-year-old man presented to our hospital for investigation of an incidentally identified left MCA occlusion. Left cerebral angiography revealed a twig-like MCA. The (123)I-IMP-single photon emission computed tomography( SPECT) demonstrated no reduction in the cerebral blood flow (CBF), so the patient was initially observed with no treatment. Three months later, he was readmitted with a disturbance of consciousness. The cranial computed tomography revealed a subcortical hemorrhage in the left frontotemporal region and a subdural hematoma. The hematoma was removed via emergency craniotomy. The abnormal vessels were identified and resected, but the parietal branch of the STA was damaged during the skin incision. The histological examination did not reveal the marked fibrous thickening of the intima or wavy internal elastic lamina typically seen with Moyamoya disease. Six months after the initial surgery, a STA-MCA bypass surgery was planned to prevent a future hemorrhage by reducing the hemodynamic overload of the twig-like MCA and improving the cerebral ischemia in the MCA territory that was detected on the preoperative SPECT. However, the parietal branch of the left STA had been injured during the first operation, so we performed a double anastomoses to the MCA using the frontal branch of the STA and the OA. The patients postoperative course was uneventful and he was discharged 2 weeks after surgery. The follow-up study performed 1 year postoperatively demonstrated no evidence of cerebral infarction and revealed an improvement in the resting CBF and vascular reactivity in the left cerebral hemisphere. No subsequent cerebrovascular events have occurred in this patient during the 7 years since the double anastomoses surgery. Direct bypass for flow conversion from the internal carotid artery to the external carotid artery can be an indispensable treatment for patients with a hemorrhagic twig-like MCA.

[Hemorrhagic Adult Unilateral Moyamoya Disease with Multiple Unruptured Intracranial Aneurysms: A Case Report].

Adult unilateral moyamoya disease with intracranial aneurysm is frequently reported in the literature, but there is much variation in its treatment. In this case report, we describe the time course and treatment regimen of a patient with moyamoya disease and review the literature regarding moyamoya disease with intracranial aneurysm. A 64-year-old man had untreated intracranial aneurysm and unilateral moyamoya disease for 10 years. He presented with sudden-onset right hemiparesis and aphasia due to a subcortical hemorrhage. He was admitted to the local neurosurgical unit, and upon resolution of symptoms, he was admitted to our hospital. A cerebral angiogram revealed the champagne bottleneck sign of the left carotid artery and obliteration of the top of the left intracranial carotid artery with a moyamoya phenomenon. Two unruptured intracranial aneurysms were identified in the anterior communicating artery(Acom A) and the right intracranial carotid artery(C3). We performed superficial temporal artery-middle cerebral artery anastomosis followed by aneurysmal neck clipping of the Acom A aneurysm. Postoperative imaging showed no new ischemic damage and improved cerebral blood flow. Although the patient experienced temporal worsening of aphasia, his function recovered a few months later and he was able to resume his normal daily life activities. The combination of direct bypass surgery and aneurysmal neck clipping might be a therapeutic option for hemorrhagic unilateral moyamoya disease with unruptured intracranial aneurysm.