Motohiro Nomura

Advanced Glycation End Products-driven Angiogenesis in Vitro INDUCTION OF THE GROWTH AND TUBE FORMATION OF HUMAN MICROVASCULAR ENDOTHELIAL CELLS THROUGH AUTOCRINE VASCULAR ENDOTHELIAL GROWTH FACTOR

This study was undertaken to determine whether and how advanced glycation end products (AGE), senescent macroproteins accumulated in various tissues under hyperglycemic states, cause angiogenesis, the principal vascular derangement in diabetic microangiopathy. We first prepared AGE-bovine serum albumin (BSA) and anti-AGE antiserum using AGE-RNase A. Then AGE-BSA was administered to human skin microvascular endothelial cells in culture, and their growth was examined. The AGE-BSA, but not nonglycated BSA, was found to induce a statistically significant increase in the number of viable endothelial cells as well as their synthesis of DNA. The increase in DNA synthesis by AGE-BSA was abolished by anti-AGE antibodies. AGE-BSA also stimulated the tube formation of endothelial cells on Matrigel. We obtained the following evidence that it is vascular endothelial growth factor (VEGF) that mainly mediates the angiogenic activities of AGE. (1) Quantitative reverse transcription-polymerase chain reaction analysis of poly(A)+ RNA from microvascular endothelial cells revealed that AGE-BSA up-regulated the levels of mRNAs for the secretory forms of VEGF in time- and dose-dependent manners, while endothelial cell expression of the genes encoding the two VEGF receptors, kinase insert domain-containing receptor and fms-like tyrosine kinase 1, remained unchanged by the AGE treatment. Immunoprecipitation analysis revealed that AGE-BSA did increase de novo synthesis of VEGF. (2) Monoclonal antibody against human VEGF completely neutralized both the AGE-induced DNA synthesis and tube formation of the endothelial cells. The results suggest that AGE can elicit angiogenesis through the induction of autocrine vascular VEGF, thereby playing an active part in the development and progression of diabetic microangiopathies.

Induction of various blood-brain barrier properties in non-neural endothelial cells by close apposition to co-cultured astrocytes

Vascular endothelial cells (EC) exhibit organ‐to‐organ heterogeneity in their functions and morphologies. In particular, brain capillary EC have unique characteristics exemplified by the blood‐brain barrier (BBB). The formation and the maintenance of BBB have been ascribed to EC responses to inductive signal(s) or factor(s) from astrocytes that encircle microvessels in the central nervous system. These EC responses were demonstrated in numerous in vivo studies, exemplified by those of Janzer and Raff (Nature 325:253, 1987) and Tout et al. (Neuroscience 55:291, 1993) showing that transplanted astrocytes induced BBB properties in non‐neural vascular EC. In this study, we constructed a heterologous co‐culture system, in which rat fetal brain astrocytes were cultivated on one surface of a porous membrane and human umbilical vein EC on the opposite surface. Electron microscopic examination revealed that astrocytes passed their endfeet through the pores, making contact with EC. In this system, γ‐glutamyltranspeptidase (γ‐GTP) activity in EC was found to be significantly increased by contacting astrocytes in a density‐and time‐dependent manner, but not when the astrocyte feeder layer was apart from EC or replaced by COS cells; astrocyte‐derived extracellular matrix partially activated γ‐GTP. mRNAs for some of the representative BBB markers, including transferrin receptor, P‐glycoprotein, brain‐type glucose transporter(GLUT‐1), and γ‐GTP were also demonstrated by reverse transcription‐polymerase chain reaction to be upregulated in EC co‐cultured with astrocytes. Astrocyte inductions of close membrane apposition resembling a zonula occludens and of an increase in the content of mitochondria in EC were also noted in electron micrographs. Furthermore, an increased barrier activity against inulin was conferred on EC when they were lined with astrocytes. The results obtained with this heterologous co‐culture system thus indicate that through contact with their feet, astrocytes are capable of transdifferentiating non‐neural EC into the brain type, endowing them with the BBB properties. Glia 19:13–26, 1997

Placenta growth factor (PlGF) mRNA expression in brain tumors

To investigate the relationship between placenta growth factor (PlGF) and brain tumor angiogenesis, we screened 36 primary and 3 metastatic brain tumors. We examined the expression of PlGF mRNA with respect to vasculature of various tumors which was determined by preoperative angiography. The expression of genes of the other angiogenic factors, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) was also tested, and compared to that of PlGF. The primary tumors consisted of 16 meningiomas, 7 gliomas, 7 schwannomas, 4 pituitary adenomas, 1 germinoma, and 1 choriocarcinoma. Using a quantitative reverse transcription-polymerase chain reaction, the mRNA for PlGF149 and PlGF170 were detected in 25 out of 39 (64.1%) brain tumors. In primary brain tumors, PlGF mRNA was expressed in all the hypervascular tumors, but only in 5 of 16 hypovascular tumors (31.3%). None of the 3 metastatic hypervascular tumors expressed PlGF mRNA. The VEGF and bFGF mRNA expression was both detected in 87.2% of the tumors examined. We conducted hypoxic experiments with cultured U-251MG human glioma cells to determine the mechanism of PlGF gene regulation. As the atmospheric oxygen concentration was decreased, the PlGF mRNA level in the U-251MG cells was markedly increased. These results suggest that PlGF may contribute to the pathogenesis of brain tumor angiogenesis.

Significance of Volume Embolization Ratio as a Predictor of Recanalization on Endovascular Treatment of Cerebral Aneurysms with Guglielmi Detachable Coils

The purposes of this study are, firstly, to define the relationship between volume embolization ratio (VER) and degree of angiographical occlusion in endovascular treatment with Guglielmi detachable coils, and secondly, to examine influences of neck and dome sizes of aneurysms on the VER and the angiographical treatment result, and thirdly, to determine the relationship between the VER and the recanalization of coiled aneurysms. Fifty-two aneurysms in 46 patients were examined. VER ranged 8.1–31.9% (mean 18.5%). The mean VERs of each categories based on angiographical treatment results were 23.1% in complete occlusion, 16.1% in neck remnant and 12.2% in incomplete occlusion, respectively. The VER correlated significantly with both neck and dome size, while the angiographical treatment result was only affected by neck size. Five aneurysms showed aneurysmal recanalization among followed-up 41 aneurysms. All recanalized aneurysms were large, and their VERs were in range of 10.4–17.6%. Measurement of VER is useful to estimate the degree of occlusion objectively and to predict the aneurysmal recanalization. A small aneurysms with a small neck is relatively easy to achieve high VER and angiographical complete occlusion, with the consequence of less recanalization. On the other hand, a large aneurysm is liable to recanalize due to low VER, even if there was little filling of contrast medium in the aneurysmal cavity.

Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland.

Cervical spinal cord infarction after surgery for a pineal region choriocarcinoma in the sitting position: case report.

OBJECTIVE AND IMPORTANCE Spinal cord injury is one of several devastating complications after operation in the sitting position. Young patients exhibiting extraordinary growth spurts demonstrate a higher risk for this complication. CLINICAL PRESENTATION We describe a 7-year-old male patient with a pineal region choriocarcinoma in whom a cervical spinal cord infarction (C5-T1) developed as an acute complication after operation in the sitting position. Preoperatively, high serum levels of human chorionic gonadotropin (5867.7 mIU/ml) and somatomedin-C (704 ng/ml) and an extreme growth velocity in height (16 cm/yr) were noted. CONCLUSION It is assumed that, in addition to head flexion, the abnormal skeletal growth spurt resulting from an excessive secretion of human chorionic gonadotropin from a tumor was a possible predisposing factor for this complication. To prevent this complication, surgeons need to pay great attention to head positioning, especially in a young patient experiencing an active growth spurt.

Duplication of the middle cerebral artery associated with an unruptured aneurysm.

A 63-year-old female with hypertension and hypercholesterolaemia was transferred to our department. Magnetic resonance angiography revealed a left internal carotid artery (IC) aneurysm. Since her younger brother exhibited a subarachnoid haemorrhage and died at the age of 39 years, she requested a further cerebrovascular examination. Angiography demonstrated an artery arising from the IC proximal to the site of its terminal bifurcation and running in a stepladder pattern. This artery seemed to supply the territory of the MCA (anterior temporal artery), the anterior and anterolateral surface of the temoral pole. This artery was identi®ed as a dupMCA. Angiography also revealed a saccular aneurysm at the origin of dupMCA (Fig. 1a). Three-dimensional computed tomography (3D-CT) demonstrated dupMCA and an aneurysm at its origin (Fig. 1b). The patient requested radical treatment for the aneurysm. During the operation, we observed that a dupMCA arose from the IC proximal to the MCA and passed into the Sylvian ®ssure along with the main MCA (Fig. 1c). An unruptured saccular aneurysm was found at the origin of the dupMCA and was clipped. A postoperative angiogram revealed complete clipping of the aneurysm (Fig. 1d). The postoperative course was uneventful. Discussion

Percutaneous transluminal angioplasty and stent placement for subclavian and brachiocephalic artery stenosis in aortitis syndrome

A 43-year-old man with progressive right common carotid, subclavian artery, and brachiocephalic artery stenoses due to aortitis syndrome is presented. The patient’s right common carotid artery had been treated by percutaneous transluminal angioplasty (PTA) four times previously, but it was finally occluded. The right subclavian artery was treated by PTA once, which resulted in restenosis. The stenosis extended to the brachiocephalic artery. For this patient, PTA followed by stent placement was performed for the right subclavian and brachiocephalic artery stenosis. Because arterial stenosis is progressive in cases of aortitis syndrome, simple PTA alone does not appear to be sufficient for treatment. We suggest that PTA followed by stent placement may be an alternative treatment for recurrent stenosis in aortitis syndrome.

Arterial spin-labeling magnetic resonance imaging for diagnosis of early seizure after stroke

BACKGROUND AND PURPOSE Arterial spin labeling (ASL) is a non-invasive modality of magnetic resonance imaging (MRI) used to evaluate cerebral perfusion without a contrast agent. The usefulness of ASL for diagnosis in the acute phase of late seizure after stroke was evaluated. METHODS Twelve consecutive patients diagnosed with late seizure after stroke were enrolled in this study. MRI including ASL was performed for each patient at the time of the emergency department visit. Eight of the patients underwent electroencephalography (EEG). RESULTS All patients showed hyperperfusion around the stroke lesion on ASL. Only 6 patients showed high signal intensity along the cerebral cortex around the stroke lesion on diffusion-weighted imaging. The patients who underwent EEG showed slow activity, but paroxysmal discharges such as spikes or sharp waves were not observed. CONCLUSIONS ASL was able to reveal hyperperfusion and was of great diagnostic value in the peri-ictal phase of late seizure after stroke.

Ocular dominance affects magnitude of dipole moment: an Meg study

To investigate whether the ocular dominance affects laterality in the activity of the primary visual cortex, we examined the relationship between the ocular dominance and latency or dipole moment measured by checkerboard-pattern and magnetoencephalography in 11 right-handed healthy male participants. Participants with left-eye dominance showed a dipole moment of 21.5±6.1 nAm with left-eye stimulation and 16.1±3.6 nAm with right, whereas those with right-eye dominance showed a dipole moment of 18.0±5.2 and 21.5±2.7 nAm with left-eye and right-eye stimulation of the infero-medial quadrant visual field, respectively. Thus, the dipole moment was higher when the dominant eye was stimulated, which implies that ocular dominance is regulated by the ipsilateral occipital lobe.