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ABSTRACT: In neutron capture therapy, the therapeutic effect of the boron compound is based on alpha particles produced by the B(n, alpha) reaction while with the gadolinium compound the main radiation effect is from gamma rays derived from the Gd(n, gamma) reaction. The uptake and distribution within the tumor may be different among these compounds. Thus, the combination of the boron and gadolinium compounds may be beneficial for enhancing the radiation dose to the tumor. Chinese hamster fibroblast V79 cells were used. For the neutron targeting compounds, 10B (BSH) at 0, 5, 10, and 15 ppm, and 157Gd (Gd-BOPTA) at 0, 800, 1600, 2400, 3200, and 4800 ppm, were combined. The neutron irradiation was performed with thermal neutrons for 30 min. (neutron flux: 0.84 x 10(8) n/cm2/s in free air). The combination of the boron and gadolinium compounds showed an additive effect when the gadolinium concentration was lower than 1600 ppm. This additive effect decreased as a function of gadolinium concentration at 2400 ppm and resulted in no additive effect at more than 3200 ppm of gadolinium. In conclusion, the combination of the boron and gadolinium compounds can enhance the therapeutic effect with an optimum concentration ratio. When the gadolinium concentration is too high, it may weaken the boron neutron capture reaction due to the high cross-section of gadolinium compound against neutrons.
Journal of experimental & clinical cancer research: CR 04/2005; 24(1):93-8. · 1.50 Impact Factor
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ABSTRACT: Brown-Sequard Syndrome (BSS) caused by cervical spondylosis (CS) is rare. About 70% of patients with CS presenting with BSS show lesion-dermatome discrepancy, which may be due to spinal cord lamination. From the clinical point of view, this discrepancy should be carefully evaluated and these patients should be treated as an emergency.
Journal of Clinical Neuroscience 12/2004; 11(8):898-900. · 1.25 Impact Factor
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ABSTRACT: There are no reports of hydrocephalus following radiosurgery for a meningioma. We report on a case where gamma knife therapy for a 4 cm diameter right cerebellopontine meningioma accelerated hydrocephalus three months post treatment. Examination of the cerebrospinal fluid (CSF) revealed a high protein level and thus, CSF malabsorption and CSF obstruction might have occurred after the radio surgery. It is important to consider this pathology, and the need for long term follow up.
Journal of Clinical Neuroscience 10/2004; 11(7):785-7. · 1.25 Impact Factor
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ABSTRACT: A 23-year-old woman presented with ipsilateral hemiparesia due to rupture of a left occipital arteriovenous malformation (AVM). Emergency decompression (the onset-operation interval was 46 minutes,) was carried out and the patient could leave the hospital upon recovery without neurological deficits. In general, Kernohan's phenomenon is caused by the gradual displacement of the cerebral peduncle against the tentorial edge caused by compression by the contralateral mass. This phenomenon is very rare among the cases with spontaneous intracranial hemorrhage and only three cases including the present one have been reported in the literature. In all cases the onset-operation intervals of were very short. Kernohan's phenomenon associated with a ruptured AVM is a rare condition and emergency decompression is required.
Journal of Clinical Neuroscience 06/2004; 11(4):444-6. · 1.25 Impact Factor
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ABSTRACT: Of 175 patients with 181 aneurysms initially treated with Guglielmi Detachable Coils (GDC), 25 were retreated. All retreatments except one were performed on previously ruptured aneurysms. Thirteen aneurysms were retreated because of recurrence, and 12 aneurysms were retreated to complete initial insufficient embolization. Sixteen patients underwent re-embolization and 9 patients were operated upon surgically. No complications related to the retreatment were experienced. We consider that repeat embolization should be attempted before considering surgical treatment in case that additional therapy is required. However, it is difficult to retreat aneurysms having wide necks. In regard to surgical clipping, aneurysms without a coil in the neck are easier to treat with primary clipping, whereas aneurysms with a coil mass in the neck are difficult to surgical clip. We have never used temporary clipping and coil extraction if the distance between the coil and the parent artery was wider than 2 mm. Emerging new embolic agents or devices and technical improvement might decrease the need for retreatment and increase long-term efficacy after endovascular treatment.
Interventional Neuroradiology 03/2004; 10 Suppl 1:167-71. · 0.56 Impact Factor
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ABSTRACT: Three patients with a persistent vegetative state after severe head injury are reported. They recovered from a prolonged disturbance of consciousness after the administration of levodopa. These patients all had parkinsonian features. On magnetic resonance imaging, the distribution of lesions implied a diffuse axonal injury involving the substantia nigra or ventral tegmental area. The existence of patients whose dopaminergic systems may have been selectively damaged by a severe head injury should be recognised because such individuals may respond to levodopa treatment.
Journal of Neurology Neurosurgery & Psychiatry 12/2003; 74(11):1571-3. · 4.76 Impact Factor
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ABSTRACT: A 72-year-old woman was admitted with rapidly progressive paraplegia and sphincter disturbance. T2-weighted images of the thoracic spine showed intramedullary high signal with flow voids suggesting dilated medullary veins. Conventional spinal angiography demonstrated a dural arteriovenous fistula draining into perimedullary veins. Perfusion-weighted MRI demonstrated a prolonged mean transit time and increased blood volume in the high-signal area. The loss of normal perfusion gradient and venous hypertension and were thought to produce these differences. The time-to-peak was almost identical in the high-signal and isointense areas, although the bolus of contrast medium arrived earlier in the former. Arteriovenous shunting was thought to cause faster inflow. These changes may have resulted in increased blood volume in the spinal cord. The high signal has been attributed to oedema due to venous congestion, but there has been no histological confirmation. Perfusion MRI in this case supports this hypothesis.
Neuroradiology 11/2003; 45(10):744-7. · 2.82 Impact Factor
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ABSTRACT: Cerebral ischaemia-reperfusion injury is associated with the generation of reactive oxygen species during the early phases of reoxygenation. EPC-K1, a phosphate diester of vitamins C and E, has been reported to possess potent hydroxyl radical scavenging activity. This study was performed to investigate the effectiveness of EPC-K1 in attenuating cerebral ischaemia-reperfusion injury in a rat model of transient focal cerebral ischaemia.
We evaluated the efficacy of EPC-K1 by measuring the concentration of cerebral thiobarbituric acid reactive substances (TBARS), an indicator of the extent of lipid peroxidation by free radicals, and infarct size in rats subjected to one hour of cerebral ischaemia and 4, 24, or 72 hours of reperfusion.
EPC-K1 significantly reduced both the cerebral TBARS level and the infarct size in a rat model of transient focal cerebral ischaemia. These results indicate that EPC-K1 administration during the early stages of reperfusion ameliorates ischaemic brain injury by inhibiting lipid peroxidation.
This report is the first to describe the protective mechanism of EPC-K1 by measuring both the TBARS level and infarct size in a rat model of transient focal cerebral ischaemia, and may suggest a potential clinical approach for the treatment of ischaemic cerebrovascular disease.
Acta Neurochirurgica 07/2003; 145(6):489-93; discussion 493. · 1.52 Impact Factor
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ABSTRACT: The role of intraoperative angiography in the surgical treatment of cerebrovascular malformations remains controversial. The authors report on their experiences with intraoperative angiography in a series of 20 cases with cerebrovascular malformation to determine whether the use of intraoperative angiography has a favorable impact on the surgical treatment of cerebrovascular malformations.
Intraoperative angiography was performed in the surgical resection of arteriovenous malformation in 18 patients and in the surgical obliteration of arteriovenous fistula in 2 patients. The incidence of unexpected findings, such as residual nidus, demonstrated by intraoperative angiography was determined.
High-quality subtraction images were obtained by intraoperative angiography in every case and the findings prompted an additional procedure in 1 case that displayed an unexpected residual nidus (5.6%). There were no complications from the intraoperative angiography procedure.
Intraoperative assessment of technical results prior to wound closure offers the neurosurgeon the opportunity to resect or obliterate a vascular malformation completely, obviating a second operation.
Acta Neurochirurgica 06/2003; 145(5):377-82; discussion 382-383. · 1.52 Impact Factor
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Radiation Research 06/2003; 159:670-675. · 2.68 Impact Factor
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ABSTRACT: We present a case of a thoracic schwannoma with an intravertebral component, a so-called "dumbbell-type" tumor, that was resected with a combined minimally invasive approach using microsurgery and thoracoscopic surgery simultaneously. A 31-year-old man was admitted to our hospital for treatment of a thoracic schwannoma 45 mm in maximal diameter at the level of the third thoracic vertebra. After the tumor was separated from intravertebral structures by using a microsurgical technique via the posterior approach with a hemilaminectomy and minimal unilateral facetectomy, the mass was removed completely by using video thoracoscopy. We stress that this approach should be the most useful and less invasive technique for treating the dumbbell-type of thoracic neurogenic tumor compared with a single or combination technique involving thoracotomy, multi-level laminectomy and costotransversectomy. Below, we make some notes on this technique from the neurosurgeon's standpoint.
min - Minimally Invasive Neurosurgery 01/2003; 45(4):251-3. · 0.70 Impact Factor
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ABSTRACT: In neutron capture therapy, it is important that the boron is selectively uptaken by tumor cells. In the present study, we used flow cytometry to sort the cells in the G0/G1 phase and those in the G2/M phase, and the boron concentration in each fraction was measured with inductively coupled plasma atomic emission spectroscopy. The results revealed that sodium borocaptate and boronophenylalanine (BPA), were associated with higher rates of boron uptake in the G2/M than in the G0/G1 phase. However, the difference was more prominent in the case of BPA. The G2/M:G0/G1 ratio decreased as a function of exposure time in BPA containing culture medium, thereby indicating the cell cycle dependency of BPA uptake. Such heterogeneity of boron uptake by tumor cells should be considered for microdosimetry.
Cancer Letters 01/2003; 187(1-2):135-41. · 4.24 Impact Factor
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ABSTRACT: The aim of this study was to determine the in-phantom thermal neutron distribution derived from neutron beams for intraoperative boron neutron capture therapy (IOBNCT). Gold activation wires arranged in a cylindrical water phantom with (void-in-phantom) or without (standard phantom) a cylinder styrene form placed inside were irradiated by using the epithermal beam (ENB) and the mixed thermal-epithermal beam (TNB-1) at the Japan Research Reactor No 4. With ENB, we observed a flattened distribution of thermal neutron flux and a significantly enhanced thermal flux delivery at a depth compared with the results of using TNB-1. The thermal neutron distribution derived from both the ENB and TNB-1 was significantly improved in the void-in-phantom, and a double high dose area was formed lateral to the void. The flattened distribution in the circumference of the void was observed with the combination of ENB and the void-in-phantom. The measurement data suggest that the ENB may provide a clinical advantage in the form of an enhanced and flattened dose delivery to the marginal tissue of a post-operative cavity in which a residual and/or microscopically infiltrating tumour often occurs. The combination of the epithermal neutron beam and IOBNCT will improve the clinical results of BNCT for brain tumours.
Physics in Medicine and Biology 08/2002; 47(14):2387-96. · 2.83 Impact Factor
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ABSTRACT: We studied chronological magnetic resonance spectral changes in brain abscesses before and after medical and/or surgical treatment. We examined five patients with MRI imaging and (1)H magnetic resonance spectroscopy (MRS) on two or more occasions, using two volume-of-interest patterns, and saw chronological changes related to the evolution of the abscess. A spectrum specific for brain abscess was found in three of the five cases, while two showed a single lactate peak in the first study. In two cases, phenylalanine or alanine appeared in the second study. We observed the disappearance of the specific spectra and a single lactate peak following surgery. Only one patient showed different spectra in different volume of interest.
Neuroradiology 08/2002; 44(7):574-8. · 2.82 Impact Factor
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ABSTRACT: Non-communicating hydrocephalus can cause rupture of the lateral or third ventricle, generally in the medial wall of the trigone or the posterior wall of the third ventricle, resulting in a cystic lesion known as ventricular diverticulum. In this paper, we describe a rare case of ventricular diverticulum located in the posterior horn of the lateral ventricle and expanding to bulge with a convexity reaching into the subdural space in a neonate. Aplasia cutis congenita and a bone defect were also present in the same neonate. Early surgical repair of the scalp defect and ventriculoperitoneal shunting were performed. In addition to illustrating the rare co-existence of a ventricular diverticulum at the posterior horn of the lateral ventricle and aplasia cutis congenita in a neonate, this case also offers new insights into the pathogenesis of these congenital anomalies.
Child s Nervous System 01/2002; 17(12):750-3. · 1.54 Impact Factor
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ABSTRACT: Between March, 1997 and June, 2000, 104 aneurysms, including 75 ruptured and 29 unruptured aneurysms, were treated with Guglielmi detachable coils by 120 embolizations in our institution. Intraprocedual perforation occurred in four cases, representing 3.3% of the embolizations. Subsequently, two cases deteriorated, and the other two cases recovered completely without any deficit. Aneurysmal perforations mostly occurred in acutely ruptured aneurysms, small aneurysms less than 4 mm, anterior communicating artery aneurysms, or first coil delivery. Rebleedings in the acute period of subarachnoid hemorrhage occurred in four cases of partial occlusion due to aneurysmal morphology, such as a wide neck or an irregular shape. Rebleedings in the chronic period occurred in two cases, one of which rebled two months after partial occlusion, and the other of which rebled 27 months after nearly total occlusion. No subarachnoid hemorrhages documented from previously unruptured aneurysms occurred after embolizations. Insufficient embolization for ruptured aneurysms cannot prevent rebleeding, and partially occluded aneurysms and recurring aneurysms in the follow-up period require immediate re-treatment.
Interventional Neuroradiology 12/2001; 7(Suppl 1):83-7. · 0.56 Impact Factor
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ABSTRACT: An 8-year-old boy presenting with a transient weakness of the left extremities had a rare association of moyamoya disease and persistent primitive hypoglossal artery (PPHA). Digital subtraction angiography demonstrated intracranial moyamoya vessels and a PPHA on the right side. There was collateral blood flow from the posterior circulation to the anterior circulation, with the PPHA functioning as a blood supplier vessel. The patient underwent multiple burr hole formation, and neovascularization via the burr holes was observed on follow-up angiography. In this case, blood flow into the posterior circulation via the PPHA, which served as the collateral vessel to the moyamoya phenomenon, may have disturbed the spontaneous closure of the PPHA. Thus, this case serves as a basis for studying important pathogenic and embryological processes that contribute to the development of these vascular abnormalities.
Pediatric Neurosurgery 12/2001; 35(5):262-5. · 0.70 Impact Factor
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ABSTRACT: We report two cases of atretic cephalocele, a diverse form of cranium bifidum. The patients were 15-year-old and 3-month-old girls, who each had a hard, nonpulsatile, nonreducible lump covered by alopecic scalp in the parieto-occipital area. They were surgically treated. In case 2, microscopical examination of the operative specimen revealed a meninges under the mass, which was devoid of nervous tissue. Such lesions have rarely been reported, and their essential nature is still the subject of controversy. Pathological and embryological aspects of atretic cephalocele are discussed on the basis of the findings; the neural crest remnant was assumed to be the developmental origin of the lesion in each of these cases.
Child s Nervous System 12/2001; 17(11):674-8. · 1.54 Impact Factor
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ABSTRACT: The authors present a case of a rare cutaneous lesion resembling a human finger that protruded from the posterior thoracic region of a 7-month-old girl who was examined after the fingerlike protrusion was noted at birth. The protrusion measured 3 cm in length and 1 cm in diameter. It was located at the level of T-12 and was surrounded by angiomatous and lipomatous tissue. A computerized tomography scan demonstrated three bones in the protrusion. including deformities of the T-9 and T-10 and T-11 dysraphism. Magnetic resonance imaging revealed a hyperintense signal on the T1-weighted sequence and a hypointense signal on the T2-weighted sequence, which was visualized at the attachment to the spinal cord from T9-11. After removal of the fingerlike structure and subcutaneous mass, a T10-11 laminectomy and removal of the intradural mass were performed. Histological examination showed that the appendage was composed of nail, three bones, cartilage, and normal skin. This appendage can be recognized not only as a variant type of caudal appendage but as an ectopic finger and fingernail. The authors discuss the developmental differences among the protrusion in the present case and ordinary caudal appendages.
Journal of Neurosurgery 11/2001; 95(2 Suppl):250-2. · 2.96 Impact Factor
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ABSTRACT: Widely accepted pathologic classification of venous malformations includes discrete venous, arteriovenous, capillary, and cavernous malformations, each with distinct pathological criteria for definition. Several authors have described mixed or transitional vascular malformations with pathological features of more than one type of malformation within the same lesion. We present a rare case of a venous malformation associated with an arteriovenous malformation (AVM).
A 37-year-old woman presented with a loss of consciousness. Computed tomography showed an enlarged vein running along the lateral wall of the right lateral ventricle. A cerebral angiogram demonstrated an AVM and a venous malformation in the right hemisphere; the AVM and the venous malformation were located in proximity to each other with the AVM using the venous malformation as its draining vein. In this case, where an AVM used the venous malformation as the draining vein, only the AVM was treated by proton-beam radiosurgery. Follow-up magnetic resonance angiography demonstrated complete obliteration of the AVM with the venous malformation remaining unchanged.
Arteriovenous shunting would have disturbed venous drainage resulting in the development of the venous malformation. Thus, in addition to demonstrating a rare coexistence of AVM and venous malformation, this case also offers a new insight into the pathogenesis of these vascular malformations.
Surgical Neurology 10/2001; 56(3):170-4. · 1.67 Impact Factor
