Recombination processes and photoluminescence intensity in quantum wells under steady-state and transient conditions.
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Journal Article↗
Biomedical subjects
T Isu
Publications and source records attributed to T Isu.
Immunohistochemical analysis of giant cell glioblastoma.
Giant cell glioblastoma (GCG) is one of a group of rare tumors in which the cell population is abnormally large and includes multinucleated cells of gigantic sizes. Immunohistochemical studies were performed on four GCG cases and found that all giant cells and/or tumor cells were positive for glial fibrillary acidic protein (GFAP), S-100 protein, and vimentin, thus verifying the tumor's glial origin. The nuclei of multinucleated giant cells of three adult cases were frequently immunostained for proteins expressed during the cell cycle (proliferating cell nuclear antigen (PCNA) and Ki-67), thereby demonstrating the proliferative capacity of these cells. By contrast, those of a 12 year old girl expressed these cell cycle markers rather infrequently. Alpha I-antitrypsin was detected with relatively high frequency in the giant cells, and its presence may explain their bizarre sizes and pericellular reticulin fiber formation. A literature review of 32 cases revealed that the GCG that occurs preferentially in young girls is a type of pleomorphic xanthoastrocytoma. By contrast, GCG in adult males has the same age incidence as ordinary glioblastomas and, as these, expresses high levels of cell cycle-related proteins. Thus, GCG, which is subclassified morphologically as ordinary glioblastoma, has distinct biological and clinical characteristics, with that in children requiring re-evaluation because of its similarities to pleomorphic xanthoastrocytoma.
Age Factors↗
[A case of a young infant with Chiari II malformation treated by only bony foramen magnum decompression].
A case of a young infant with Chiari II malformation treated by only foramen magnum decompression was reported. The patient was a 3-month-old infant with a one-month history of stridor and respiratory distress. The myelomeningocele was surgically repaired. At the age of two weeks, a ventriculoperitoneal shunt had been inserted. On admission, MRI demonstrated Chiari II malformation. The shunt mechanism was functioning. Suboccipital craniectomy and upper cervical laminectomy from C1 to C5 level was performed. After the removal of the dural band at the foramen magnum level, good pulsation of the dura mater was demonstrated. After surgery, the stridor and respiratory distress disappeared. Foramen magnum decompression carried out by our surgical technique is advantageous because all the procedures are extradural and there are, therefore, fewer postoperative complications than the foramen magnum decompression techniques previously reported.
Arnold-Chiari Malformation↗
Remote epileptogenic focus detected by electrocorticogram in a case of cavernous angioma.
In a case of cavernous angioma, a remote gyrus, which was found to contain an epileptogenic focus by intraoperative electrocorticography (ECoG), was resected simultaneously with lesionectomy. The patient was a 27-year-old male who was referred to our hospital because of frequent systemic tonic-clonic convulsions. ECoG revealed an epileptogenic focus not only in the cortex around the angioma-affected tissue of the left frontal lobe but also in an angioma-free remote gyrus. These epileptogenic foci were removed in addition to lesionectomy. The postoperative course was uneventful. Now (two years after surgery), the patient is seizure-free without any anti-convulsive agent. In the surgical treatment of convulsions-accompanied by cavernous angioma, it is essential not only to detect epileptogenic foci by intraoperative ECoG but also to remove these foci together with the angioma.
Adult↗
Evaluation of the patency of an extracranial-intracranial bypass using magnetic resonance angiography with selective presaturation of bypass vessels.
Three-dimensional time-of-flight magnetic resonance (MR) angiography using radiofrequency presaturation pulses was used to evaluate the patency of extracranial-intracranial (EC/IC) bypass in 11 patients. Presaturation causes signal loss in the vascular territory supplied by the presaturated EC/IC bypass graft. In all patients with a patent EC/IC bypass graft confirmed on conventional angiography, disappearance of the signal of the middle cerebral artery receiving blood flow from the bypass graft was clearly observed on MR angiograms with presaturation, indicating patency of the EC/IC bypass graft. MR angiography with presaturation pulses is a noninvasive and repeatable method for evaluation of the function of an EC/IC bypass graft.
Adult↗
The surgical technique of anterior cervical fusion using bone grafts obtained from cervical vertebral bodies.
The authors describe the surgical technique of anterior cervical fusion using bone grafts obtained from cervical vertebral bodies. This series consisted of 90 patients with cervical intervertebral disc disease suffering from cervical spondylotic myelopathy. Thirty-five patients were operated on at one level, 33 at two levels, and 22 at three levels. Postoperative x-ray films showed solid bone fusion in all patients at a mean follow-up time of 24 months (range 1 year to 3 years 6 months). Anterior angulation was found in four (4.4%) of the 90 patients. This surgical procedure has two major advantages: 1) there are no complications related to the iliac donor site, allowing early patient mobilization; and 2) the extensive posterior spur can be removed safely and easily under a wide operative field without damaging the spinal cord and nerve roots.
Adult↗
[Surgical treatment for ossification of the posterior longitudinal ligament of the cervical spine].
The surgical results in 37 patients with cervical myelopathy due to ossification of the posterior longitudinal ligament of the cervical spine were described. This series consisted of 32 patients who underwent anterior decompression with anterior cervical fusion using bone grafts obtained from cervical vertebral bodies, and 5 patients who underwent expansive laminoplasty or laminectomy as a method of posterior decompression. 6 out of 32 patients with anterior cervical fusion were operated on at one level, 18 at two levels and 8 at three levels. The patients were out of bed within two days and treated using a soft collar for 3 months. In all patients, the symptoms improved postoperatively. Postoperative X-ray films showed solid bone fusion in all patients with anterior cervical fusion at a mean follow up time of one year and nine months (range 6 months to 3 years 6 months). Anterior angulation was found in one (3%) out of 32 patients who underwent anterior cervical fusion. Concerning the method of operation, the authors think that anterior decompression is to be recommended for cases with ossification within three consecutive vertebrae and posterior decompression should be applied to cases in which anterior decompression is very difficult. If necessary, a two-stage combined decompression is recommended.
Adult↗
Spontaneous drainage in syringomyelia.
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Arnold-Chiari Malformation↗
[Evaluation of EC-IC bypass flow by MR angiography using the presaturation technique].
MR angiography studies using the presaturation technique were performed in 7 patients who had received extra-intracranial (EC-IC) bypass surgery. With presaturation on the bypass vessels, disappearance of intracranial vascular signals suggests bypass effect. In our studies, good bypass effect was shown in 3 cases and poor effect in 2 cases, which correlates well to concurrent angiography. In two cases, bypass effect was shown only in a few cortical branches of MCA, but angiography confirmed recanalization of occluded internal carotid artery in one case, and growth of large network of transdural anastomoses in the other.
Adult↗
Spinal cord evoked potential monitoring after spinal cord stimulation during surgery of spinal cord tumors.
Spinal cord evoked potentials (SCEPs) after spinal cord stimulation were used as a method of spinal cord monitoring during surgery of 6 extramedullary and 14 intramedullary spinal cord tumors. SCEPs were recorded from an epidural electrode placed rostral to the level of the tumor. Electrical stimulation was applied on the dorsal spinal cord from a caudally placed epidural electrode. The wave forms of SCEPs consisted of a sharp negative peak (N1) in 15 cases and two negative peaks (N1 and N2) in 5 cases. The N2 wave was markedly attenuated by posterior midline myelotomy, whereas the N1 activity showed less-remarkable changes by myelotomy. An increase in N1 amplitude was observed after the removal of the tumor in four extramedullary and three intramedullary cases. Of six patients that showed decreased N1 amplitude after the removal of the tumor, five patients developed postoperative motor deficits. However, there were four false-negative cases and one false-positive case in regard to changes of N1 amplitude and postoperative motor deficits. Four false results occurred in intramedullary cases. In two of them, postoperative symptoms indicated intraoperative unilateral damage to the spinal cord. The position of the stimulating electrode, the difference in thresholds of the axons for electrical stimulation between the right and left side of the spinal cord, or the change of the distance between the electrode and the spinal cord surface may account for these false results. Thus, our analysis of the changes of SCEP wave forms and early postoperative symptoms indicates that the sensitivity of this monitoring method to detect intraoperative insults to the spinal cord is unsatisfactory in spite of the reproducible wave forms. We conclude that SCEP monitoring can be used as an alternative method or in combination with other types of evoked potentials in patients with severe spinal cord lesions who show abnormal somatosensory evoked potentials preoperatively.
Adult↗
[Linac-knives].
Stereotactic radiotherapy using linear accelerators (Linac-knives) is a promising approach for treatment of metastatic brain tumors, arterio-venous malformations, and benign brain tumors. The advantages of the linac-knife over the Gamma knife are its capacity for stereotactic fractionated radiotherapy and to extend the indication for head and neck tumors and cervical spinal tumors.
Arteriovenous Malformations↗
[Prospective dose-escalation study in stereotactic radiotherapy utilizing a linear accelerator: report from East Hokkaido Radiosurgery Study Group (EHRSSG)].
Stereotactic radiotherapy utilizing a linear accelerator has been investigated. (1) Radiosurgery, (2) fractionated stereotactic radiotherapy, and (3) fractionated radiotherapy followed by stereotactic boost have been performed according to pathology, size, and prognosis of diseases. Accuracy in localization of the treatment center was within one millimeter using a CT simulator. From July, 1990 to December 1992, 69 lesions in 63 patients have been treated using the stereotactic radiotherapy according to prospective dose-escalation design. Five patients have experienced transient worsening of nerve palsy or headache, but these complications were self-limited. No late radiation damage was observed over a mean follow-up period of 12.5 months. Encouraging improvements were obtained in patients with metastasis, AVM, and acoustic neurinoma although the follow-up period was too short to be conclusive. Stereotactic radiotherapy utilizing a linear accelerator is thus suggested as a safe and effective approach providing that dose-volume-time relationship is well controlled.
Adolescent↗
Foramen magnum decompression with removal of the outer layer of the dura as treatment for syringomyelia occurring with Chiari I malformation.
The surgical results of foramen magnum decompression in seven patients with syringomyelia associated with Chiari I malformations are reported. The patients were two men and five women, ranging in age from 23 to 54 years (mean, 30 yr). A bony foramen magnum decompression combined with the removal of the outer layer of the dura mater was performed in seven patients. In an average postoperative follow-up period of 2 years (range, 1-3 yr), neurological symptoms and signs improved in six of seven patients and were unchanged in one patient. Postoperative magnetic resonance imaging scans taken a few weeks after surgery showed a decrease in the size of the syrinx or a disappearance of the syrinx in five of seven patients; a few months were required for a similar reduction in the remaining two patients. In all seven patients, the decompression of the foramen magnum proved to be sufficient, as disclosed by postoperative magnetic resonance imaging. Foramen magnum decompression by our surgical technique is advantageous because all the procedures are extradural and there are, therefore, fewer postoperative complications than the foramen magnum decompression techniques previously reported. Foramen magnum decompression by the authors' surgical technique is effective as the initial surgical treatment for syringomyelia associated with Chiari I malformations.
Adult↗
[Intraoperative monitoring for spinal cord tumor by spinal cord evoked potential following unilateral spinal cord stimulation].
We described our experiences with intraoperative spinal cord monitoring in 6 cases of spinal cord tumor. During the operation, spinal cord evoked potential following unilateral spinal cord stimulation was recorded from subdural monitoring electrodes. This series included two cases of intradural extramedullary tumor (one case each of neurinoma and of meningioma) and four cases of intramedullary tumor (2 cases of cavernous angioma, one case each of ependymoma, and of glioblastoma multiforme). Before the removal of the tumor, the spinal cord evoked potential showed lower amplitude or no response on the more affected side in all 6 cases. During the operation, the different intraoperative changes were shown on each side. The authors think that the detection of unilateral damage to the spinal cord is possible in spinal cord evoked potential using unilateral spinal cord stimulation.
Adult↗
[Syringomyelia secondary to adhesive arachnoiditis: clinical profiles and efficacy of shunt operations].
The authors report nine cases of syringomyelia secondary to adhesive arachnoiditis treated in our institute from 1982 to 1991. Neurological signs, radiological features, and results of surgical treatment were reviewed. Common initial manifestations in association with syringomyelia were spastic paraparesis in 8 patients (88.9%), regional sensory loss in 4 (44.4%), neurogenic bladder in 4 (44.4%), and somatic pain in 2 (22.2%). All the neurological symptoms or signs progressed gradually for years. All the patients were treated with various modes of shunt operations, including syringo-peritoneal shunt in seven patients, syringo-subarachnoid shunt in one, and ventriculo-peritoneal shunt in one, respectively. Three patients who failed to resolve their major complaints after the first surgery further received syringo-peritoneal shunts. Postsurgical follow-up periods ranged from 18 months to 10 years. Serial MR imaging revealed a significant reduction of the size of syringomyelia in 8 of 9 patients. However only 6 patients showed certain improvement of neurological deficits. Three patients who failed to improve clearly had a long (beyond 15 years) history of syringomyelia before the first surgical treatment. A total of 11 syringo-peritoneal shunts were done in 8 patients of whom 5 patients improved neurologically. It was noticed that 4 of 5 successful syringo-peritoneal shunts were placed in the caudal level of the syrinx. In conclusion, syringo-peritoneal shunt may be at present an optimal mode of surgical management for syringomyelia secondary to adhesive arachnoiditis. In addition, we would like to recommend that follow-up serial MR imaging be done for patients having adhesive arachnoiditis in order to detect syringomyelia as early as possible.
Arachnoiditis↗
Scoliosis associated with syringomyelia presenting in children.
The clinical presentations and radiological features of scoliosis accompanying syringomyelia were analyzed in 14 cases of syringomyelia associated with a in 14 cases of syringomyelia associated with a Chiari malformation in children. Scoliosis was the initial symptom in 11 out of 16 patients (64%) with syringomyelia and present in 14 (88%) at the initial examination. The scoliosis associated with syringomyelia was characterized by a higher incidence of a single curve (6 cases, 43%) and convexity to the left (7 cases, 50%) than seen in idiopathic scoliosis. The syrinx was shifted to the convex side of scoliosis on the axial section at the middle or lower thoracic level in patients with a single curve, and at the cervical or upper thoracic level in patients with a double curve. The authors think that the scoliosis develops in children as a result of damage done to the anterior horn, which innervates the muscles of the trunk, by an asymmetrically expanded syrinx.
Arnold-Chiari Malformation↗
Sacral nerve root cysts manifesting as localized unilateral perineal pain--case report.
A 62-year-old female presented with multiple sacral nerve root cysts manifesting as localized unilateral perineal pain. Myelography just after contrast material injection revealed multiple cysts at the sacral level. However, perioperative dye injection showed hardly any flow in the reverse direction. Only the S3 nerve was constricted by hyperplasia of the dura mater, and adhered to the cyst wall. Other nerves were not constricted, nor adhered to cyst walls. The S3 nerve constriction and tight adhesion was the cause of the pain. The one-way flow of spinal fluid from the spinal subarachnoid space to the cysts is probably closely correlated with cyst formation.
Cysts↗
[New surgical technique for anterior cervical fusion; surgical technique for anterior cervical fusion utilizing autogenous bone graft from the cervical vertebrae].
Since April, 1990, the authors have been reporting a surgical technique for anterior cervical fusion utilizing autogenous bone graft from the cervical vertebrae. This series included 53 patients (40 males and 13 females). The age ranged from 24 to 72 years with a mean of 49 years. There were 42 cases of cervical disc disease, and 11 cases of cervical disc disease with ossification of the posterior longitudinal ligament (OPLL). The patient was out of bed within two days and treated in a soft collar for 3 months. In all patients, the symptoms improved postoperatively. Postoperative X-ray showed slight anterior angulation deformity in 3 out of 53 cases (6%). The advantages of our surgical technique are as follows: 1) There are no problems related to the iliac donor site 2) The removal of posterior spur and localized OPLL is safely and easily performed.
Adult↗