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Biomedical subjects

O Nakai

Publications and source records attributed to O Nakai.

At least 19 recordsLinked to original sources
PubMed1995

Three-dimensional-MRI of neurovascular compression in patients with hemifacial spasm.

We prospectively studied 30 patients to assess the usefulness of three-dimensional (3D) contrast-enhanced MRI in patients with hemifacial spasm. In all patients neurovascular compression of the facial nerve could be detected. Microvascular decompression was performed in 14, and vascular compression of the root exit zone of the facial nerve and the offending artery were exactly as predicted by MRI in all but 2. We also retrospectively studied whether the symptomatic side could be defined only by enhanced 3D MRI in 55 randomised individuals (30 with and 25 without hemifacial spasm). All symptomatic sides were correctly identified, and the false-positive rate was 13.8%.

Adult↗
PubMed1995

[Primary malignant T-cell-rich B-cell lymphoma of the central nervous system: a case report].

An autopsy case of primary intracranial T-cell-rich B-cell lymphoma in a 69-year-old female is presented. The patient was admitted with a diagnosis of a brain tumor in July 1993 and a month long history of mental deterioration, motor weakness of the right arm and leg, and a tendency toward somnolence. Neurological examination revealed disturbance of consciousness, right hemiparesis, and papilloedema. However, her general physical examination was unremarkable. A CT scan and MR imaging revealed an irregular enhanced mass lesion at the paraventricular deep white matter in the bilateral parieto-occipital lobe. The patient was treated with surgical biopsy of the tumor followed by combined radiotherapy (a total of 50 Gy) and chemotherapy. Following repetitive episodes of remission and exacerbation, the patient expired about seven months after the onset of symptoms. Histopathological diagnosis of the tumor was malignant lymphoma (diffuse medium-sized cell type). In the immunohistochemical study, most of the lymphoma cells had T-cell markers, such as UCHL1. Some of the lymphoma cells were L26-positive. Neither glial fibrillary acidic protein nor neuron specific enolase were reactive with the lymphoma cells. At post-mortem examination, the specimens disclosed diffuse infiltration of medium-sized lymphoma cells. By contrast, most of the lymphoma cells were shown to be positive by the analysis of L26. None of the lymphoma cells exhibited the presence of UCHL1. These immunohistochemical evaluations conform to the criteria of T-cell-rich B-cell lymphoma.

Aged↗
PubMed1992

Intracranial germinoma and Down's syndrome--case report.

A germinoma in the basal ganglia developed in a 9-year-old boy with Down's syndrome, presenting as left hemiparesis. An initial computed tomographic (CT) scan demonstrated no notable abnormalities, but serial CT scans followed the entire course of tumor growth. Subtotal removal and irradiation achieved tumor remission. This is the first case reported of intracranial germinoma associated with Down's syndrome.

Brain Neoplasms↗
PubMed1992

[Correlation between clinical symptoms and draining pathways in dural arteriovenous malformation of the cavernous region].

The clinical picture of dural arteriovenous malformations cannot be explained on the basis of degree of arteriovenous shunting in many cases. In this study, therefore we focused on the relation between clinical symptoms and draining pathways. Eighteen patients with dural arteriovenous malformation in cavernous region were studied before treatment. All patients underwent examination for their clinical symptoms, opthalmological examination and angiography on admission. Angiograms were used to determine the degree of arteriovenous shunting and the direction of draining pathway. The relationship between severity and shunt volume was inexplicable in many cases. However, close correlations appeared to exist between ocular hypertension and drainage pathways toward the orbit, between cranial nerve signs and drainage pathways toward the posterior fossa, and between headache and drainage pathways toward the cortical veins.

Adult↗
PubMed1992

[Correlation between sequential changes in angiographical findings and clinical deteriorations during management for dural AVM of the cavernous region].

The authors treated five patients with dural arteriovenous malformation of the cavernous region (DAVM) by cervical compression procedure as the initial treatment. In four of five patients clinical symptoms were aggravated during that period. The period between the beginning of cervical compression and the deterioration of clinical symptoms ranged from 11 to 20 days. In three of four patients, the angiography examined at the time of deteriorations confirmed the same amount of A-V shunt flow and otherwise the remarkable decrease of the draining pathway compared to the findings of the angiogram performed before the management. The angiography examined at the time of the remission of the symptoms showed the increase of the draining pathway in two patients and the resolution of the DAVM in another. These findings indicate that clinical courses of the DAVM and the amount of the draining pathway correlate to each other and that cervical compression procedure may occlude the important draining pathway of the DAVM.

Adult↗
PubMed1992

[Correlation between the analgesic effect by thalamic relay nucleus stimulation and somatosensory evoked potentials recorded from thalamus].

Electric stimulation of the thalamic sensory relay nucleus (Vc) has an analgesic effect on deafferentation pain, however, the analgesic effect differs from patient to patient. Electrode position and state of the substrate stimulated are considered important factors influencing the analgesic effect. In order to determine the best position for the stimulating electrodes, we recorded somatosensory evoked potentials (SEPs) from stimulating electrodes implanted in the Vc and compared thalamic SEPs with the analgesic effect of Vc stimulation. The subjects were thirteen patients with deafferentation pain, four patients with thalamic lesions, seven patients with suprathalamic lesions and two patients with infrathalamic lesions. We inserted the electrode array into the Vc stereotactically, and fixed it so that stimulation-induced paresthesia would cover the painful frea. The electrode array consisted of the four contact points of four electrodes spaced at 2 mm intervals within 10 mm from the tip. Using bipolar combinations of the four electrodes (twelve combinations in all), we stimulated the Vc for about half an hour with each combination. We then rated the degree (%) of analgesia as 100% when pain disappeared and 0% when there was no change. Thalamic SEPs elicited after stimulation of the contralateral median nerve were recorded from all four contact points simultaneously. The latencies, amplitudes and recorded positions of large early positive components (P1) followed by large negative components (N1) with latencies between 10 and 20 msec were then analyzed and compared with the best electrode combination for optimal pain relief and with the degree of analgesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Long-term roentgenographic and functional changes in patients who were treated with wide fenestration for central lumbar stenosis.

Thirty-four patients who had central stenosis of the lumbar spine were treated with wide fenestration, a procedure in which only the medial parts of the inferior facets and the adjoining ligamentum flavum were removed. The patients were followed for an average of five and one-half years (range, four and one-half years to seven years and ten months). Wide fenestration successfully relieved the symptoms. The new bone that was laid down in the operatively treated segments did not reproduce the symptoms of spinal stenosis; instead, it appeared to stabilize those segments.

Activities of Daily Living↗
PubMed1990

[Neurophysiological study on hemifacial spasm--the abnormality and origin of the electromyographic response to stimulation of the facial nerve].

Electromyographic responses (MD-OC) of the orbicularis oculi muscle to stimulation of ipsilateral marginal mandibular branch of the facial nerve were recorded in 20 patients with hemifacial spasm, pre-, post-operatively and during operations to relieve it by microvascular decompression, and the abnormal features and origin of the MD-OC were investigated. On the affected side, the MD-OC were recorded in pre- and during operative state, and disappeared with disappearance of hemifacial spasm after microvascular decompression, while no response was recorded in pre-, during and post-operative state on the healthy side. In 17 patients, the MD-OC was recorded continuously during operation. In all cases except for one case in whom the MD-OC was recorded even the end of operation, the MD-OC disappeared on several stage of procedure from dural opening through vascular mobilization. The compound nerve action potential (MD-VII) to stimulation of the marginal mandibular branch was recorded from the facial nerve near its root entry zone after exposure of the intracranial portion. There were two patterns in the records, i.e., one group consisting of early component and the other consisting of early and late component. The MD-VII was only consisted of the early component in 12 cases in whom the MD-OC have already disappeared, and was consisted of the early and late component in 5 cases in whom the MD-OC still recorded. And in 2 cases of the later, the late component disappeared simultaneously with disappearance of the MD-OC during vascular mobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Bromocriptine-induced morphological changes in cultured growth hormone-producing pituitary adenoma cells.

Tumor tissues obtained from two patients with growth hormone-producing pituitary adenomas were cultured and treated with bromocriptine, then examined for morphological changes. Untreated tumor cells (controls) were morphologically well preserved and in terms of growth hormone secretion. Tumor cells exposed to bromocriptine for 7 days contained many vacuoles, which, after 14 days of exposure, grew larger and more numerous. These vacuoles appeared to be extensions of endoplasmic reticulum: some were connected to rough or smooth endoplasmic reticulum or, occasionally, to Golgi apparatus, and there were ribosomes on their surfaces. Bromocriptine apparently has cytocidal effects on growth hormone-producing pituitary adenoma in vitro.

Adenoma↗
PubMed1989

[Intra-arterial chemotherapy of malignant glioma after osmotic blood-brain barrier disruption].

Reversible transient osmotic blood-brain barrier disruption was used to increase drug delivery to the brain. The authors treated 10 cases of malignant gliomas with intra-arterial chemotherapy after osmotic blood-brain barrier disruption. Ten patients received intra-arterial anticancer drugs (5-FU, ACNU, IFN-beta) after intra-arterial infusion of 20% mannitol to open the blood-brain barrier at the tumor site. Clinical responses in 9 evaluable cases were 1 Complete Response, 3 Partial Responses, 5 No Change and no Progressive Disease in CT examination. Response rate was 44.4% (4/9). The most untoward effect of this method was myelosuppression. Platelet and leukocyte count diminished below 20,000 and 2,000, respectively in 3 cases, and 2 out of these 3 cases died of severe infection. The other complications were eye pain during mannitol infusion in all cases, when the selective catheterization of the internal carotid artery failed to pass the origin of the ophthalmic artery. Decreased activity was seen in 70%, nausea and vomiting in 50%, swelling of external decompression area in 33%, increased neurological deficit in 20%, but all these side effects were transient. This method was considered an effective treatment for malignant gliomas.

Aged↗
PubMed1989

[Electrophysiological study on hemifacial spasm--usefulness in the etiological diagnosis and pathophysiological mechanism].

Electrophysiological studies were performed in 30 patients with idiopathic hemifacial spasm (idiopathic HFS), who underwent microvascular decompression with abolishment of spasm, and 10 patients with symptomatic hemifacial spasm (symptomatic HFS) secondary to Bell's palsy. (1) The maximum firing rate of abnormal discharges recorded from the orbicularis oris muscle during spasm in patients with idiopathic and with symptomatic HFS, and that of discharges recorded on the intact side during voluntary contraction in idiopathic HFS patients measured 181 +/- 71 Hz, 68.4 +/- 36.9 Hz, 56.3 +/- 21.8 Hz, respectively. Thus, the maximum firing rate of the discharges during spasm in idiopathic HFS patients was exceedingly higher than that in symptomatic HFS patients. (2) Electroneurography, performed to evaluate quantitatively degeneration of the facial nerve, revealed that the ENoG value (90.2 +/- 16.5%) in idiopathic HFS patients were higher than that (57.6 +/- 26.8%) in symptomatic HFS patients. (3) In blink reflex examined, synkinetic potentials (S1, S2), synchronous to the potentials consisting of the early (R 1) and late component (R 2) in the orbicularis oculi muscle, were recorded from the orbicularis oris muscle on the affected side in all patients with idiopathic and with symptomatic HFS. In sequential recording of blink reflex potentials (R 1, R 2) and synkinetic potentials (S 1, S 2), the recording pattern of synkinetic potentials was divided into variable and constant type. In the variable type, synkinetic potentials appeared unsteadily and the difference in latency between R 1 and S 1 was varied. In the constant type, synkinetic potentials appeared steadily and the difference in latency between the two was not varied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[A case of multiple cerebral hemorrhage related to cerebral amyloid angiopathy].

A case of multiple cerebral hemorrhage in the bilateral parietal lobes related to cerebral amyloid angiopathy (CAA) is reported. A 66-year-old man was admitted to our hospital because of headache and vomiting on Feb. 21, 1983. He had no history of hypertension, diabetes mellitus, recent head injury, or dementia. Four days prior to admission, he had behaved as if he were blind, but, had denied any blindness. On examination, he was confused and disoriented. Blood pressure was 130/80 mmHg. Abnormal findings on neurological examination included memory disturbance, apraxia for dressing, right-left disorientation, finger agnosia and Balint's syndrome. A CT scan showed multiple subcortical hematomas in the bilateral parietal lobes. Intracerebral hemorrhage related to CAA was suspected. Confirmation of the presence of amyloid in the cerebral vessels was established by examination of brain biopsy specimens. The characteristics of cerebral hemorrhage related to CAA are as follow--occurrence in elderly, sometimes demented people; localization to the cortex and subcortical white matter, with direct extension into the subarachnoid space; frequent multiple occurrence in time and/or at several sites within the cerebral hemispheres; sometimes occurrence after operative procedures or head injuries. A specific diagnosis of CAA can only be made by histological examination, but the indication of brain biopsy should be carefully decided because of hemostatic difficulty and tendency to rebleed. In conclusion, CAA should be considered as a cause of hemorrhage in elderly patients who are often normotensive and demented.

Aged↗
PubMed1986

[Responsiveness of brain tumors to chemotherapeutic agents in the subrenal capsule assay].

The 6-day subrenal capsule assay was used to determine chemotherapeutic sensitivities of brain tumors. Twenty-nine brain tumors were obtained at the time of surgical resection. A minced tumor fragment (1-mm cube) was implanted under the renal capsule of 5- to 8- week-old normal female ddY mice. Each fragment was measured at two diameters using ocular micrometer unit (10 omu = 1.0 mm). The animals were randomized, usually 5 to 7 per group, and treated with anticancer drugs on day 1 through 5. On day 6, the mice were killed. The kidney was exteriorized and the tumor was again measured. The change in tumor size was obtained for each animal by ratio of the final tumor size/the initial tumor size. Sensitivities of tumors to anticancer agents were determined by comparing differences in mean values of the change in tumor size between control and treated group. Twenty-seven out of 29 specimens (93%) were submitted to evaluable assay. The response rate of 11 malignant gliomas (grade 3 and 4) was 44% and that to anticancer drugs tested were as follow: 5-FU 78%, ACNU and CPA 50%, VCR 40%, CDDP 36%. The response rate of 3 medulloblastomas was 36%: MTX 67%, CPA 50%, ACNU and CDDP 33%. That of two low-grade gliomas (grade 2) was 29%, while that of 4 malignant brain tumors (2 metastasis, chordoma, malignant fibrous histiocytoma) was 60%. Four neurinomas and 3 meningiomas were not sensitive to Tamoxifen and none were determined for estrogen receptor. In histological analysis, the transplanted tumor retained similar characteristics to the original tumor in the cases of neurinomas, meningiomas and some gliomas. Lymphocytic infiltration was observed in many cases. In the cases of metastasis (adenocarcinomas), considerable mesenchymation and lymphocytic infiltration was observed, tumor cells were reduced in number with poor preservation. Clinical response in 9 cases treated with sensitive drugs were 1 complete response, 2 partial response, 5 stable and 1 progressive disease in CT examination. The subrenal capsule assay is therefore considered to be very useful for determining suitable chemotherapeutic agents for brain tumors.

Animals↗
PubMed1982

Dynamics of contrast enhancement in delayed computed tomography of brain tumors: tissue-blood ratio and differential diagnosis.

Thirty-one patients with brain tumors were studied by delayed computed tomographic (CT) scanning performed one and two hours after intravenous administration of contrast medium. Dynamics of contrast enhancement in the lesion were analyzed quantitatively and qualitatively by calculating the tissue-blood ratio (TBR) at each scan, and are expressed as relative TBR (R-TBR). The R-TBRs obtained two hours after the first contrast-enhanced scan were found to be most useful in diagnosis, and were classified into three groups: less than 1.5 (Class I), 1.5 to 3.0 (Class II), and more than 3.0 (Class III). In the glioma group, seven of eight anaplastic gliomas were Class III and all of three anaplastic astrocytomas were Class II. All of seven meningiomas were Class I. Four of five pituitary adenomas were Class II. Three of four neurinomas were Class III. This method is potentially useful in differential diagnosis of some brain tumors.

Adenoma↗