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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↗
PubMed1994

Long-term results of microvascular decompression for trigeminal neuralgia with reference to probability of recurrence.

Sixty-one patients with trigeminal neuralgia who underwent microvascular decompression were analysed. Vascular compression of the trigeminal nerve root was found in all cases. The recurrence rate of pain in this series was 18% with an average follow-up of 80 months (range: 13 to 126 months). Ten patients developed recurrence of their trigeminal neuralgia during follow-up. Fifteen factors, including the clinical and operative findings in the pain-free patients versus the 10 patients with recurrence were analysed. Only the patients with venous compression singly or in combination with arteries were significantly related to recurrence. There was no relationship between recurrence and the duration of symptoms or the degree of compression. Based on vascular compression as the sole cause of TN, the results and interesting findings can not be explained. With reference to the hypothesis that vascular compression is only one of at least two causative factors for the development of trigeminal neuralgia, it is suggested that the intrinsic lesion in trigeminal neuralgia may be responsible for late recurrence.

Adult↗
PubMed1994

Hearing preservation and improvement of auditory brainstem response findings after acoustic neuroma surgery.

Among 9 patients with acoustic neuroma who underwent tumor removal by the middle cranial fossa approach during the past 5 years, 6 were selected for hearing preservation surgery which was successful in 5 cases (83.3%). For the prediction of success in hearing-preservation, factors related to hearing preservation, including preoperative findings of neurotological examination, were analyzed. Postoperative hearing threshold correlated significantly with wave V latency and I-V interpeak latency of preoperative auditory brainstem response (ABR) and the SP/AP ratio of preoperative electrocochleogram and postoperative facial palsy. The size of tumors and preoperative results of speech audiometry did not correlate with hearing results. Postoperative ABR findings were normalized within the observation period from 5 days to 10 months in 3 hearing-preserved patients. Possible mechanisms for improvement of ABR findings after the removal of acoustic neuroma are discussed.

Adult↗
PubMed1994

[A case of dissecting aneurysm associated with mixed connective tissue disease].

A 41 year-old-female with mixed connective tissue disease (MCTD) associated with dissecting aneurysm (DA) of the right posterior cerebral artery is reported. This case satisfied the diagnostic criteria for MCTD, and cerebral angiography revealed the double-lumen sign and pooling of the contrast medium. Thus it was possible to make a definite diagnosis of both MCTD and DA. Fragility of the arterial wall due to the primary disease, MCTD, appeared to have played a role in the occurrence of dissection and the subarachnoid hemorrhage.

Adult↗
PubMed1994

[Estimation of malignancy using SPECT with 201Tl chloride in astrocytic tumors].

This study was designated to estimate the usefulness of SPECT with 201Tl chloride (Tl-SPECT) for the determination of the malignancy in astrocytic tumors. The subjects consisted of 39 astrocytic tumors in supra-tentorial regions. Tl-SPECT undertaken ten minutes to obtain an early image and four hours to obtain a delayed image, after intravenous injection of 74MBq 201Tl chloride (Tl). Tl index (L/N) was defined as the RI count ratio in the tumor lesion (L) to that in the normal parenchyma (N). Histological classification was determined by the WHO grading, and the results showed one case at Grade I, 11 cases at Grade II, 23 cases at Grade III and 4 cases at Grade IV. The proliferating activity was determined by the labeling index using the monoclonal antibody of proliferating cell nuclear antigen (PCNA). In both of the early and delayed images, Tl index was significantly higher (p < 0.01) in high grade astrocytomas compared with low grade tumors. There was a close correlation between the Tl index and the proliferating activity. The relationship between the Tl index and prognosis indicated that the high Tl index was corresponded to the poor prognosis. These results showed that the Tl index is useful to determine the malignancy of astrocytic tumors.

Adolescent↗
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↗