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Biomedical subjects

E Nakai

Publications and source records attributed to E Nakai.

At least 19 recordsLinked to original sources
PubMed2001

Combined surgery and endovascular stenting for basilar artery stenosis refractory to balloon angioplasty: technical case report.

The authors report a case of symptomatic basilar artery stenosis treated by stenting via the surgically exposed C1 vertebral artery. This case was initially treated by percutaneous transluminal angioplasty via a transfemoral route but resulted in unsatisfactory dilatation. Stenting via a transfemoral route also resulted in failure because of the coiling of the proximal vertebral artery. Direct puncture of the vertebral artery beyond the coiling portion was tried but a stent could not be delivered beyond the C2 vertebrae. Finally, the vertebral artery was surgically exposed between C1 and the occipital bone and a stent was introduced into the lesion from this portion under fluoroscopic control. The basilar artery was fully opened by stenting without new neurological deficits. Stenting of the basilar artery via a transfemoral route is not always possible even with newer generation stents if the vertebral artery has elongated tortuous curves. Combined surgery and endovascular stenting is one of the alternatives in such cases including our case.

Aged↗
PubMed2001

Jargonagraphia with severe aphasia due to a right hemisphere lesion: case report.

The authors report a case of a patient who developed jargonagraphia, severe aphasia, unilateral spatial neglect and apraxia due to a right hemisphere lesion. Jargonagraphia with severe aphasia, unilateral spatial neglect and apraxia is quite rare. The mechanisms of jargonagraphia remain unknown. A possible mechanism underlying this case of jargonagraphia is discussed.

Agraphia↗
PubMed1999

Gas chromatography/principal component similarity system for detection of E. coli and S. aureus contaminating salmon and hamburger.

Coho, Atlantic, Spring, and Sockeye salmon and five commercial samples of hamburger patties were analyzed by processing gas chromatography (GC) data of volatile compounds using the principal component similarity (PCS) technique. PCS scattergrams of the samples inoculated with Escherichia coli and Staphylococcus aureus followed by incubation showed the pattern-shift lines moving away from the data point for uninoculated, unincubated reference samples in different directions with increasing incubation time. When the PCS scattergrams were drawn for samples incubated overnight, the samples inoculated with the two bacterial species and the uninoculated samples appeared as three separated groups. This GC/PCS approach has the potential to ensure quality of samples by discriminating good samples from potentially spoiled samples. The latter may require further microbial assays to identify the bacteria species potentially contaminating foods.

Animals↗
PubMed1999

Peptide based interleukin-1 beta converting enzyme (ICE) inhibitors: synthesis, structure activity relationships and crystallographic study of the ICE-inhibitor complex.

Based on the X-ray structure of the complex of Ac-Tyr-Val-Ala-Asp-H (L-709049) and interleukin-1 beta converting enzyme (ICE), we synthesized compounds which were derived from 2-NapCO-Val-Pro-Asp-CH2OPh (1) to obtain a potent inhibitor in the cell assay. Among these compounds, (3S)-N-methanesulfonyl-3-[[1-[N-(2-naphthoyl)-L-valyl]-L-prolyl]amino]- 4-oxobutanamide (27c) showed high potency not only in the enzyme assay but also cell assay with IC50 values of 38 nM and 0.23 microM, respectively. Compound 27c, with a c log P value of 1.76, had a more hydrophilic character compared with 1. Compound 27c also dose dependently inhibited LPS-primed ATP-induced IL-1 beta release in mice. The crystal structure of the complex of compound 27c and ICE revealed that compound 27c had further interactions with ICE in the naphthoyl group at the P4 position and in the methyl group of the methanesulfonamidecarbonyl group at the P1 position, compared with L-709049. To our knowledge, compound 27c is the first example that shows a strong inhibitory activity without the carboxyl group at the P1 position.

Animals↗
PubMed1999

Ablation of the subthalamic nucleus supports the survival of nigral dopaminergic neurons after nigrostriatal lesions induced by the mitochondrial toxin 3-nitropropionic acid.

We investigated the role of the excitatory afferents from the subthalamic nucleus (STN) in the death of nigral dopamine (DA) neurons after nigrostriatal axon terminal lesions. Nigral DA neurons were detected by use of both tyrosine hydroxylase immunolabeling or retrograde labeling of nigral cells with fluorogold. Sprague-Dawley rats were subjected to unilateral, quinolinic acid-induced destruction of the STN. Sham lesions of the STN were made by injecting phosphate-buffered saline. Two weeks after STN ablation, lesions of nigrostriatal DA neurons were induced by intrastriatal injections of either the mitochondrial toxin 3-nitropropionic acid (3-NP) or the catecholamine toxin 6-hydroxydopamine (6-OHDA). Intrastriatal injections of 3-NP or 6-OHDA caused a progressive loss of nigral tyrosine hydroxylase-positive or fluorogold-labeled DA neurons in a dose-dependent manner. Previous ablation of the STN significantly attenuates the loss of DA neurons in rats receiving 3-NP but not 6-OHDA. Sham lesions of the STN did not affect DA neuron death induced by the toxins. The results indicate that the excitatory inputs from the STN may contribute to the death of nigral DA neurons under a condition of 3-NP-induced metabolic impairment.

Animals↗
PubMed1999

[Choroid plexus papilloma in the posterior third ventricle in infancy: a case report].

Choroid plexus papillomas represent approximately 0.5% of all intracranial tumors, but they are found in the third ventricle only infrequently. We report a case of choroid plexus papilloma in the third ventricle which is difficult to differentiate from a pineal region tumor. A 4-month-old female presented with bulging fontanelle and sunset phenomenon. A CT scan and MRI showed marked hydrocephalus caused by a tumor extending from the posterior third ventricle to the peneal body. Preoperatively, we diagnosed the lesion as a pineoblastoma. The tumor was totally removed through the occipital transtentorial approach. Pathological examination of the tumor revealed a typical choroid plexus papilloma. The operation was uneventful, and she has grown normally without recurrence of the tumor for three years since the operation. A sagittal gadolinium-enhanced MRI was useful in our case to differentiate a choroid plexus papilloma from a pineal region tumor, because the former extended into the aqueduct forming the shape of the letter V while the latter compressed the aqueduct downward.

Cerebral Ventricle Neoplasms↗
PubMed1998

Percutaneous transluminal angioplasty for intracranial arteriosclerotic lesions.

We report 17 cases of intracranial arterial stenosis treated by percutaneous transluminal angioplasty (PTA), including 9 on the intracranial internal carotid (ICA), 4 on the middle cerebral (MCA), and 4 on vertebrobasilar artery (VBA) system. All patients had ischaemic brain symptoms and stenoses of more than 60% (calculated angiographically). We treated four patients by PTA for residual stenoses after thrombolysis for acute occlusion. We used PTA balloon catheters 2.0-3.5 mm in diameter for all procedures. As a rule, the balloon was inflated for 1 min at 6 atm. All arteries were successfully dilated (stenosis less than 50%) except for one treated by PTA for residual MCA stenosis after thrombolysis. The patient died of a massive infarct due to MCA reocclusion caused by arterial dissection. Stenosis recurred in 4 of 16 patients. Repeat PTA was successfully carried out in these cases. However, stenosis recurred in one of these patients 3 months after PTA, but the patient is being followed because he is asymptomatic. PTA of intracranial arteries is effective, but its indications should be based strictly on potential risks, such as acute occlusion derived from arterial dissection.

Aged↗
PubMed1997

Transplantation of autologous sympathetic ganglion into the brain with Parkinson's disease. Long-term follow-up of 35 cases.

Transplantation of autologous sympathetic ganglion was performed in 35 patients with Parkinson's disease. Approximately half the patients showed improvement of parkinsonian symptoms over the 3 years following transplantation. The patients showed amelioration of bradykinesia and gait disturbance, but tremor and muscle rigidity were not improved by transplantation. The other half of the patients did not show amelioration after transplantation. No serious complications were encountered, though mild ptosis was observed in all patients. The mechanism of improvement of symptoms might be the release of dopamine from the grafted sympathetic ganglion. Transplantation of autologous sympathetic ganglion can be a therapeutic modality for Parkinson's disease.

Adult↗
PubMed1997

Iatrogenic arteriovenous fistula of the middle meningeal artery caused during embolization for meningioma--case report.

A 73-year-old female developed middle meningeal arteriovenous fistula during embolization of a falx meningioma. The cause of this complication was thought to be perforation by the guide wire during catheterization at the sharp bend in the sphenoidal portion of the middle meningeal artery. Embolization of the fistula and the feeding artery to the meningioma with polyvinyl alcohol particles 250-355 microns size resulted in complete obliteration of the fistula. Computed tomography showed no epidural or subdural hematoma. Introduction of the microcatheter beyond the sharp bend in the middle meningeal artery should not be attempted to avoid the possibility of iatrogenic middle meningeal arteriovenous fistula.

Aged↗
PubMed1996

Transluminal angioplasty for arteriosclerotic disease of the distal vertebral and basilar arteries.

OBJECTIVE: Percutaneous transluminal angioplasty (PTA) for the distal vertebral and basilar artery is now being performed in selected patients with haemodynamically significant lesions of the posterior cerebral circulation. Its effect and overall results were examined. PATIENTS AND METHODS: A balloon dilatation catheter specifically developed for these procedures, with a 2.0-3.5 mm balloon diameter, at 6 atmospheres of pressure, was used. Angioplasty was performed in 12 patients (including six whose initial results have been reported) with angiographically documented stenotic lesions involving either the intracranial vertebral artery (C1-C2 portion) or the basilar artery, and satisfying the following criteria: (1) clinical symptoms suggestive or consistent with a transient ischaemic attack refractory to medical treatment, or small infarction of the posterior circulation; and (2) angiographically documented stenosis greater than 70%. Two of 12 patients had complete thrombosis of the distal vertebral and basilar artery and PTA was performed after successful intra-arterial thrombolysis. RESULTS: Successful results, without complications, were obtained in eight patients, with complete resolution of vertebrobasilar ischaemic symptoms. Immediate complications occurred in four patients including two with vessel dissection, and two with thromboembolism. The two patients with acute arterial dissection were reoperated but developed small infarctions with permanent neurological deficits. The two patients with thromboembolic complication showed transient neurological deficit. The overall stenosis ratio decreased from a mean of 84% pretreatment to 44% after the angioplasty procedure. Restenosis occurred in two patients. Long term clinical follow up in 11 patients who survived more than six months showed resolution of ischaemic symptoms after PTA in all except for one with a restenosis who had recurrent transient ischaemic attacks. CONCLUSION: Transluminal angioplasty may be an effective procedure to treat vertebrobasilar ischaemia secondary to high grade arteriosclerotic disease affecting either the distal vertebral or basilar artery regions that do not respond to medical treatment.

Acute Disease↗
PubMed1996

[Super selective amytal test for functional evaluation of the brain--a less invasive functional test].

In the neurosurgical field, it is very important to evaluate localized function of the affected region preoperatively. In order to investigate lateralized and localized brain function, we have developed an alternative to the original Wada test, and refer to it as the super selective amytal test (SSAT). We performed super selective catheterization of the target artery after conventional carotid angiography, injected Amytal (amobarbital, 30-100 mg) through a micro-catheter, and identified potential local function. In ten cases, including AVM, aneurysm, and brain tumor, we investigated localized function of the affected site preoperatively by SSAT, and chose our treatment based on the results of this test. There was a good correlation between the results of the SSAT and the results of surgery in every case. There were no prolonged neurological complications of this test. Evaluation of the results of the SSAT should be interpreted under precise DSA control, since blood flow in the brain differ among individuals. This test may contribute to our knowledge of localized function in the cerebral cortex and deep brain areas in neurosurgical patients.

Adult↗
PubMed1995

[Endovascular treatment of cerebral vasospasm with intra-arterial papaverine infusion].

Thirty-one cases of cerebral vasospasm following subarachnoid hemorrhage were treated with intraarterial papaverine infusion. Symptomatic cases were nineteen, and asymptomatic cases were twelve. Papaverine (120 mg/saline 50 ml, 30 min) was injected superselectively to vasospastic vessels through a microcatheter. The rate of symptomatically improved cases was 63% initially, but about two thirds of those cases had recurrence within a day. The 63% of symptomatic cases showed infarction in spite of papaverine infusion. Three cases of recurrent vasospasm after intra-arterial papaverine underwent PTA and showed good dilatation of vasospastic vessels. The complications of our intra-arterial papaverine were hypotension in two cases, convulsion in one case and transient disturbed consciousness in one case. We experienced no fatal complications. Overall outcome was ADL1 (19%), ADL2 (25%), ADL3 (44%), ADL4 (0%), ADL5 (6%), and death (6%). Since the effect of intra-arterial papaverine infusion is of short duration and weak, combination of PTA and papaverine may be necessary. It is recommended to use papaverine for vasospasm in distal arteries such as M2, A1, A2, and to carry out PTA for proximal arteries such as ICA and M1.

Adult↗
PubMed1995

[Effects on cognitive function and activities of daily living after stereotactic thalamotomy for Parkinson's disease].

Stereotactic thalamotomy was performed in ten patients with Parkinson's disease for the suppression of their tremor. After VL-thalamotomy, contralateral tremor and rigidity disappeared or was significantly reduced. Activities of daily living (ADL) measured by functional independence measure and Parkinson's disability score were improved postoperatively in all patients. There was significant improvement in anxiety index. However, other neuropsychological tests showed no significant change postoperatively. ADL improved after thalamotomy. It is concluded that stereotactic VL-thalamotomy is a useful treatment which improves ADL without cognitive dysfunction.

Activities of Daily Living↗
PubMed1994

Studies on beta-lactam antibiotics. IV. An improved synthesis of 3-(isothiazolylthiomethyl)cephalosporins and its application to new derivatives.

An improved synthesis and in vitro activity of cephalosporins with a (4-carboxy-3-hydroxy-5-isothiazolyl)thiomethyl group at the 3-position and its application to the preparation of new derivatives are described. These compounds showed excellent activity against Gram-negative bacteria including beta-lactamase producing strains. Among them, 2f was the most interesting because of its broad spectrum of antibacterial activity, including Gram-positive bacteria, and its outstanding inhibitory potency against Pseudomonas aeruginosa.

Animals↗
PubMed1993

Acute subdural hematoma associated with vacuolated meningioma--case report.

A 67-year-old male presented with a left temporal convexity vacuolated meningioma associated with acute subdural hematoma manifesting as sudden headache, nausea, and vomiting without neurological deficit. Magnetic resonance imaging disclosed an extra-axial mass as mixed low- and high-signal intensities and a crescent high-intensity area in the left convexity. Histological examination diagnosed meningotheliomatous meningioma with vacuolated components and hemorrhagic foci. The tumor and hematoma were removed without postoperative complications.

Aged↗
PubMed1991

[Acute subdural empyema due to peptostreptococcus].

A very rare case of acute subdural empyema due to peptostreptococcus was reported. A 11-year-old-girl was admitted to our hospital with high grade fever, unconsciousness and rt hemiparesis. CT scans showed the mass effect caused by the subdural empyema over the left frontotemporal region. Subdural empyema was evacuated by the craniotomy. Peptostreptococcus was found in the pus obtained during the operation. However, CT scans 10 days after the operation revealed another subdural empyema in the left frontal base and interhemispheric fissure, which was removed again by the craniotomy using coronal incision 14 days after the first operation. Frontal sinusitis was also demonstrated by CT scan. Killian's operation to the frontal sinusitis was performed by otorhinolaryngologists at the same time. Six weeks after the second operation, she was discharged without any neurological deficits. Peptostreptococcus is one of the indigenous microflora of the oral cavity, skin, gastrointestinal tract and genitourinary system and may be a causative microorganism in every type of human infection due to its abnormal localization. There is a controversy concerning surgical management subdural empyema. Both the burr hole drainage of pus and the craniotomy are advocated. Associated otorhinologic lesions must not be overlooked. Otorhinologic consultation should immediately be obtained so that the drainage of an infected paranasal or mastoid sinus can be performed at the time of craniotomy. This is critical to prevent the recurrence of the subdural empyema from further extension of the extracranial disease.

Acute Disease↗