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Biomedical subjects

T Itakura

Publications and source records attributed to T Itakura.

At least 55 records · Page 3Linked to original sources
PubMed1999

Presumed intraventricular meningioma treated by embolisation and the gamma knife.

A 58-year-old woman with a presumed incidentally discovered meningioma in the left lateral ventricle was treated by superselective embolisation and gamma knife therapy. The diameter of the tumour was 40 mm, and its main feeding artery was the left lateral posterior choroidal artery. This vessel was embolised with microcoils. At 8 months following embolisation, the diameter of the tumour had decreased and was stable. The gamma knife was chosen as an adjuvant therapy for the further control 13 months after embolisation. Embolisation and gamma knife therapy may be an alternative treatment for meningiomas where surgical resection appears difficult.

Cerebral Ventricle Neoplasms↗
PubMed1999

Endovascular stent placement for cervical internal carotid artery aneurysm causing cerebral embolism: usefulness of neuroradiological evaluation.

We present a case of a cervical internal carotid artery aneurysm that caused cerebral embolism. This lesion was supposed to be a dissecting aneurysm due to blunt neck injury. The large aneurysm with intramural thrombus was treated with endovascular placement of a balloon-expandable stent. Both CT and MRI were useful for evaluating the size and characteristics of the aneurysmal wall. Intravascular ultrasound imaging was also useful for evaluation of the satisfactory stent deployment and identification of the neck of the aneurysm. We discuss effectiveness of endovascular stenting for cervical internal carotid artery aneurysm with intramural thrombus and the usefulness of a combination of the neuroradiological imaging before, during and after the interventional procedure.

Adult↗
PubMed1999

Embryonic striatal grafts restore neuronal activity of the globus pallidus in a rodent model of Huntington's disease.

It has been demonstrated in rats that embryonic striatal grafts placed in the excitotoxically lesioned striatum establish neuronal connections with the host globus pallidus. In order to determine whether the morphologically verified connections between the grafts and host are functional, the present study investigated the effects of embryonic striatal grafts on changes in the neuronal activity of the globus pallidus in rats with quinolinic acid-induced striatal lesions. The activity of pallidal neurons was determined by use of quantitative cytochrome oxidase histochemistry and an electrophysiological technique. Striatal lesions induced an increase in both the cytochrome oxidase activity and the spontaneous firing rate of the globus pallidus ipsilateral to the lesions. Grafts derived from the lateral ganglionic eminence, but not the medial ganglionic eminence, reversed the lesion-induced increase in the cytochrome oxidase activity of the globus pallidus with concomitant reduction of apomorphine-induced rotational asymmetry. The lateral ganglionic eminence grafts also attenuate the increase in the firing rate of pallidal neurons in rats with striatal lesions. The present results provide evidence that striatal lesions lead to the loss of a tonic inhibitory input to the globus pallidus with consequent increase in the activity of pallidal neurons, and that intrastriatal striatal grafts reverse the altered activity of pallidal neurons. The findings strongly suggest that embryonic striatal grafts functionally repair the damaged striatopallidal pathway.

Action Potentials↗
PubMed1999

A case of amnestic syndrome caused by a subcortical haematoma in the right occipital lobe.

A case of an amnestic syndrome caused by a subcortical haematoma in the right occipital lobe is reported. A 62-year-old right-handed man presented with a sudden onset of headache to the hospital. On admission, he had a left homonymous hemianopsia, disorientation and recent memory disturbance, but had normal remote memory and digit span. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a subcortical haematoma in the right occipital lobe. These findings suggest that the patient's amnesia was caused by a lesion of the retrosplenial region in the non-dominant hemisphere.

Amnesia↗
PubMed1999

[Construct validity of a new computer-assisted cognitive assessment battery in normal adults].

A computer-assisted battery for neuropsychological tests (CNT) has been designed to screen adults for cognitive impairment. The aim of this study was to gather evidence for the construct validity of CNT and also investigate the relationship between CNT and conventional neuropsychological tests. Subjects were 45 healthy adults (21 men and 24 women), who ranged in age from 20 to 70 years (mean = 33.5, SD = 1.9) with no history of substance abuse, or of psychotic or neurological disorders. The CNT in our study consists of six subtests designed to assess various components of driving, such as digit span, visual scanning, visual and verbal memory, complex reaction time, and vigilance. Mini-mental state test, Kana-hiroi test, word fluency, the auditory-verbal learning test and Raven's colored progressive matrices were also performed as conventional neuropsychological tests. Results showed there were high correlations between each CNT subtests and conventional neuropsychological tests. A factor analysis (with varimax rotation) identified 4 factors with eigen values greater than 1, which accounted for over 70% of the variance. CNT was able to estimate each factor related to cognitive function such as learning and memory, attention, judgment, and visual scanning selectively. CNT may thus be a useful tool for detection of cognitive impairment, although this test has important limitations. Broader applications of these tests will require extensive population-based validation.

Adult↗
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

The C-terminal domain of p53 catalyzes DNA-renaturation and strand exchange toward annealing between intact ssDNAs and toward eliminating damaged ssDNA from duplex formation through preferential recognition of damaged DNA by a duocarmycin.

The C-terminal domain of p53 may bind single-stranded (ss) DNA ends and catalyze renaturation of ss complementary DNA molecules, suggesting a possible direct role for p53 in DNA repair (Proc. Natl. Acad. Sci. USA, 92, 9455-9459, 1995). We found that DU-86, a duocarmycin derivative which alkylates DNA, bound ssDNA and enhanced the DNA binding activity of the p53 C-terminus. DU-86 weakened p53-mediated catalysis of complementary ssDNA renaturation. p53 C-terminus catalyzed DNA strand transfer toward annealing between intact ssDNAs and toward eliminating DU-86-damaged ssDNA from duplex formation. These results suggest that p53, via the C-terminal domain, may play a direct role in DNA repair by preferential recognization and elimination of damaged DNA.

Antineoplastic Agents, Alkylating↗
PubMed1998

Intrastriatal mesencephalic grafts affect neuronal activity in basal ganglia nuclei and their target structures in a rat model of Parkinson's disease.

Nigrostriatal dopamine (DA) lesions lead to changes of neuronal activity in basal ganglia nuclei such as the globus pallidus (GP, the rodent homolog of lateral globus pallidus), entopeduncular nucleus (EP, the rodent homolog of medial globus pallidus), substantia nigra pars reticulata (SNR), and subthalamic nucleus (STN). We investigated in rats whether embryonic mesencephalic DA neurons grafted in the striatum may affect the lesion-induced alterations of neuronal activity in these structures. Regional neuronal activity was determined by use of quantitative cytochrome oxidase histochemistry. It was also examined in lesioned rats whether the grafts may regulate the expression of c-Fos after systemic administration of apomorphine in the basal ganglia nuclei as well as their target structures, including the ventromedial thalamic nucleus (VM), superior colliculus (SC), and pedunculopontine nucleus (PPN). Lesioned rats exhibited an increased activity of CO in the GP, EP, SNR, and STN ipsilateral to the lesion. Intrastriatal nigral grafts reversed the increases in the CO activity in the EP and SNR, whereas the grafts failed to affect the enzyme activity in the GP or STN. Apomorphine induced an increased expression of c-Fos in the GP, STN, VM, SC, and PPN on the lesioned side. The enhanced expression of this protein in all the structures except for the STN was attenuated by nigral grafts. The present results indicate that intrastriatal DA neuron grafts can normalize the lesion-induced changes of neuronal activity in the output nuclei of the basal ganglia as well as their target structures.

Animals↗
PubMed1998

Changes in the mitochondrial enzyme activity in striatal projection areas after unilateral excitotoxic striatal lesions: partial restoration by embryonic striatal transplants.

It is well established that the activity of cytochrome oxidase (CO), a mitochondrial enzyme, reflects the long-term, steady-state levels of neuronal activity. The present study investigated the long-term effects of unilateral striatal lesions induced by quinolinic acid on CO activity in primary striatal targets, including the globus pallidus (GP), entopeduncular nucleus (EP), and substantia nigra pars reticulata (SNR) and a secondary striatal projection area, such as subthalamic nucleus (STN), in rats. The activity of CO was determined by measuring staining intensity on brain sections processed for CO histochemistry. We also examined whether intrastriatal transplants of embryonic striatal tissue could affect the lesion-induced changes in the CO activity of those brain structures. Unilateral striatal lesions were found to lead to increases in the CO activity of the GP, EP, and SNR ipsilateral to the lesions. By contrast, the activity of the ipsilateral STN was decreased following striatal lesions, probably due to the increased inhibitory effect of the GP on the STN. Intrastriatal implantation of the lateral ganglionic eminence (LGN), but not the medial ganglionic eminence (MGE), reversed the lesion-induced changes in the CO activity of the GP and STN with concomitant attenuation of apomorphine-induced rotational asymmetry. The grafts failed to affect the activity of either the EP or SNR. The present results indicate that striatal lesions induce changes in the functional activity of basal ganglia nuclei and that the LGE grafts placed in the damaged striatum partly reverse the alterations in the functional state of the basal ganglia circuitry.

Animals↗
PubMed1998

Magnetic resonance signal intensity and volume changes after endovascular treatment of intracranial aneurysms causing mass effect.

To determine when and how intracranial aneurysms causing mass effect change following endovascular treatment, we used MRI to assess patients for 2-3 years after the interventional procedure. Nine patients who had aneurysms compressing the surrounding structures underwent endovascular treatment. Proximal occlusion of the parent artery was performed in seven cases, and in two the aneurysm was embolised with microcoils. After embolisation, signal intensity within aneurysms tended to be high on both T1- and T2-weighted images. When there was rapid reduction in size high-signal zones within aneurysms became isointense or gave low signal on T1-weighted images. On T2-weighted images, isointense or low-signal foci appeared within high-signal areas in the aneurysm, giving mixed intensity. In typical cases, the mean volume of the aneurysm fell to approximately 30% of its initial value 2-12 months after treatment. After this, no additional reduction was observed. The aneurysms which showed little signal intensity change tended to shrink more slowly and to a lesser degree than the more typical cases. Aneurysms which gave high signal on both T1- and T2-weighted images early following embolisation shrank more quickly than those showing little signal change.

Adult↗
PubMed1998

Carotid endarterectomy and simultaneous percutaneous transluminal angioplasty for tandem internal carotid stenoses.

We treated three patients with tandem internal carotid stenoses in single procedures including carotid endarterectomy (CEA) for the proximal stenosis and percutaneous transluminal angioplasty (PTA) for the distal stenosis. We devised a Y-shaped shunt tube for the CEA, through which a balloon catheter was introduced to perform PTA guided by mobile digital subtraction angiography. No cerebrovascular events occurred during follow-up. Our approach avoids the risk of a second procedure while effectively treating tandem stenoses.

Aged↗
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↗
PubMed1998

Gerstmann's syndrome associated with chronic subdural haematoma: a case report.

We report a patient who exhibited Gerstmann's syndrome in association with a chronic subdural haematoma. A 71-year-old right-handed woman presented with mild right arm and leg weakness that began 2 weeks prior to admission. Neurological examination on admission revealed a mild right hemiparesis. Neuropsychological examination revealed right-left disorientation, finger agnosia, agraphia, and acalculia, but no language disturbance. A computerized tomographic (CT) scan revealed a large left frontoparietal, extra-axial hypodense fluid collection containing scattered hypodense foci. A left parietal evacuation of the haematoma was performed. Following surgery the patient dramatically improved. We suggest that the direct compression by the chronic subdural haematoma or a hemispheric pressure difference caused Gerstmann's syndrome. This is an unusual report of a Gerstmann's syndrome following chronic subdural haematoma.

Aged↗
PubMed1998

[When do strokes occur?--analysis of diurnal variation and activity during the onset].

The diurnal variation and activity during the onset of stroke were examined in more than 700 consecutive patients. 304 cases with hypertensive intracerebral hemorrhage (HIH), 214 cases with subarachnoid hemorrhage (SAH) and 201 cases with obstructive cerebrovascular disease (OCVD) were investigated about the time of onset. Concerning the activity during the onset, 296 cases with HIH, 215 cases with SAH and 198 cases with OCVD were examined. HIH occurred frequently between 1500-1800 hours, 0600-0900 hours and 1800-2100 hours. SAH occurred frequently between 0900-1200 hours, 1500-1800 hours and 1800-2100 hours. Both HIH and SAH were least likely to occur between 0000-0300 hours. OCVD exhibited a small peak incidence between 0900-1200 hours, but there were no differences between the groups for the other time periods. Both HIH and SAH were likely to occur frequently in the lavatory, while bathing and during meals. HIH also occurred frequently during physical work, while SAH occurred as frequently during mental work or housework as during hard physical labor. OCVD commonly occurred during sleep or relaxation. The relationship between diurnal variation in stroke and the circadian variation of blood pressure is discussed. The incidence of all three types of strokes during work was higher in the non-aged group (patients under 66 years) than in the aged group (patients over 66 years). HIH and SAH occurred associated with alcohol consumption more frequently in the non-aged group than in the aged group. It is likely that the difference of the time and of the activity during the onset between aged group and non-aged group reflects the difference of life-style between aged and non-aged people.

Activities of Daily Living↗