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N Nakasato

Publications and source records attributed to N Nakasato.

71 records · Page 4Linked to original sources
PubMed1994

[Locating the central sulcus using three dimensional image fusion system of helmet shaped whole head MEG and MRI].

We compared MR anatomy and magnetoencephalographic (MEG) functional methods in locating the central sulcus. In 20 normal volunteers and 58 patients with intracranial structural lesions, the short latency somatosensory evoked magnetic fields for median nerve and posterior tibial nerve stimuli were measured over the entire head, using a helmet shaped MEG system. The dipole positions estimated by a single current dipole model were projected onto the three dimensional MRI. In 94% of a total of 156 hemispheres, N20m dipole positions for median nerve stimuli coincided with the central sulcus defined by MR anatomical image only. For posterior tibial nerve stimuli, the P38m dipole positions were estimated as being near the medial end of the anatomical central sulcus. MRI and MEG are complementary in locating the central sulcus, even in cases of intracranial structural lesions.

Adolescent↗
PubMed1992

Seizure outcome following standard temporal lobectomy: correlation with hippocampal neuron loss and extrahippocampal pathology.

The authors reviewed 149 patients who underwent standard anterior temporal lobectomies for intractable complex partial epilepsy with a mean follow-up period of 5 years. Quantitative analyses of hippocampal neuron loss showed that all patients had some cell loss compared to control hippocampi obtained at autopsy. The average hippocampal cell loss was categorized as severe (greater than 30% of autopsy control levels) or mild. Analysis of hippocampal and extrahippocampal pathologies showed that in 109 cases (73%, the hippocampal lesion group) hippocampal cell loss was mild in 17 cases (16%) and severe in 92 cases (84%); in the remaining 40 cases (27%, the extrahippocampal structural lesion group) hippocampal cell loss was mild in 24 cases (60%) and severe in 16 (40%). The first index of surgical outcome was worthwhile seizure reduction, which occurred in 94 cases (86%) with mild or severe hippocampal lesions and in 33 cases (82%) with extrahippocampal pathology. In the hippocampal lesion group, worthwhile seizure reduction occurred in 90% of cases with severe and in only 65% of cases with mild hippocampal cell loss (p = 0.015). In the extrahippocampal pathology group, worthwhile seizure was not statistically different, whether hippocampal cell loss was severe (94% of cases) or mild (75% of cases). The second index of surgical outcome was the occurrence of residual seizures in the patients with worthwhile seizure reduction, which would indicate remaining epileptogenic tissue. In the hippocampal lesion group, the incidence of residual seizures was not statistically different whether hippocampal cell loss was severe (24% of cases) or mild (45% of cases). However, in the extrahippocampal pathology group, residual seizures occurred in 53% of cases with severe cell loss (dual pathology) but in only 11% of cases with mild cell loss (p = 0.025). Worthwhile seizure reduction can be predicted by the presence of either severe hippocampal cell loss or an extrahippocampal structural lesion. However, residual seizures more frequently follow in cases with a combination of both (extrahippocampal pathology associated with severe hippocampal cell loss, or dual pathology), suggesting that epileptogenic tissue more likely extends outside the boundaries of a standard temporal lobectomy.

Adult↗
PubMed1992

[A case of intracerebral epidermoid associated with aspergillosis].

A case of intracerebral epidermoid associated with aspergillosis, which spread from the middle ear to the left temporal lobe, is reported. A 58-year-old woman was admitted on 6 June 1988, complaining of left temporalgia and motor aphasia. She had suffered from lt. chronic otitis media with cholesteatoma and had undergone a radical operation 11 years previously. CT scan revealed low density area with a mass effect in lt. temporal lobe. Bone image coronal CT scan revealed destruction of the roof of the pyramidal bone had resulted in communication between abscess cavity and external auditory meatus. On MRI scan lt. temporal lobe showed low signal intensity on T1WI, and high signal intensity on T2WI. In spite of strong antibiotic chemotherapy, mass effect on CT scan showed no sign of improvement. We performed total removal of the abscess on 15 July 1987. A number of characteristic aspergillus hyphae were recognized in the resected cyst. As the cyst wall consisted of keratinising squamous epithelium intermingled with granulation tissue, we had a diagnosis of epidermoid cyst. The diagnosis of epidermoid associated with aspergillosis was difficult. CT findings of epidermoid in general, show homogeneous low density without enhancement, but, in our case, CT scan showed heterogeneous low density area with capsular high dense. MRI of epidermoid usually shows a low signal intensity on T1WI, but our case showed iso-low signal intensity on T1WI. In spite of a poor prognosis of aspergillosis of the CNS, our patient has recovered well due to receiving prompt surgical treatment.

Aspergillosis↗
PubMed1991

Surgical treatment of limbic epilepsy associated with extrahippocampal lesions: the problem of dual pathology.

The authors present their review of 178 patients who underwent en bloc temporal lobectomies as surgical treatment for intractable epilepsy. Hippocampal cell density was quantitatively analyzed and the histology of the anterior temporal lobe was reviewed. Fifty-four patients (30.3%) had evidence of extrahippocampal lesions in addition to neuronal cell loss within the hippocampus (the dual pathology group). The pattern of cell loss was analyzed in the remaining 124 cases (69.7%) with no extrahippocampal pathology, and compared with that of the dual pathology group and a control group of four nonepileptic patients. Hippocampal cell loss was found in almost all epileptic patients compared to the control group. Severe cell loss greater than 30% of control values was found in 88.7% of patients without extrahippocampal lesions, but in only 51.8% of patients with dual pathology. The difference between these two groups was statistically significant (p less than 0.001). In the dual pathology group, lesions of different pathology had a significant relationship with the degree of hippocampal cell loss: all 12 patients with glioma had mild cell loss, whereas all 13 patients with heterotopia were associated with severe cell loss. Severity of hippocampal cell loss was also analyzed in relation to seizure history: a prior severe head injury was associated with severe cell loss. Other factors such as seizure duration, secondary generalization, or family history of seizures were not associated with hippocampal damage. Dual pathology may produce a combination of neocortical and temporolimbic epilepsies that warrants a precise definition of the true epileptogenic area prior to surgical treatment.

Adolescent↗
PubMed1990

Magnetic detection of sleep spindles in normal subjects.

The magnetoencephalogram (MEG) and electroencephalogram (EEG) were recorded simultaneously from 3 normal subjects during light sleep. The extracranial magnetic field patterns associated with the ionic currents within the brain (MEG) were measured using a SQUID magnetometer in a magnetically shielded room. Although a previous report indicated that there are few sleep spindles in MEG records, we observed many in all 3 subjects. We believe this is because measurements were made vertically at the vertex region.

Adult↗
PubMed1990

Stereotactic aspiration of thalamic hematoma. Overall results of 75 aspirated and 70 nonaspirated cases.

Among 145 cases of spontaneous thalamic hemorrhage, stereotactic aspiration of the hematoma was done in 75 cases in which the hematoma was greater than 6 ml and the limbs on the affected side could not be elevated. Thirty-one of 40 operated cases with a long axis greater than 3.3 cm were capable of returning to useful activity 6 months postoperatively (excellent to fair). The results 6 months from onset in the 145 cases were as follows: 43% excellent or good, 32% fair, 11% poor and 13% dead. These results appear to indicate that stereotactic aspiration can produce improvements in therapeutic results for cases of thalamic hemorrhage.

Activities of Daily Living↗
PubMed1989

Results of stereotactic aspiration in 175 cases of putaminal hemorrhage.

Believing that improved therapeutic results in cases of intracerebral hematoma might be obtained by minimal invasion of the brain, we used computed tomographic-guided stereotactic aspiration in 175 of 241 patients with putaminal hemorrhage. These patients, who were treated 6 or more hours after onset, had hematomas larger than 8 ml and were unable to raise an arm and/or leg on the affected side. Craniotomy was performed in 15 other patients, most of whom were brought to the hospital with large hematomas within 6 hours of onset. The remaining patients either had mild deficits of consciousness (33 patients) or severe deficits and/or were elderly (18 patients) and were treated conservatively. Thirteen patients (7.4%) showed rebleeding after stereotactic aspiration (6 instances of major and 7 instances of minor rebleeding). Craniotomy and removal of the hematoma were required in three of these patients. Aspiration should be avoided in patients who have a tendency for bleeding, even if mild, because rebleeding occurred in 6 of 23 such patients (26%) in these study. The consciousness level improved in 66 patients (38%), was unchanged in 103 patients (59%), and was worse in 6 patients (3%) 1 week postoperatively. Motor function of the arm improved in 55 patients (31%) and was worse in 23 patients (14%). Six months after surgery, the results for the 175 patients who underwent stereotactic aspiration were: 19% excellent, 32% good, 35% fair, 7% poor, 6% dead, and 1% unknown. For the entire series of 241 patients, the results were: 24% excellent, 26% good, 31% fair, 7% poor, 11% dead, and 1% unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Intracerebral hemorrhage from a metastatic brain tumor. Importance of differential diagnosis preceding stereotaxic hematoma aspiration.

Three cases of sudden intracerebral hemorrhage, which were diagnosed as hemorrhage from metastatic brain tumors following stereotaxic aspiration of a hematoma, are reported. Two cases had subcortical hemorrhage and one had cerebellar hemorrhage. Neither contrast-enhanced computed tomography scans nor angiograms revealed any findings other than those indicating the hematoma in all three cases. However, retrospective study of the anamnesis showed very mild symptoms due to metastasis to the brain or spinal cord in one case each. In cases of intracerebral hematoma located at atypical sites, extreme care is required for the differential diagnosis.

Adenocarcinoma↗
PubMed1988

Influence of liver dysfunction on volume of putaminal hemorrhage.

We studied the relations of age, sex, hypertension, alcohol consumption, liver dysfunction, and thrombocyte count to the volume of the hematoma in 141 patients with spontaneous putaminal hemorrhage. Hematomas were significantly larger in men, regular alcohol consumers, those with liver dysfunction, and those with low platelet counts. Our findings reflect the fact that almost all of the alcohol consumers were men, most of them had liver disorders, and the volume of hematoma in such patients was relatively large.

Adult↗
PubMed1988

[CT-guided stereotaxic implantation of the Ommaya reservoir for cystic brain tumors].

We report the use of CT-guided stereotaxic system to implant Ommaya reservoir in 26 patients with cystic brain tumors consisting of 16 gliomas, 3 craniopharyngiomas, 3 metastatic brain tumors and 5 other and unknown pathologies, on the way of their biopsy. The entire procedure was carried out in the CT room using Leksell's CT stereotaxic system. In 24 cases with supratentorial tumors, it was at the option of the operator to take any approach such as frontal, posterior temporal and parietal approaches. Especially in 3 cases of craniopharyngioma, we inserted the tube into their cyst directly so that the ventricle should not be open to the cyst. Also in cases of a pontine glioma and a C-P angle metastatic tumor, we used retromastoid approach to the posterior fossa by making patient's heads turned about 30 to 40 degrees to contralateral side of the approach, with slight flexion of the neck. Minimal bleeding occurred during operation in one case, however, it showed no clinical symptoms. Advantages of this method are as follows: Operative invasion is minimal; The surgeon can check the course of the cannula and position of the tip of Ommaya tube even at operation, and can modify it, if necessary.

Adolescent↗
PubMed1988

[CT-guided stereotaxic biopsy in 104 cases of brain tumor].

Biopsy of suspected brain tumor was performed on 104 cases using Leksell's CT-guided stereotaxic system. The entire operation was performed in the CT room. A Backlund's spiral biopsy needle was advanced to the target point in a stepwise fashion and two to nine tissue samples were obtained from one to three biopsy tracks. Tissue sampling was impossible in two cases because the tumors were too hard for biopsy needle to advance. Also, sampling was sometimes difficult in the case of soft and necrotic tumor, cystic tumor, already treated (irradiated) tumor and the lesion including old blood clot. After the biopsy, minimal bleeding occurred in nine cases, however, stopped within 10 minutes by controlling the blood pressure. A minimum sized hematoma was visible on the postoperative CT in four cases. Postoperative neurological deterioration was seen in two cases. One case was transient and the other seemed to be in his natural course. Anyway, there were neither cases of operative mortality nor severely complicated cases in these series. Useful pathological diagnosis was possible in 83 cases (80%). Accurate diagnosis was not possible in the remaining 21 cases, however, their histological datum such as necrosis, blood clot, and so on were very useful to estimate the lesions. In summary, accurate diagnosis rate of CT-guided stereotaxic needle biopsy was 80%. However, it appeared to be a safe and useful procedure in the diagnosis of intracranial mass lesions.

Adult↗
PubMed1987

[A case of von Hippel-Lindau disease showing only spinal cord symptoms].

A rare case of von Hippel-Lindau disease showing only spinal cord symptoms is reported. This 18-year-old boy was admitted to our clinic because of urinary disturbance, slowly progressive muscle weakness and sensory disturbance of his body and four extremities. Myelography demonstrated an expanding spinal cord and a figure of complete block of contrast medium at the lower cervical level. Dilated syrinx below the level of Th-3 was shown by delayed scan (19 hr.) of metrizamide CT myelography. These findings suggest that metrizamide could pass through the cord substance from the subarachnoid space into a syrinx cavity. Contrast enhancement CT scan revealed a slightly high density mass lesion at the level of Th-1 and a more marked tumor stain at the level of C-5 and 6. Syringo-subarachnoid shunt was done but the spinal intramedullary tumors were so deeply situated in the spinal cord that total removal of them was abandoned. The pathological diagnosis was hemangioblastoma. There were also a hemangioma at the right retina and multiple small tumor stains in the cerebellum, but they presented no clinical symptoms.

Adolescent↗
PubMed1975

Studies of ultramicrostructure in relation to disaccharidase activity in the jejunal mucosa.

Ultramicrostructural changes of the mucosa of the small intestine were studied in relation to the alterations of the lactase activity, measuring the height of microvilli by electron microscopy and the enzyme activity by the method of Dahlqvist. Studies with clinical cases revealed that the height of microvilli correlated with the lactase activity significantly (p less than 0.01), and that patients with relatively higher microvilli had a correspondingly higher activity of lactase. In animal experiments an increase of lactase activity by lactose load feeding and low calorie feeding resulted in a raise in the height of microvilli. It was concluded that lactase deficiency in adults and in various gastrointestinal diseases, where no histological abnormality was observed by light microscopy is perhaps due to shortening of the microvilli of the mucosa. It was speculated that the microvillous change and the sequential hypolactasia may be the initial ultramicrostructural and enzymatic alteration in the diffuse disease of the small intestine.

Adult↗