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Biomedical subjects

Y Nakasu

Publications and source records attributed to Y Nakasu.

At least 55 records · Page 3Linked to original sources
PubMed1988

Effects of a new Ca2+ antagonist, KB-2796, on the regional cerebral blood flow and somatosensory evoked potentials in the ischemic brain in cats.

Effects of a new Ca2+ antagonist, 1-[bis(4-fluorophenyl) methyl]-4-(2,3,4-trimethoxybenzyl) piperazine dihydrochloride (KB-2796), on the regional cerebral blood flow (rCBF) and somatosensory evoked potentials (SEPs) were investigated using a model of focal cerebral ischemia in cats. In experiment 1, an occlusion of the middle cerebral artery for 4 hours persistently reduced the ipsilateral rCBF in both the control and the KB-2796-treated groups. However, the flow reduction was much milder in the treatment group than in the control group. Amplitudes of the SEPs diminished in both groups but the rate of deterioration was much slower in the treatment group than in the control group. In experiment 2, an occlusion of the middle cerebral artery for 1 hour was followed by reperfusion for 3 hours. The ipsilateral rCBF decreased during occlusion in both the control and the treatment groups. In the control group, postischemic hyperperfusion was seen in the ectosylvian gyrus after reperfusion, whereas the ipsilateral rCBF recovered rapidly to the control values without showing a phase of hyperperfusion in the treatment group. The rate of recovery of the SEPs was also much more rapid in the treatment group.

Animals↗
PubMed1987

Monitoring of somatosensory-evoked potentials during aneurysm surgery.

Somatosensory-evoked potentials were recorded during and after 31 operations for intracranial aneurysms, and the changes in the central conduction times, namely, the interpeak latencies between the N14 and N20 peaks in response to bipolar stimulation of the median nerve, were studied. Neuroleptanalgesia and routine intracranial operative procedures such as opening the dura mater, drainage of the cerebrospinal fluid, gentle retraction of the brain, and microsurgical dissection of the circle of Willis, were found to have no significant adverse effect on the evoked responses, whereas the temporary clipping of the major cerebral artery or premature rupture of the aneurysm associated with hypotension or both, often caused significant prolongation of the central conduction time. Prolongation of the central conduction time exceeding 1.2 ms or disappearance of the N20 peak adversely affected the postoperative conditions in 8 of 13 patients (62%).

Adult↗
PubMed1987

[Oligodendroglioma of the lateral ventricle--report of 2 cases and a review].

Oligodendrogliomas rarely grow primarily in the ventricles. When compared to more common hemispheric counterparts, such intraventricular oligodendrogliomas, or oligodendrogliomas of the midline group (Martin), present distinct clinical features, namely, (1) they occur in the younger age, (2) an interval between clinical onset and diagnosis or operation is shorter, and (3) initial symptoms are most often limited to those of increased intracranial pressure, although the patient may occasionally present mild organic dementia, callosal disconnection syndrome, and/or mild gait ataxia. Two cases of oligodendroglioma primarily involving the lateral ventricle are reported in female patients, aged 29 and 19, respectively, with sole complaints of an increased intracranial pressure. Magnetic resonance imaging proved to be most useful as a radiologic diagnostic procedure. The tumor was radically removed via a para-falcine transcallosal approach without causing any persistent neurological deficits. Merit and demerit of the approach are briefly discussed.

Adult↗
PubMed1986

Progressive neurological deficits with benign intracerebral cysts. Report of two cases.

Two patients with benign intracerebral cysts are reported and a brief review of the literature is given. Although computerized tomography (CT) scanning is useful in detecting a variety of intracerebral cysts, the CT findings are not specific for any lesion. An exploratory operation with establishment of an adequate route of drainage and a histological examination of the cyst wall are mandatory in the management of patients with a progressive but benign lesion.

Adult↗
PubMed1985

Transient spontaneous regression of mass effect with glioma.

A spontaneous regression of the lesion seen in sequential computertomographic scans does not necessarily indicate a non-neoplastic nature of the pathological process. Two patients with pathologically verified glioma of the brain which showed a temporary regression of the mass effect are reported, and the mechanism of the regression of computertomographic mass signs is discussed.

Aged↗
PubMed1984

Aneurysms of the proximal anterior cerebral artery.

The authors report eight cases of aneurysm of the anterior cerebral artery proximal to the anterior communicating artery (A1 segment). In six of these cases, the aneurysms arose from the proximal anterior cerebral artery at the origin of either a cortical branch (on case), the accessory middle cerebral artery (one case), or a perforating branch (four cases). In another case the aneurysm arose at the proximal end of the fenestration, whereas in the one remaining case no branch was present at the site of the aneurysmal neck.

Aged↗
PubMed1984

Fusiform aneurysm of the anterior communicating artery.

Fusiform aneurysms have often been reported on the internal carotid or vertebrobasilar arteries, but those solely involving the more distal segment of a cerebral artery seem to be exceptional. In a patient harboring two saccular cerebral aneurysms, angiography of the carotid arteries revealed a fusiform dilatation restricted to the anterior communicating artery. At autopsy, this dilatation proved to be a fusiform aneurysm.

Carotid Artery, Internal↗
PubMed1983

Dynamic computed tomography and functional imaging in cerebral vascular anomalies.

Dynamic computed tomography was performed on patients with cerebral vascular anomalies, the density-versus-time curves were derived, and the gray-scale functional images demonstrating the pixel-by-pixel distribution of several flow parameters were processed. This noninvasive method was found to be useful not only in delineating the vascular anomalies with their afferent and efferent vessels, but also in detecting the abnormal flow patterns within and outside the vascular anomalies. Limitations and distinct advantages of this technique are briefly discussed.

Adolescent↗