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Y Yonemasu

Publications and source records attributed to Y Yonemasu.

At least 19 recordsLinked to original sources
PubMed1992

Effects of intracarotid infusion of neuropeptide Y on cerebral blood flow in rats.

Neuropeptide Y (NPY) was continuously administered to Wistar rats intracarotidly via the external carotid artery and local cerebral blood flow (LCBF) was measured by a quantitative autoradiography using [14C]iodoantipyrine. A remarkable reduction in LCBF was observed in the NPY infused hemisphere. This depression was irregular and was particularly evident in the hippocampus, selective thalamic nuclei and the cerebral cortex.

Animals↗
PubMed1992

Cerebral blood flow and histopathological changes following permanent bilateral carotid artery ligation in Wistar rats.

Cerebral blood flow and histopathological changes after bilateral carotid artery ligation (BCAL) in Wistar rats were studied. Eight of the 38 rats (21%) died within one week. In the 30 survivors, the incidence of histopathological change was 90% in the caudate nucleus, 23% in the cortex, 30% in the hippocampus, and 0% in the other structures. Local cerebral blood flow (LCBF) was measured using the quantitative autoradiographic 14C-iodoantipyrine technique in 24 anatomically discrete regions of the brain. BCAL induced ischemia in the entire forebrain. The percent reduction of LCBF was between 25-94% of the control at 2.5 h after BCAL. LCBF tended to recover 1 week after BCAL except for the regions of neuronal damage. These results suggest that neuronal damage does not correlate with the flow rate. In the present study, selective neuronal damage was also observed in rats with chronic cerebral ischemia.

Animals↗
PubMed1992

Kainic acid-induced thalamic seizure in cats--a possible model of petit mal seizure.

Bipolar depth electrodes were implanted stereotaxically in the thalamus, hippocampus and midbrain reticular formation of cats. Cortical screw electrodes were placed over the bilateral sensorimotor cortex. A guide cannula with an inner injection cannula was inserted unilaterally into the posterolateral ventral nuclei (VPL) of the thalamus. Eight days after the procedures, kainic acid (2.0 micrograms) was injected unilaterally into the VPL via the injection cannula in freely moving animals and electro-clinical observations were made. About 1 h after the kainic acid injection, multiple spikes were observed in the VPL (injection site), which propagated to the subcortical structures. These seizures finally propagated bilaterally to the cortex about 2 h after the injection. About 3-4 h after the injection, small spike and wave complexes repeatedly appeared for a short period of time in cortical leads and cats exhibited behavioral arrest with unresponsiveness during the seizures. About 24 h after the injection, generalized small spike and wave complexes were observed intermittently in cortical and subcortical structures. They persisted for 4-5 s and were associated with behavioral arrest and staring. The results demonstrate that a unilateral microinjection of kainic acid into VPL induced petit mal-like seizure, and suggest that VPL plays an important role in the generation or transfer of spike and wave complexes.

Animals↗
PubMed1992

The effects of oxiracetam (CT-848) on local cerebral glucose utilization after focal cerebral ischemia in rats.

The effects of oxiracetam on the reduction of brain metabolism induced by focal cerebral ischemia were investigated by measuring local cerebral glucose utilization (LCGU) in rats 24 hr after left middle cerebral artery occlusion. Focal cerebral ischemia reduced LCGU in the entire ipsilateral cortex, the greatest reduction being in the lateral parts of the frontoparietal cortex. LCGU was slightly reduced in the contralateral cortex; this reduction was considered to be caused by diaschisis. Oxiracetam was administered intraperitoneally for 3 days prior to middle cerebral artery occlusion. In the ipsilateral cortex, LCGU reduction was minimized in the ischemic center areas by oxiracetam at a dose of 400 mg/kg and in more extensive areas, by a dose of 800 mg/kg. Moreover, oxiracetam at a dose of 800 mg/kg enhanced metabolism impaired by diaschisis in the caudal areas of the contralateral cortex. These findings suggest that oxiracetam minimizes the reduction of brain function induced by ischemia and may therefore be useful in the treatment of cerebrovascular disease.

Animals↗
PubMed1992

Lipoma involving the skull. Case report.

The case of an intraosseous lipoma involving the left frontal bone is reported. Lipomas of the bone are rare; only three cases of lipomas involving the skull have previously been reported. The differential diagnosis includes a healing bone infarction or fracture, meningioma, hemangioma, and fibrous dysplasia. Diagnosis prior to surgery is difficult.

Adult↗
PubMed1992

[A ruptured aneurysm at the peripheral collateral circulation of the anterior choroidal artery in a patient with moyamoya disease: a case report].

This 42-year-old man experienced a sudden onset of occipital headache. Neurological examination revealed a moderately disturbed consciousness and a moderate left hemiparesis. CT scan disclosed a hugh hematoma in the right temporo parietal lobe without intraventricular hemorrhage. A cerebral angiography demonstrated typical findings of moyamoya disease and a small saccular aneurysm at the peripheral portion of the right anterior choroidal artery, which was dilated at the collateral circulation to the parietal lobe. The hematoma was removed at once by a craniotomy. He became alert but mild hemiparesis persisted. MRI disclosed a small signal-void lesion lateral to the trigone of the right lateral ventricle. The angiography repeated three weeks after the removal of the hematoma showed the unchanged size of the aneurysm. Direct surgery for the aneurysm was performed via the right parietal transcortical approach. The aneurysm was reached under the guidance of the intraoperative angiography. Trapping of the parent artery and the excision of the aneurysm were performed. On the basis of the presence of an internal elastic lamina at the neck of the aneurysm, the surgical specimen was histologically verified to be a true aneurysm. Since the collateral circulation was well preserved during surgery, no worsening of the neurological manifestation was observed. In view of the unfavorable prognosis for a moyamoya patient with this type of the aneurysm, which often results in a massive ventricular or intracerebral hemorrhage, surgery directed to the aneurysm itself should be considered.

Adult↗
PubMed1992

[Kainic acid-induced generalized seizures in cats--microinjection into caudate nucleus].

Electroencephalographic and behavioral changes were observed after 2 micrograms of kainic acid (KA) injection through a chronically implanted cannula into unilateral caudate nucleus (CN) of freely moving and non-anesthetized cats. The control group showed no changes on EEG or behavior during the observation period. In KA group, from 2 to 5 minutes after KA injection, the cats showed contralateral circling. On EEG, focal spikes were elicited at the injected site of the right CN. From 15 to 25 minutes after the injection, secondarily generalized seizures were observed on EEG repeatedly. However, the behavioral change was not remarkable and only the behavioral arrest was observed during the electrographic generalized seizure. From 6 to 8 hours after injection, they showed clonic seizure of the contralateral hindlimb followed by generalized tonic-clonic convulsion. These seizures were frequent during 6 to 16 hours after injection. However, these seizures subsided within 48 hours after the injection and the cats became normal afterward. Histopathological examination revealed focal pyknosis and gliosis only at the injection site of caudate nucleus. The results suggested that an epileptogenic focus of the caudate nucleus demonstrated a rapid evolution from the focal seizure status to the secondarily generalized seizure status. This fact explains that the caudate nucleus may be a possible key structure as a relay nucleus for the secondary generalization of a focal seizure.

Animals↗
PubMed1992

[Unilateral agenesis of the internal carotid artery in a patient with ruptured aneurysm of the anterior communicating artery; a case report].

This 27-year-old female suffered from subarachnoid hemorrhage. Angiography revealed a ruptured aneurysm of the anterior communicating artery. Unilateral absence of the right internal carotid artery was also demonstrated angiographically. Both the right anterior and middle cerebral arteries were perfused from the left carotid artery via the anterior communicating artery. Absence of the right carotid canal was proved on bone CT. Neuroradiological difficulties in differential diagnosis between agenesis and aplasia of the internal carotid artery were discussed. Subsequently, a diagnosis of adult type unilateral agenesis of the internal carotid artery with collateral circulation was made. The mechanism of association of cerebral aneurysm in patients with agenesis of the internal carotid artery was also discussed. From our experience, abnormal vascular anatomy should be carefully studied prior to direct surgery for a ruptured aneurysm in patients with unilateral agenesis of the internal carotid artery.

Adult↗
PubMed1992

[A case of primary intracerebral malignant lymphoma in systemic lupus erythematosus].

The patient, a 44-year-old female, was admitted to our department because of right hemiparesis and left oculomotor nerve palsy on February 7, 1986. Neither lymphadenopathy nor hepatosplenomegaly was present. She had been treated with prednisolone for systemic lupus erythematosus (SLE) for one and a half year before admission. The CT scan revealed a homogeneously enhanced mass lesion from the midbrain through the thalamus on the right side. The whole body gallium scintigram showed no abnormal uptake except in the brain. Stereotaxic biopsy was performed. Histopathological diagnosis was malignant lymphoma, diffuse, large cell type (International Working Formulation). The enhanced mass lesion disappeared after radiation therapy. Subsequently, she received chemotherapy. She remained well until May 1988 when she died because of the systemic lymphadenopathy. The association of malignant lymphoma and SLE has appeared occasionally in the literature. Primary intracerebral malignant lymphoma associated with SLE is much rarer but it should be considered in the differential diagnosis of symptoms of the central nervous system in a patient with SLE. Therefore, biopsy of a cerebral mass lesion is mandatory if appropriate therapy such as radiation and chemotherapy is to be administered.

Adult↗
PubMed1992

[Effect of anticonvulsants upon experimental limbic seizure status and regional cerebral blood flow in the hippocampus].

Continuous monitoring of regional cerebral blood flow (rCBF) of the hippocampus was made during limbic seizure status in cats by means of a heat clearance method with a calibration method by an electrolytic hydrogen clearance method. A stereotaxic operation was made under Nembutal anesthesia. Local anesthetics were applied to the painful area. Femoral artery and vein were cannulated and served for arterial blood pressure monitoring and drug injection, respectively. Tracheostomy was made and ventilated artificially. A double cannula was inserted to the amygdala and fixed to the skull with a dental cement. Electrodes for heat clearance method, electrolytic hydrogen clearance method and EEG recording were inserted to the dorsal hippocampus. Limbic seizure status was induced by kainic acid microinjection (2 ug) into amygdala via implanted cannula. Baseline rCBF was measured in each cats. Continuous monitoring of rCBF was made before and after intravenous administration of anticonvulsants such as zonisamide (ZNS), valproic acid (VPA), diazepam (DZP), phenobarbital (PB) and phenitoin (PHT). Physiological saline (PHS) was injected for controls. Injection of DZP resulted in strong seizure suppression with decrease of arterial blood pressure and hippocampal rCBF. Intravenous PB demonstrated analogous action with DZP with a mild anticonvulsant effect. Intravenous ZNS or VPA resulted in inhibition of seizure propagation from limbic system to cortex. However, these drugs augmented rCBF of the hippocampus more than 2 hours after administration. PHT and PHS demonstrated no anticonvulsant effect nor rCBF change in the present study.

Animals↗
PubMed1992

[A case of extracerebral cavernous hemangioma in the middle fossa].

Authors reported an autopsy case of extracerebral cavernous hemangioma in the middle fossa and discussed the effect of irradiation therapy on it. A 72-year-old woman was admitted due to progressive deterioration of consciousness and the right hemiparesis. CT scan revealed a slightly high density mass, which was markedly heterogeneously enhanced with contrast media, in the left middle cranial fossa. Angiogram with prolonged injection demonstrated a faint tumor stain. Craniectomy and partial temporal lobectomy for decompression were performed, but the tumor could not be removed due to uncontrollable hemorrhage. Her level of consciousness further deteriorated, and in addition heart failure developed. And finally she became vegetative in spite of effective irradiation therapy of 46Gy. CT scan taken three months and seven years after the irradiation showed marked regression of the tumor. After the vegetative state for 8 years, the patient died of acute pancreatitis, and autopsy was performed. The cavernous hemangioma with markedly proliferated interstitial connective tissue and thrombosed vessels was verified by microscopical examination. Although the treatment was not successful in this patient, we confirmed that irradiation is useful in the management of the extra-axial cavernous hemangioma in the middle fossa as a pre- or postoperative adjunct therapy.

Aged↗
PubMed1992

[A septated syringomyelia with a dramatic clinical course in a young patient with MELAS; a case report].

This is a report of a young girl who showed a recurrence of acute worsening and remission of neurological manifestations, with consistent MRI demonstration of transaxial septated syrinxes in the cervical and the lumbar spinal cord in addition to a tight filum terminale. This 8 year-old girl had developed normally since her birth until August 1989 when she developed a gait disturbance. This worsened acutely on January 1, 1990, with the additional manifestation of a urinary bladder disturbance. General examination failed to show any abnormality or scoliosis. Neurologic examination revealed a monoparesis of the right lower extremity with muscle atrophy and pyramidal tract sign. Fecal constipation and urinary retention were noted. The MRI T1 weighted sagittal image demonstrated an incontinuous low intensity signal in the C1-C7 as well as in the T12-L2 without swelling of the cord. The axial image clearly demonstrated the septations in the syrinx which looked like eye glasses. No definite Gd enhancement was demonstrated. Chiari malformation was not associated, but the tethered cord was well identified. With the administration of steroid, she showed a marked improvement of neurological manifestations. She was able to urinate without difficulty and also walk by herself. For one month thereafter she remained well with minor neurological deficits until she developed a worsening of the gait disturbance with a newly manifested weakness of the left upper extremity. Sensory impairment was also demonstrated below L3. In contrast to the worsening of the clinical symptoms, no definite change in the abnormalities found by MRI was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Lactic↗
PubMed1991

HA1077, a novel calcium antagonistic antivasospasm drug, increases both cerebral blood flow and glucose metabolism in conscious rats.

The effects of a novel calcium antagonistic antivasospasm drug, HA1077, on local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were studied in 33 anatomically discrete regions of the brain in conscious rats, using the quantitative autoradiographic [14C]iodoantipyrine and [14C]2-deoxyglucose techniques. HA1077 was infused i.v. over a 30-min period (1 or 3 mg/kg). HA1077 significantly increased LCBF in 9 of 33 sites in rats given 1 mg/kg, and in 14 of 33 sites in rats given 3 mg/kg compared to the control group given vehicle. Significant increases in LCGU were also noted in 16 of 33 sites in rats given 3 mg/kg. HA1077 increased both cerebral blood flow and glucose metabolism in conscious rats.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Various hippocampal lesions induced by multi-fractional ibotenic acid injections and amygdala kindling in rats.

Hippocampal degenerative lesions were made bilaterally by means of multiple ibotenic acid injections and development of amygdala kindling was studied. In groups with lesions in either bilateral dorsal or ventral hippocampus, stimulations required for kindling were almost the same as those of controls. In the group with lesion of the entire hippocampus, kindling development was remarkably slow especially in the early stage of the kindling process. However, kindling effect was finally established in all groups.

Amygdala↗
PubMed1991

Effects of induced hypertension on blood flow and capillary permeability in rats with experimental brain tumors.

To study the possibility of enhancing the delivery of antineoplastic agents to tumor tissue, we conducted an experimental study using induced hypertension with angiotensin II in rats with experimental brain tumors. Drug delivery was evaluated by measuring local cerebral blood flow (LCBF) and regional cerebral capillary permeability with quantitative autoradiography. There was no significant difference of LCBF in the central region of tumor tissue between the control group and the induced hypertension group. LCBF in the peripheral region of tumor tissue in the induced hypertension group was significantly higher than that in the control group. On the other hand, despite induced hypertension, no significant changes in the regional cerebral capillary permeability were observed between the groups. These results indicate that delivery of the lipid-soluble antineoplastic agents, which depend upon cerebral blood flow, can be enhanced by induced hypertension.

Aminoisobutyric Acids↗