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Biomedical subjects

Y Yonemasu

Publications and source records attributed to Y Yonemasu.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1991

Secondary generalization in kainic acid-induced focal seizures in unanesthetized cats.

Seizure propagation was studied with different seizure models induced by a kainic acid (KA) microinjection in nonanesthetized cats. These seizures were characterized with a focal onset of seizures followed by secondarily generalized seizures. The mesencephalic reticular formation (MRF) played an important role when an epileptogenic focus was located in a unilateral amygdala, hippocampus, thalamus or visual cortex. When the focus was located in a unilateral lateral geniculate body, a fast, synchronous and bidirectional propagation was observed in the sensorimotor cortex (SMC) and MRF. Brain stem seizure (generalized tonic seizure) was elicited by the KA injection into MRF. The EEG of generalized seizure was characterized by the propagations of seizure activities of MRF immediately to the bilateral SMC and thalamus. The results suggested that MRF participated actively in the generalization of the KA-induced seizures.

Animals↗
PubMed1991

Relationship between 22Na distribution and cerebral blood flow in ischemic gerbil brain.

Sodium transport in the early postischemic period was studied using Mongolian gerbils with right common carotid artery ligation. [22Na]sodium chloride ([22Na]NaCl) was infused immediately after, 10 minutes before, and 4 hours before carotid ligation, and the 22Na distribution was measured in symptomatic animals by autoradiography 1 hour after ischemia. Regional cerebral blood flow was determined by [14C]iodoantipyrine autoradiography. The specific gravity of the brain was measured in symptomatic gerbils 1 and 2 hours after carotid ligation by a gradient column. There was a low uptake of 22Na in the ischemic core and a high uptake in the ischemic periphery when the tracer was given 10 minutes before or immediately after ischemia. In contrast, tracer given 4 hours before ischemia showed an increased radioactivity in both the ischemic core and periphery. It is suggested that increased sodium in the ischemic core is due to a decreased sodium clearance rate and increased sodium in the ischemic periphery is due to some active transport process.

Animals↗
PubMed1991

The role of the paraventricular nucleus and pituitary gland in morphine analgesia.

The authors investigated the analgesic effects of small morphine doses injected into the paraventricular nucleus (PVN) of normal rats and hypophysectomized (Hx) rats. An injection cannula was stereotactically inserted into the PVN or third ventricle. On the 5-7th postoperative day, morphine (7 micrograms) was injected and the pain threshold (paw lick latency: PLL) was measured using a hot plate analgesia meter (52.0 +/- 0.1 degrees C). PVN morphine injection caused significantly longer PLL than the control (physiological saline) in both normal and Hx rats. Ventricular morphine injection did not increase PLL over the control. PVN is a site of morphine action. The analgesia induced by PVN morphine injection was not affected by hypophysectomy, or induced by leaking of morphine into the third ventricle.

Analgesia↗
PubMed1991

[Spontaneous disappearance of aneurysm after total removal of accompanying intracranial arteriovenous malformation. Case report].

A 55-year-old male was hospitalized with severe headache. On admission, neurological examination revealed no abnormal findings. Plain computed tomography (CT) showed a slightly high-density area in the medial surface of the right parietal lobe. A marked enhancement in the same region was noted in enhanced CT. Cerebral angiography showed an arteriovenous malformation (AVM) in the medial surface of the right parietal lobe and two aneurysms on the right pericallosal artery which fed the AVM. In addition, a saccular aneurysm was noted at the anterior communicating artery. It was not possible to treat the AVM, two aneurysms nearby the AVM, and the unruptured anterior communicating artery aneurysm simultaneously with a single craniotomy. It was therefore decided to perform surgery for the AVM and two aneurysms nearby the AVM prior to clipping of the anterior communicating artery aneurysm. Total excision of the AVM and two aneurysms nearby the AVM was performed. Cerebral angiography performed 18 days after surgery revealed no AVM and also reduction in size was noted of the anterior communicating artery aneurysm. Three months later, repeated cerebral angiography showed disappearance of the aneurysm. This was further confirmed 15 months after surgery by angiography. From the literature, 117 cases of coexistence of AVM and aneurysms of the brain were collected and classified into three types according to their anatomical and hemodynamic correlation. It is suggested that hemodynamic stress, due to increased blood flow caused by the AVM, played a major role in the development of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamics↗
PubMed1991

[A case of multiple myeloma (biclonal type) associated with an intracranial mass invading the skull base and oculomotor palsy].

A case of multiple myeloma forming an intracranial mass which invaded the skull base was reported. A 72-year-old woman was admitted to the hospital because of left oculomotor paresis. Plain craniograms showed multiple punched out lesions. A CT scan demonstrated a mass lesion, which was homogeneously slightly enhanced with contrast medium, in the middle cranial fossa. MRI, both T1 and T2 weighted images, showed an isodensity mass. In the carotid angiograms the tumor was fed by the right branches of the cavernous portion of the internal carotid artery and the maxillary artery. Laboratory data were as follows: ESR: 132mm/30min, serum TP: 9.0g/dl, IgG: 4670mg/dl, IgA: 430mg/dl, and urinary Bence-Jones protein was detected. Bone marrow biopsy of the illiac bone demonstrated myeloma cells. During hospitalization oculomotor paresis disappeared, and the patient was treated with intramuscular interferon-alpha. Multiple myeloma which invades the skull base is rare, and only 10 cases have been reported since 1977. Moreover, the biclonal type is only 0.5% of all multiple myelomas.

Aged↗
PubMed1990

Uncoupling of local blood flow and metabolism in the hippocampal CA3 in kainic acid-induced limbic seizure status.

Limbic seizure status was induced by microinjection of kainic acid into a unilateral amygdala in rats. Two hours after kainic acid injection, distant neuronal cell damage was produced, especially in the hippocampal CA3 on the kainic acid-injected side. In order to elucidate the mechanism of this neuronal cell damage, local cerebral glucose utilization and local cerebral blood flow were studied by means of an autoradiographic method using [14C]2-deoxyglucose and [14C]iodoantipyrine during kainic acid-induced limbic seizure status. These studies were performed 2 h after kainic acid microinjection into a unilateral amygdala. Both local cerebral glucose utilization and local cerebral blood flow were remarkably increased in the limbic system, ventrobasal complex of the thalamus, septal nucleus, nucleus accumbens, caudate nucleus, substantia nigra and hypothalamus on the kainic acid-injected side. In the hippocampus, local cerebral glucose utilization increased 2.6 times control in CA1 and 4.1 times in CA3, whereas the rates of increase in local cerebral blood flow were similarly low in CA1 and CA3: 1.2 and 1.4 times control, respectively. The results demonstrated that the degree of uncoupling of local cerebral glucose utilization and local cerebral blood flow were higher in CA3 than in CA1, and also suggested that relative hypoxia occurred in CA3 in this high degree of uncoupling, resulting in pyramidal cell damage in CA3 in kainic acid-induced limbic seizure status.

Animals↗
PubMed1990

Measurement of cerebral blood flow, cerebral blood volume, and cerebral capillary permeability in glioma-bearing rats.

Effective chemotherapy and radiation therapy of brain tumors require knowledge of the cerebral circulatory dynamics involved. In this study, regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), and regional cerebral capillary permeability (rCP) were measured in Wistar King Aptekman rats bearing experimental KEG-1 gliomas. These parameters were assessed by autoradiography with 14C-iodoantipyrine, 14C-deoxyglucose-labeled red blood cells, and 14C-aminoisobutyric acid, respectively. rCBF within the tumor was approximately one third that in the contralateral cortex and was consistently higher in the periphery than in the center of the tumor. In the periphery of the tumor, rCBV was approximately twice that in the contralateral cortex, but it was very low in the center of the tumor. Throughout the tumor, rCP was sharply increased relative to that measured in the contralateral cortex, and the increase was especially pronounced in the central portion. Thus, rCBF, rCBV, and rCP each appeared to vary within the tumor, implying that the combined use of lipid- and water-soluble chemotherapeutic agents is reasonable. Measurement of these parameters may also provide indices of radiation sensitivity.

Animals↗
PubMed1990

Diffuse low-density areas in white matter on CT scans after intracarotid ACNU infusion--report of three cases.

Since 1984, we have treated 11 malignant glioma patients with intracarotid infusion of ACNU [1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)- 3-nitrosourea hydrochloride] in addition to surgical removal and irradiation. We experienced three patients, who showed clinical manifestation of leukoencephalopathy and computed tomographic (CT) findings of diffuse low-density areas in the white matter on the side of ACNU infusion. Two of the three patients showed an additional CT finding of ring enhancement in the temporo-occipital region. The histological diagnosis of the first case was radiation necrosis, while that of the others was recurrent tumor with coagulation necrosis in the surrounding brain. Our experience suggests that intracarotid ACNU infusion increases the hazard of radiation necrosis, and the optimum dose and effective mode of administration should be evaluated.

Brain↗