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Y Yonemasu

Publications and source records attributed to Y Yonemasu.

At least 127 records · Page 7Linked to original sources
PubMed1983

[Rapid hippocampal kindling following intraamygdaloid injection of quisqualic acid in cats].

Quisqualic acid (QA) is a potent neuroexcitant and a heterocyclic analogue of glutamate as is kainic acid. Twenty micrograms of QA in unilateral lateral amygdaloid nucleus of cats produced a transient limbic status epilepticus lasting 20-30 hours. Over 14 days after recovery from the limbic status, the animals received daily electrical stimulation to the ipsilateral hippocampus at the intensity of afterdischarge threshold which was determined before the injection of QA. These stimulations resulted in secondarily generalized convulsive seizures in all animals within 4 to 12 days. Spontaneous secondarily generalized seizures were confirmed in two cats after completion of the hippocampal kindling. This rapid completion of the kindling process is interesting phenomenon in contrast to the report that the hippocampal kindling took nearly 60 days. This rapid completion of the kindling effect is considered to be due to the transfer effect (Goddard, 1975) established in the ipsilateral hippocampus by severe bombardments from the amygdala stimulated by the injection of QA as the primary focus. In addition, the pathological changes in the amygdala and hippocampus on the injected side might be related to the rapid kindling process of the ipsilateral hippocampus as the irritable foci.

Amygdala↗
PubMed1982

Electroclinical features of kainic acid-induced status epilepticus in freely moving cats. Microinjection into the dorsal hippocampus.

Electrographic and clinical observations were made after the injection of kainic acid into the unilateral hippocampus of freely moving cats. Vehicle solution (phosphate buffer solution) for control study and kainic acid(1, 4 and 12 micrograms) were administered via a chronically implanted cannula. The control group showed no modification during the observation period. After the injection of 1 microgram of kainic acid, focal status epilepticus was observed for 2-3 days and then cats became normal afterwards. In the group of 4 micrograms kainic acid infection, cats demonstrated limbic status for 3 days, and persistent inter-ictal discharges continued during the observation period. Independent amygdaloid seizures and secondary generalized convulsions developed in the cats administered 12 micrograms of kainic acid. The cats died in the status epilepticus. The dose-dependent and substantial effect of KA without the influences of anesthesia and surgery was demonstrated. The results were discussed in relation to the human medial temporal sclerosis and the effects on the emotional mechanism of the limbic system. We suggest this model to be useful in the study of various types of temporal lobe epilepsy and the emotional mechanisms of the limbic system.

Amygdala↗
PubMed1980

A genetic aspect of chromatin proteins of human brain tumors.

Electrophoretic analysis of chromatin proteins was performed on rat and human tissues. Species and organ specific patterns were demonstrated in them. Twenty cases of human brain tumours were also analyzed and each tumor had typical phoretic patterns of chromatin. Proteins obtained from histologically similar tumors display similar electrophoretic patterns. As to the ratio of chromatin protein to DNA, no apparent differences between benign and malignant human brain tumors were observed.

Animals↗
PubMed1978

[The smear method for histological diagnosis of the tumors of the central nervous system (author's transl)].

The smear method for rapid diagnosis of tumors of the central nervous system at operation is not popular in this country, although this has been widely used in North America and Europe since 1930s. During the period from 1958 to 1976 we experienced 1447 histologically verified tumors of the central nervous system. This smear preparation stained by eosin and methylene blue was made for rapid diagnosis in 718 cases of them. We reviewed these cases and described microscopical findings of various kinds of tumors. In over 90% of cases the correct diagnosis will be obtained from the smears. It can be said that the smear method is appropriate for intraoperative rapid diagnosis of neurosurgical cases.

Adenoma↗
PubMedDate not supplied

Regional cerebral blood flow and kainic acid-induced focal limbic seizures in cats.

An experimental limbic seizure was induced in cats by microinjection of kainic acid into the left amygdala. Measurement of regional cerebral blood flow (rCBF) in the limbic structure and cerebral cortex was performed by means of the hydrogen clearance method. Immediately after the development of continuous multiple spikes, rCBF increased about 2-fold in the left amygdala (LA) and remained so during the seizure. When continuous multiple spikes were transmitted to the left hippocampus (LH), rCBF in the LH increased to 140% of the baseline value, but in the right amygdala (RA) and left sensorimotor cortex (LCx) it remained unchanged. During limbic seizure in which spike discharges propagated to the LCx, rCBF in the LA, RA, LCx and LH increased to 220%, 130%, 120% and 190%, respectively. In the interictal stage in which interictal spike discharges intermittently appeared in the LA, rCBF returned to baseline values in the primary and secondary foci. The results show that rCBF increased almost simultaneously with the development of the seizure in the primary focus and the areas where seizure propagation were observed, and returned to baseline value once the seizure had disappeared. During the interictal stage, rCBF in the primary focus was only slightly increased in spite of persistence of interictal spike discharges.

Amygdala↗