PubMed Health⌕ Search

Biomedical subjects

J Okamoto

Publications and source records attributed to J Okamoto.

At least 55 records · Page 3Linked to original sources
PubMed1984

Field mapping of EEG by unbiased polynomial interpolation.

The technique for field mapping of EEG using interpolation by an unbiased estimator of two-dimensional isotropic higher-order polynomial is developed. Assuming that the observed EEG contains noise, this method permits free positioning of the electrodes and does not reveal artificial oscillations as large as those of the Gibbs' phenomenon as in the case of the widely used Fourier interpolation. In the example of RMS (root mean square) amplitude at anesthesia, the onset of the fast activities began to appear clearly in the frontal and occipital area. By this method, not only RMS amplitude, but also instantaneous amplitude, such as visual evoked potential and somatosensory evoked potential, can be mapped.

Anesthesia↗
PubMed1984

[Destruction of apical dendritic layers in penicillin-induced cortical epileptic focus].

It has been generally accepted that topectomy is a choice of treatment for patients who have an intractable cortical epileptic focus. However, the surgery is not indicated in the cases whose focus is functionally involved in the vital cortical regions. We have experienced a case of intractable traumatic cortical epilepsy, in which the patient underwent cortical surface coagulation on his motor cortex during the dissection of his wide-spread durocortical adhesion. Subsequently, his epileptic attacks have been abolished completely for over 7 years without motor deficit. It is the purpose of this work to confirm experimentally that destruction of apical dendrites on the epileptic focus may prevent occurrence of abnormal spike epileptic discharges without vital neuronal deficit. Fifty dogs were used in this study. In normal dogs, the antidromic cortical response, after stimulation of the internal capsule, showed three predominant negative waves axonal (the first), cortical neuronal (the second) and apical dendritic potentials (the third) by surface recordings. Upon creation of the penicillin-induced cortical epileptic focus, spike discharges appeared on the corticogram, and the third wave of the antidromic cortical response shifted from negative to positive. Selected destruction of the dendrites, in the first and the second cortical layers, in the area of the epileptic focus brought about disappearance of the third wave, to isopotentially, and a marked inhibition or complete disappearance of spikes on the corticograms. The possibility exists, as been suggested by our experiment, to clinically apply this method as a treatment for intractable cortical epilepsy with foci in the functionally vital regions, although there are yet many problems to be solved.

Animals↗
PubMed1983

[Cerebellar cyst associated with cytoarchitectonic abnormalities in the cerebellar cortex].

The patient, 64-year-old female, had episode of sudden attack of severe vertigo, headache, nausea, and vomiting which lasted for about twenty minutes on May 20th in 1980. She had hypertension, polyp of stomach, diverticuli of duodenum in her past history. Neurological examination on her admission revealed fine horizontal nystagmus on bilateral gaze and slight clumsy movement on left F-N test. On plain skull and cervical X-P, atlanto-occipital fusion and Klippel-Feil syndrome (C2-C3 fusion) were seen. Plain CT scanning revealed a large cystic lesion which extended from the vermis to the left cerebellar hemisphere. No enhanced area was seen. The forth ventricle was seemed to be enlarged. And the left-sided dorsal part of the forth ventricle attached to the cyst. Metrizamide CT cisternogram showed there was no direct communication between them. Angiographically, the vertebrobasilar arteries were noted sclerotic changes and poor vascularities in the left cerebellar hemisphere was noted. On opening the dura during surgery, the left cerebellar hemisphere appeared bulging state and the bilateral cerebellar tonsils were hypoplastic. Outer thin membrane of the cyst was removed. The cyst has no communication with the subarachnoid space as well as with the forth ventricle. The cystic fluid was slightly yellowish, but had no Froin's sign. Reddish-gray color nodular area, which seemed to be similar to mural nodule macroscopically, was noted in the area of inner surface of the cyst. This part was removed. Histological findings of this area showed abnormal architecture with malarranged layer of cerebellar cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebellar Cortex↗
PubMed1982

[A case of atypical moyamoya disease with a ruptured aneursym on moyamoya vessel].

A 45-year-old female had sudden onset of severe headache, nausea and vomiting without any inducing moments and was transferred to our hospital by an ambulance car. On admission the patient was alert and showed only signs of meningeal irritation. There were no other neurological deficits at all. Immediate CT examination revealed a small high density spot in the area of the right basal ganglia, and a large high density in the frontal horns of both lateral ventricles. Right carotid angiogram showed completely patent carotid siphon with Moyamoya vessels. A small round aneurysmal shadow of 3 mm in diameter was seen in the area of these Moyamoya vessels of the right basal ganglia, and it was thought to be corresponding to the high density spot in the CT examination. Left carotid angiogram showed stenosis of C portion with typical Moyamoya vessels. Therefore, diagnosis of atypical Moyamoya disease with a ruptured aneurysm and ventricular penetration of hematoma was made. The patient was placed on conservative treatment. On 25th day from onset, repeated angiogram showed enlargement of the aneurysmal shadow from 3 mm to 5 mm in diameter. So, on 33rd day, right STA-MCA anastomosis and encephalomyosynangiosis were carried out. Angiogram on 12th day after surgery revealed no aneurysmal shadow. The patient was discharged without any neurological deficit at all. Previous paper, which reported cases of Moyamoya disease with aneurysm, were reviewed. According to the location of the aneurysm, these cases were classified into 3 types angiographically; type I: aneurysm in the area of Moyamoya vessels, type II: aneurysm of cerebral-peripheral artery, and type III: aneurysm of the circle of Willis. It has been generally believed that the Moyamoya disease may be associated with either a true or a pseudoaneurysm in the case of type I. However, pseudoaneurysm in the area of Moyamoya vessels has not been found in postmortem examination but true aneurysms so far. Therefore it may not be denied that the aneurysm of this case was true aneurysm although it showed an enlarging tendency and disappeared rather spontaneously.

Arterial Occlusive Diseases↗
PubMed1980

Presence of smooth muscle myosin-like protein on liver cells.

Antiserum against purified chicken smooth muscle myosin was obtained from rabbits. The serum was specific for smooth muscle myosin and did not react with myosins from fast and slow skeletal muscle or cardiac muscle. Using this specific antibody, the location of smooth muscle myosin-like protein was studied by double antibody immunofluorescence microscopy with sections of chicken liver tissue. Marked fluorescence was demonstrated along the sinusoids of hepatic tissue and the vascular walls. The findings in this study suggest that a myosin-like protein, which is immunologically similar to the myosin from smooth muscle but not to myosins from skeletal or cardiac muscle would exist on the sinusoidal surface of liver cells.

Animals↗
PubMed1977

Immunological specificity and memory in a scleractinian coral.

Tissue transplantation immunity with a specific memory component is demonstrated in populations of Montipora. This highly discriminating immunoreactivity derives from extensive allogeneic polymorphism of histocompatibility (H) markers. An H system of immunorecognition is postulated to have originated in multicellular invertebrates probably beginning with coelenterates.

Animals↗