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Biomedical subjects

T Ohmoto

Publications and source records attributed to T Ohmoto.

At least 289 records · Page 16Linked to original sources
PubMed1983

[Electrical stimulation of the posterior limb of the internal capsule for treatment of thalamic pain].

Electrical stimulation of the posterior limb of the internal capsule was performed in six patients with central pain due to vascular lesions of the thalamus. Three patients suffered from thalamic hemorrhage and the other three from ischemic insult. These patients developed dysesthesia, hyperpathia and spontaneous burning pain several months after cerebral vascular diseases. These severe pain were not relieved by any trials of anticonvulsants, psychopharmacological and analgesic drugs. Stimulating electrode system manufactured by Medtronic, Co. was implanted stereo-taxically in the posterior limb of the internal capsule which was 25 mm lateral to the posterior commissure. Ramped bipolar stimulation with a square pulse 2-3 V, 0.2 msec, 50 Hz elicited sensory response such as warm or comfortable sensation. Satisfactory relief of pain was obtained in most cases by 30-minutes-long stimulation twice or three times a day for various period of time ranging from 10 to 14 days. Long-term follow-up ranging from three months to two years showed that three patients had a good result (incomplete pain relief by stimulator with no medication required), two had a fair (incomplete pain relief by stimulator with decreased doses of medication) and another one had a poor result in which the pain had not been relieved with the stimulation in one month. No remarkable side effects were seen. These results indicate that the internal capsule stimulation is more effective and lasts longer than the various ablative methods to relieve central pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1980

Primary intracranial choriocarcinoma.

The authors report four cases of primary intracranial choriocarcinoma, all in young males. There tumors occurred in the pineal region and one in the lateral ventricle. Besides the signs of increased intracranial pressure and ophthalmological disorders, skin pigmentation or eruption was observed in three cases and precocious puberty in two cases. Angiography revealed tumor stain with irregular vessels in all cases. Enhanced computerized tomography scans in the last two cases demonstrated a round, lobulated lesion of high density, with relatively low density in the central portion. Hormonal study was carried out in three cases. In addition to high levels of human chorionic gonadotropin (HCG) in the urine and cerebrospinal fluid and/or of plasma luteinizing hormone (LH), LH in tumor tissue or medium obtained via cell cultures was also high in all three cases, suggesting inherent activity of HCG secretion by the tumor cells. The tumors were relatively demarcated from the surrounding brain. They were very hemorrhagic, and fresh hematoma was identified in the tumor in case. Good results were obtained in two cases treated with surgical removal followed by simultaneous chemotherapy and 60Co irradiation.

Adolescent↗
PubMed1979

[Histopathological study on experimental cerebral infarction in rat (author's transl)].

An experimental model of cerebral infarction in rat brain was successfully established by means of the unilateral internal carotid injection of carbon microspheres. A histopathological investigation of the infarcted brain was performed. The results were as follow: 1. No cerebral infarction was made by the unilateral internal carotid ligation alone. 2. Focal cerebral edema was most marked at the white matter of the embolized hemisphere. 3. The edema was also conspicuous in the deep cerebral gray matter, especially in hippocampus. Degeneration and pyknosis of the neurons were observed at the same area. 4. Transudative hemorrhage in the focal cerebral edema was usually observed in the thalamus. 5. Edematous change in the cortical gray matter was not so marked as compared with the hippocampus and thalamus. 6. Carbon microsphere was not found in the capillaries of ipsilateral choroid plexus. The present experimental model of cerebral infarction will be useful in elucidating the pathological mechanisms of the cerebral infarction.

Animals↗
PubMed1978

Thalamic control of spontaneous alpha-rhythm and evoked responses.

EEG, depth recordings from the thalamus, visual-evoked potentials, and readiness motor potentials were analyzed with a computer in 40 patients with involuntary movements and intractable pain who underwent stereotactic thalamotomy. It was demonstrated that there were significant correlations in alpha-rhythms between the ventrolateral (VL) nucleus and the frontocentral cortex, and also between the centromedian nucleus and the centroparietal cortex, with the phase difference of the cortex lagging behind the thalamus. Relationships between the thalamic VL nucleus and the frontocentral cortex were significant not only in alpha-rhythms, but also in evoked responses following photic stimulations, voluntary movements, and electrical thalamic stimulation. Thalamotomy produced a bilaterally decreased synchronization of the cortical alpha-rhythms, which recovered within 6 months.

Alpha Rhythm↗