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Biomedical subjects

T Ohira

Publications and source records attributed to T Ohira.

136 records · Page 8Linked to original sources
PubMed1985

[A case of concomitant posterior fossa and supratentorial hemangioblastomas].

The patient was a 31-year-old female who complained of headache and gait disturbance and admitted to our hospital on January 14, 1983. Familiar history revealed that her mother died of hemorrhage from hemangioblastoma in area postrema. Neurological examination revealed bilateral papilledema, right cerebellar sign and ataxia. Other neurological and clinical examinations were normal. CT-scan showed a right cystic cerebellar lesion and a right intraventricular lesion suggestive of hemangioblastomas. Right vertebral angiography demonstrated two vascular tumors lying in the right cerebellar hemisphere and right trigone of the lateral ventricle. Operation was performed on January 28, 1983. The histological diagnosis were hemangioblastomas.

Adult↗
PubMed1984

Effects of intraarticular injection of halopredone diacetate on the articular cartilage of rabbit knees: a comparison with methylprednisolone acetate.

Halopredone diacetate, which is a new synthetic corticosteroid drug showing local retention, and methylprednisolone acetate in common clinical use were injected into the knee joints of adult rabbits to compare the effects of the two drugs on the articular cartilage. The dosage of one injection was 1.75 mg (H-1 group) and 8.75 mg (H-5 group) for halopredone diacetate and 1.4 mg (M-1 group) and 7.0 mg (M-5 group) for methylprednisolone acetate. The drugs were injected into the right knee joint once a week, 12 times in total. One week after the last injection, the steroid crystals remaining in the knee joint were observed in all rabbits in the H-1 and H-5 groups. White deposits were seen locally on a part of the cartilage in all the rabbits in the H-1, H-5, and M-5 groups but not in the M-1 group. These white deposits were observed as cystic lesions by light microscopy and contained abundant hydroxyapatite. Other histologic findings in the articular cartilage included fissure, hypocellularity, and a decrease of proteoglycan in each group. However, no distinct difference was noted between the H-1 group and the M-1 group as regards the histological-histochemical grades of the cartilage on the medial tibial condyle or in the electron microscopic findings of the cartilage on the medial femoral condyle. The same was true for the H-5 and M-5 groups. These results show that repeated intraarticular injections of these two drugs cause severe cartilage lesions to the same degree, except for the intracartilaginous white deposits of rabbit knees.

Animals↗
PubMed1984

[Transcortical sensory aphasia produced by lesions of the anterior basal ganglia area].

We reported three cases of an aphasic syndrome caused by unusual lesion distribution. Our patients, language disorders could be summarized as transcortical sensory aphasia and showed following symptoms; (1) fluent paraphasic verbal output, (2) anomia which was not facilitated by cueing, (3) impaired comprehension of spoken language, (4) preserved capacity of repetition, (5) preserved ability of reading aloud with impaired comprehension of the written material and (6) agraphia. In addition, all had no associated physical neurological signs such as hemiparesis or hemianopsia. All were right handed. All three cases showed the similar lesion distribution by computed tomographic scanning of the brain. All had low density areas in the anterior portion of the left basal ganglia including the head of the caudate nucleus, the anterior portion of the putamen, the anterior portion of the anterior limb of the internal capsule and the nearby white matter. Case 2 also had the small right hemisphere lesion in the white matter near the anterior portion of the lateral ventricle. Transcortical sensory aphasia with this lesion distribution has not been reported. We attributed the causative damage to lesions of the white matter and not to lesions of the basal ganglia per se. It was also speculated that fluent aphasia can be produced by the anteriorly situated white matter lesion if issuing fibers from the Broca's area were spared. Finally a possible anatomoclinical correlation for "transcortical alexia" (preserved oral reading and impaired reading comprehension) was attempted. The symptom is probably a reflection of the fact that the posterior speech area including the angular gyrus was left intact.

Aged↗
PubMedDate not supplied

Three-dimensional human somatosensory evoked potentials.

Median nerve somatosensory evoked potentials were recorded from 30 normal adults using conventional scalp derivations and an orthogonal bipolar surface electrode montage. This allowed the determination of the spatial orientation of the hypothetical centrally located equivalent dipole derived from the evoked response recorded in 3-dimensional voltage space. The 3-dimensional voltage trajectory describing changes in equivalent dipole orientation and magnitude revealed 4 major apices between 5 and 25 msec, 3 of which corresponded to the traditional P14, N20 and P25 peaks. A fourth apex at 17 msec was not as evident in the conventional recordings and signaled a transition from a vertical P14-N18 generator process to a horizontal N20 generator process. The normal within- and between-subject variability of trajectory apices, segments and planes are described, along with the theoretical and practical implications of this recording technique.

Adult↗
PubMedDate not supplied

Three-dimensional human pattern visual evoked potentials. I. Normal subjects.

Pattern visual evoked potentials (PVEPs) were obtained from 30 normal adult volunteers, recording from both a conventional horizontal occipital array and three orthogonal bipolar antipodal channels approximating the three dimensions of space. Central and eccentric fixation of 60' checks and central fixation of 30' checks under binocular and monocular viewing conditions was employed. The three antipodal wave forms were displayed as a single 3-D Lissajous trajectory which contained four apices, corresponding to P40 (apex A), N70 (apex B), P100 (apex C) and N125 (apex D). The 3-D evoked potentials depicted the dynamic nature of the human PVEP in terms of changes in the 3-D voltage-voltage-voltage plots of the recordings. The orientation of the A-B, B-C and C-D curvilinear segments reflected the stimulating condition (central fixation vs. right vs. left hemi-field stimulation) for all subjects with more accuracy than did the wave forms from the conventional array. Spherical statistical methods are described for quantifying and evaluating 3-D evoked potential recordings.

Adult↗
PubMedDate not supplied

Suramin inhibits the phosphorylation and catalytic activity of DNA topoisomerase II in human lung cancer cells.

Suramin is a prototype of a new class of anticancer drugs. We investigated the action of suramin on the signal transduction pathways to DNA topoisomerase II (Topo II). Suramin showed a growth-inhibitory effect on a human lung cancer cell line (PC-9) with an IC50 of about 160 micrograms/ml. Suramin inhibited the catalytic activity of Topo II with an IC50 of about 100 micrograms/ml without stabilization of the cleavable complex of DNA and Topo II. Suramin decreased the phosphorylation of Topo II with an IC50 of 175 micrograms/ml, but did not change the degree of Topo II expression. These IC50 values for inhibition of catalytic activity and phosphorylation of Topo II were equivalent to the growth-inhibitory dose determined by tetrazolium dye assay. Phosphorylation of the tyrosine residues of Topo II was not changed by suramin. In the presence of okadaic acid, a potent inhibitor of serine/threonine protein phosphatase, suramin also decreased the phosphorylation of Topo II, suggesting that the drug did not act on the serine/threonine protein phosphatases inhibited by okadaic acid. Suramin also inhibited the protein kinase C (PKC) activity of PC-9 cells. These results suggest that suramin decreases the phosphorylation of Topo II mediated by PKC. This effect of suramin might cause the inhibition of Topo II activity resulting in the growth inhibition of tumor cells.

Blotting, Western↗