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Biomedical subjects

Y Murai

Publications and source records attributed to Y Murai.

At least 163 records · Page 9Linked to original sources
PubMed1988

Serum erythropoietin titers in the aged.

Erythropoietin (Epo) titers in the aged (from 70 to 89 years) were determined by a radioimmunoassay. Epo levels in normal elderly subjects were not different from levels in the young volunteers. The serum Epo levels in elderly patients with anemia were inversely related to hemoglobin levels; their regression coefficient was not worse than that found in young patients. It is suggested that the reactivity of Epo production to anemia in the aged may not be worse than that reactivity in the young.

Aged↗
PubMed1987

Variability of initial cortical sensory evoked potentials to posterior tibial nerve stimulation.

Scalp topographies and distributions of initial cortical positive-negative components of somatosensory evoked potentials (SEPs) to posterior tibial nerve stimulation were studied in 12 normal controls in order to investigate the generator sources of the cortical SEPs. There are three variations in topographies and distributions of early cortical SEPs in normal subjects. In 5 of 12 cases initial cortical positive-negative components were distributed over the centro-parietal areas ipsilateral to the stimulation site or midline parasagittal areas. The origins of these components are speculated to be vertical dipolar generators located at the contralateral interhemispheric fissure. In 5 of 12 cases P37/N36, and N45/P43 showed a phase reversal between the left and right hemispheres and may be generated from horizontal dipoles located at the contralateral interhemispheric fissure. In 2 of 12 cases N36 and P43 were distributed predominantly over the contralateral hemisphere. Oblique dipolar generators located at the contralateral interhemispheric fissure may be oriented prominently to the contralateral hemisphere. Normal variations of initial cortical positive-negative components of SEPs to posterior tibial nerve stimulation should be considered in their clinical applications.

Adolescent↗
PubMed1987

Neutralizing monoclonal antibodies against recombinant human interleukin-2.

A series of hybridoma cell lines which produce monoclonal antibodies (MAbs) against recombinant human interleukin-2 (rIL-2) have been established by fusion of murine myeloma cell line P3-NS1-1-AG4-1 and spleen cells of BALB/c mice which had been immunized with rIL-2. 48 hybridoma strains were selected by a solid-phase screening method which produced MAbs reacting with IL-2: four MAbs, L-15, L-20, L-34, and L-61, exhibited strong inhibition of the proliferating effect of rIL-2 on IL-2-dependent cell lines, NK7 and CTLL-2. L-61, the most potent MAb among them, also neutralized natural human IL-2, while the other three MAbs were unreactive. All the four MAbs were specific to human IL-2: they did not cross-react with mouse or rat IL-2. These MAbs are expected to be useful tools in the investigation of IL-2 function.

Antibodies, Monoclonal↗
PubMed1987

Primary segmental demyelination in the sural nerve in Cockayne's syndrome.

In a typical case of Cockayne's syndrome, morphometric histopathologic findings of the sural nerve were described and compared with data on two controls. The main pathologic changes of myelinated fibers were segmental demyelination and remyelination with onion bulb formation and a moderate decrease of myelinated fibers. There was no evidence of axonal atrophy in relation to myelin spiral length. In addition, no evidence of the clustered occurrence of demyelinated and remyelinated internodes was obtained on the statistical evaluation of the distribution of such internodes. Although the presence or absence of hypomyelination of a mild degree and maldevelopment of axons to be myelinated has not been clarified, our morphometric data do suggest the presence of primary segmental demyelination of the biopsied sural nerve.

Biopsy↗
PubMed1986

[The effect of clioquinol on nerve fiber regeneration following nerve crush injury].

The effect of clioquinol on regeneration of myelinated fibers of the sural nerve in rats was studied. Clioquinol suspended in polyethylen glycol (300 mg/kg body weight/day, test) and polyethylen glycol only (control) were administered for 14 and 21 days starting 7 days before the nerve crush. The number of regenerating myelinated fibers was examined histologically at 7 and 14 days after the nerve crush. In the control and test groups the regenerating fibers reached between 0-5 mm point from the crushed point at 7 days. The regenerating fibers reached between 15-20 mm point in the control group and between 5-10 mm point in the test group at 14 days. The rate of regeneration of myelinated fibers in test rats was significantly reduced compared with control.

Animals↗
PubMed1986

Frequency of accumulation of filaments in adaxonal cytoplasm of Schwann cells of myelinated fibers of rat spinal roots. Comparison between ventral and dorsal roots and between growing and mature rats.

The frequency of accumulation of 6-nm filaments in the adaxonal cytoplasm of Schwann cells in the 6th lumbar dorsal and ventral roots was evaluated in 4-, 8-, 26- and 45-week-old Sprague-Dawley rats. The frequency was higher in 4- and 8-week-old (growing) rats than in 26- and 45-week-old (mature) rats, and also higher in ventral than in dorsal roots in 4-, 8- and 26-week old rats. There were no clusters on certain groups of myelinated fibers according to the size of transverse axonal area, in both the ventral and dorsal roots. Therefore, this accumulation may reflect certain functions of the adaxonal cytoplasm of Schwann cell during natural growth and maturation of the axon and myelin sheath.

Aging↗
PubMed1986

Ethylene oxide neuropathy in rats. Exposure to 250 ppm.

In Wistar rats subjected to a 6-h exposure to ethylene oxide at the concentration of 250 parts per million once, 5 times a week for 9 months, histopathologic studies of myelinated fibers of the proximal sural, distal sural and peroneal nerves and of the fasciculus gracilis at the 5th thoracic and 3rd cervical segments of the spinal cord were performed to observe whether ethylene oxide of such a concentration would lead to degeneration of primary sensory neurons. Throughout the study, no definite abnormality of the gait or posture was observed in both control and test rats. Qualitative histologic studies disclosed preferential distal axonal degeneration of myelinated fibers in both sural nerves and gracile fascicles in the test rats, although the extent of the distribution and the severity of the degenerative findings were variable. Such findings are consistent with mild axonal degeneration found among patients suffering from ethylene oxide toxicity. Therefore, in rats, exposure to 250 ppm ethylene oxide produces central-peripheral distal axonal degeneration of primary sensory neurons.

Animals↗
PubMed1986

Scalp topography and distribution of cortical somatosensory evoked potentials to median nerve stimulation.

Topographies and distributions of cortical SEPs to median nerve stimulation were studied in 8 normal adults and 5 neurological patients. SEPs recorded from C4, P4, Pz, T6-A1A2 derivations to left median nerve stimulation were composed of 2 early negative (N16, N20) and 2 positive components (P12, P23), whereas those recorded from frontal electrodes (Fz, Fp1, Fp2) disclosed 2 early negativities (N16, N24) and 2 early positivities (P12, P20). N20 and P20, and P23 and N24, reversed across the rolandic fissure with no significant difference in their peak latencies. P23 was of slightly shorter latency at C4 than at more posterior electrodes (P4, T6, Pz). In 3 patients with complete hemiplegia but normal sensation, all the early SEP components were normal in scalp distribution and peak latencies except for a decrease of N24 amplitude. In 2 patients with complete hemiplegia and sensory loss no early cortical SEPs were seen. These findings suggest that N20 and P20 are generated as a single horizontal dipole in the central fissure, whereas P23 and N24 are a reflection of multiple generators in pre- and postrolandic regions.

Adult↗