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Biomedical subjects

Y Kudo

Publications and source records attributed to Y Kudo.

At least 307 records · Page 17Linked to original sources
PubMed1987

Cell-mediated immunity caused by beryllium compounds.

Cells of spleen and lymph nodes were obtained from mice subcutaneously injected with BeCl2 once a week over a 6-week period. These cells were washed twice in cold phosphate-buffered saline and suspended at a final concentration of 2 x 10(7) cells in 1 ml of buffer. Subsequently, 0.5 ml of the suspension was injected into normal mice intravenously (passive transfer). The findings of the experiments using these mice are summarized as follows: (1) The footpad reaction test was performed 24 hrs after passive transfer. The mice receiving spleen cells or lymph node cells from mice sensitized with BeCl2 developed significant footpad swelling 24 and 48 hrs after challenge of BeCl2 as the antigen. (2) After passive transfer with sensitized spleen cells or lymph node cells the ears of the mice were painted with 7% BeCl2 in ethyl alcohol. Ears of these mice showed significant swelling as compared with those of controls. (3) The migration of peritoneal cells from mice receiving spleen or lymph node cells from sensitized mice was inhibited when tested in medium containing the antigen of BeCl2. From our present experiments, it was suggested that the beryllium sensitizing ability was related to active as well as passive cell-mediated immunity.

Animals↗
PubMed1987

[Immunological study of beryllium workers].

Immunological health surveys of Beryllium (Be) workers in a copper-beryllium casting factory were made 10 times during the 5-year period from 1981 to 1985. The total number of Be workers was 150. 1) Macrophage migration inhibition test was performed by an agarose plate method using Be as antigen with peritoneal cells from guinea pigs and small amounts of Be worker's blood. We found that 1 out of 22 healthy Be workers (4.5%) that migration index (MI) was below 80% after 24 h and 5 (22.7%) after 48 h. The mean of MI in Be workers showed significant low value as compared with that of the control group (p less than 0.01). 2) It was found that the serum complement titer tended to be lower in Be workers than in the control group. The serum complement titer of 3 to 6 subjects showed to be less than 30 U/ml every survey. 3) Although a few showed the abnormal levels in serum immunoglobin (IgG, IgA and IgE), the means of these immunoglobin levels were not markedly changed and they were in the normal ranges, respectively. 4) MI values significantly correlated with IgE level in Be workers, that is y= -8.9 x + 997.8 (r = -0.473, p less than 0.05). These results suggest that macrophage migration inhibition test and serum complement titer were of value for assaying of sensitivity to Be and immune responses in Be workers.

Beryllium↗
PubMed1986

The mechanism of calcium-independent catecholamine depleting action of monensin from clonal rat pheochromocytoma cells.

Monensin, a monovalent cation ionophore, induced profound release of radiolabeled materials from clonal rat pheochromocytoma cells (PC12h) preloaded with [3H]norepinephrine (NE). The release was suppressed in the absence of external Na+, but was not affected at all in the absence of external Ca2+. Cytosolic free Ca2+ concentration ([Ca2+]i), that was monitored by means of a fluorescent Ca2+ indicator, Quin 2, was temporarily increased upon a depolarizing stimulus of high-K+, which induced the Ca2+-dependent release of [3H]NE from PC12h cells. On the other hand, monensin induced only a slight increase in [Ca2+]i. The radiolabeled materials released by high-K+ treatment were mainly [3H]NE, whereas those by monensin were mainly the metabolites of [3H]NE. Pargyline, a monoamine oxidase inhibitor, suppressed both the degradation of [3H]NE stored in PC12h cells and the monensin-induced release of radiolabeled compounds from them. Monensin decreased the content of [3H]NE in storage granules of pargyline-treated cells. Thus, it is likely that monensin expels NE from the storage vesicles to cytosol and then its metabolites by monoamine oxidase are released in a non-exocytotic manner.

Adrenal Gland Neoplasms↗
PubMed1986

What determines the latency and amplitude of stationary peaks in far-field recordings?

In 20 radial nerves from 10 healthy persons, a referential derivation from the tip of the first or second digit registered two biphasic stationary peaks, PI-NI and PII-NII, following stimulation of the nerve in the forearm. These two peaks occurred slightly before the arrival of the propagating impulse at the wrist and at the base of the digit, respectively. With stepwise reduction of stimulation from a maximal to a threshold intensity, the far-field potential decreased in amplitude linearly with the near-field potential recorded at the junction of the volume conductor. Abduction of the first digit or flexion of the second and third digits altered the waveform and, to a lesser degree, the latency of the far-field peaks. However, these changes appeared in an inconsistent manner, which we were unable to characterize. We conclude that in far-field recording a stationary peak results at the border of the adjoining volume conductors in proportion to the magnitude of the propagating axonal volley approaching the boundary.

Adult↗
PubMed1986

Influence of indomethacin on an increase in cerebral blood flow induced by KC-404, a novel cerebral vasodilator, in an anesthetized dog.

The effect of KC-404 on vertebral blood flow in the absence and presence of indomethacin was investigated in an anesthetized dog. KC-404 (0.2 mg/kg, i.v.) showed a significant and long lasting increase in vertebral blood flow. This was markedly diminished by pretreatment of the animal with indomethacin. The increase in heart rate due to KC-404 administration was also diminished, though moderately, by pretreatment with indomethacin. From these results, the possible mechanism of action of KC-404 was discussed, particularly in reference to cerebral vasodilating prostaglandins.

Animals↗
PubMed1986

Anti-thrombotic effect of KC-404, a novel cerebral vasodilator.

KC-404 prevented mice from death and rats from A-V block, both induced by rapid i.v. injection of adenosine diphosphate (ADP), at high doses (5-100 mg/kg, i.v.). KC-404, at relatively lower doses (0.5-2 mg/kg, i.v.), inhibited the electroencephalographic (EEG) change in rat rapidly administered with arachidonic acid (AA) into the internal carotid artery. KC-404 (0.3-3 mg/kg, p.o.) inhibited the necrotic change of lower leg, paw or finger of rat when injected with sodium laurate into the femoral artery. KC-404 at doses up to 100 mg/kg, p.o. did not alter bleeding time in rat. Thus, KC-404 is expected to be of therapeutic value in cerebrovascular disorders accompanying thrombus in cerebral vasculature.

Adenosine Diphosphate↗
PubMed1986

Glutamate-induced increase in intracellular Ca2+ concentration in isolated hippocampal neurones.

A system for real-time quantitative monitoring of intracellular free calcium ion concentration ([Ca2+]i) on a single cell basis was developed by the combination of a fluorescent Ca2+ indicator fura-2, a fluorescence microscope, a video-camera and photometrical devices. It was applied to rat individual hippocampal neurones under culture for detection of L-glutamate-induced alterations in the [Ca2+]i level. L-Glutamate (0.01-100 microM) induced a dose-dependent elevation of the [Ca2+]i. The [Ca2+]i in the rat hippocampal neurone was found to be around 30 nM in the resting state, and was increased up to 500 nM by the application of 100 microM L-glutamate. N-methyl-D-aspartate, kainate and quisqualate in a concentration of 10 microM also increased the [Ca2+]i level in the same single neurone, but their efficacy varied between individual cells. The L-glutamate-induced [Ca2+]i elevation was abolished after removal of extracellular Ca2+ and was much reduced by Mg2+ (3 mM). The increase was, however, still observed in a Na+-free medium. The L-glutamate-induced [Ca2+]i elevation was not affected substantially after treatment with nitrendipine (10 microM) which blocked the increase in [Ca2+]i induced by an isotonic high KCl-medium (50 mM). The present results suggest that the L-glutamate-induced [Ca2+]i elevation in the hippocampal neurone is due to an influx of Ca2+ through both L-glutamate receptor-coupled and voltage-sensitive ionic channels.

Animals↗
PubMed1986

Hypergraphia: a right hemisphere syndrome.

A new right hemisphere symptom is reported. Five stroke patients with lesions in the perisylvian cortico-subcortical or thalamic region of the right hemisphere produced linguistically correct but semantically loose writing. The behaviour was initiated by subtle prompting and continued semiautomatically. A possible mechanism underlying this hypergraphia is discussed.

Aged↗
PubMed1986

Far-field recording of the junctional potential generated by median nerve volleys at the wrist.

In 20 arms from 10 healthy subjects, the orthodromic median sensory volleys crossing the wrist gave rise to a stationary, biphasic potential rendering the forearm initially positive (Pw) and subsequently negative (Nw) compared with the hand. A pair of electrodes located on each side of the wrist best detected the junctional potential, Pw-Nw, that developed across the partition. Here the hand and the forearm each, in effect, acted as a lead, connecting any points within the respective compartment to the voltage source. Thus, nearly the same potential difference appeared across the wrist regardless of the inter-electrode distance, allowing the detection of the voltage step in far-field derivation. Our data verify that not only positive but also negative peaks of scalp-recorded evoked responses could represent junctional potentials generated along the course of the conduction medium in the absence of fixed neural discharges.

Action Potentials↗
PubMed1986

Relation between size of compound sensory or muscle action potentials, and length of nerve segment.

In 24 median nerves from 12 healthy subjects, antidromic digital sensory potentials progressively diminished in size, averaging 40.4, 37.0, 30.7, and 23.9 microV X msec with stimulation at the palm, wrist, elbow, and axilla, respectively. In contrast, compound muscle action potentials changed minimally, measuring 19.4, 19.8, 19.0, and 18.2 mV X msec, respectively. Similar studies of the ulnar and radial nerves showed identical trends. Physiologic temporal dispersion can mimic conduction block of sensory nerves by summating the peaks of opposite polarity generated by fast- and slow-conducting axons. This type of cancellation affects muscle responses much less because motor unit potentials of longer duration superimpose nearly in phase, given the same latency shift as the sensory potentials.

Action Potentials↗
PubMed1986

Clinical correlates of abnormal P14 in median SEPs.

Recording median somatosensory evoked potentials (SEPs) from scalp and neck in separate channels with the use of an ear reference, 52 patients had abnormal scalp-recorded P14 associated with normal cervical-recorded N13. The patients had multiple sclerosis or other brainstem or high cervical cord lesions. Evidence of brainstem lesions was found in 35 patients on clinical examination or by brainstem auditory evoked potentials or blink reflex. Abnormalities of P14 were correlated highly with brainstem dysfunction, but high cervical cord lesions could not be excluded by this finding. The localizing value of SEP is improved by measuring the N13 and P14 peaks separately and assessing the cervical cord-brainstem conduction time.

Adult↗
PubMed1986

Monitoring of intracellular Ca2+ elevation in a single neural cell using a fluorescence microscope/video-camera system.

For monitoring the changes in intracellular free Ca2+ concentration ([Ca2+]i), we developed a simple system combining a fluorescence microscope, an image intensifier, a video-camera, a cathode ray tube display and a photodiode, employing quin2 as a Ca2+ indicator. We recorded increases of the fluorescence intensity due to [Ca2+]i rises, when high K+ medium, neurotransmitter and Ca2+ ionophore were applied to the single cells of nervous system origin in culture. The present system is capable of simultaneous detection of the [Ca2+]i changes from multiple separate cells.

Aminoquinolines↗