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Biomedical subjects

M Miyamoto

Publications and source records attributed to M Miyamoto.

At least 613 records · Page 34Linked to original sources
PubMed1979

[The incidences of spontaneous fetal anomalies in Japanese white rabbits (author's transl)].

The incidences of spontaneous fetal anomalies in coccidium-free Japanese white rabbits bred and kept in our laboratories are reported. Live fetuses were removed from 87 (95.6%) out of 91 maternal animals examined, totaling 538 (295 males and 243 females). of them, 9 fetuses (1.7%) showed external and visceral abnormalities such as hydrocephalia (5 cases), short tail (2), anophthalmia (1) and talipomanus flexa (1). Skeletal abnormalities were found in 7 (1.7%) of 424 fetues examined.

Animals↗
PubMed1979

[Establishment of a colony of Japanese white rabbits free from coccidia and their breeding performance (author's transl)].

A colony of rabbits free from coccidia was established in 1974 by weaning young at 25 days of age from dams infected with coccidia. Until now Bordetella, Pasteurella and Psoroptes cuniculi have not been detected either, and neither diarrhea nor death has occurred in weanlings of the colony. However, the mortality of sucklings was significantly high owing to cannibalism and tread by their dams. The weaning rate was effectively improved by use of a large nursing cage (3,100 cm2) and sterilized hay on a stainless steel mesh floor of the nursing cage.

Animals↗
PubMed1979

Regulation of the murine IgE antibody response. I. Characterization of suppressor cells regulating both persistent and transient responses and their sensitivity to low doses of X-irradiation.

Anti-ovalbumin (OA) IgE antibody responses were measured in B6D2F1 mice as a function of time and antigen dose. One hundred to 200 microgram of OA in Al(OH)3 elicited transient responses, whereas 1 to 10 microgram of OA in Al(OH)3 elicited persistent anti-OA IgE responses of high titer. T cells isolated from the spleens of mice mounting either a persistent or a transient response strongly suppressed primary anti-DNP IgE responses in unirradiated recipient mice that were immunized with DNP-OA in Al(OH)3; it was, therefore, concluded that suppressor T cells (Ts cells) were activated during both the persistent and transient IgE responses. Nevertheless, in the present study it was not possible to completely rule out the contention that IgG antibodies may also have been suppressing the IgE response. With a modified adoptive transfer system, it was shown that these Ts cells were sensitive to low doses (250 R) of x-irradiation. The suppressive activity of long-term OA primed cells was also shown to be markedly enhanced when cultured for 24 hr with soluble OA; this finding was interpreted to indicate the presence of memory suppressor cells.

Animals↗
PubMed1979

Lymphocytopoietic factor in lymph.

The evidences which suggest the presence of a lymphocytopietic factor in rat thoracic duct lymph are summarized briefly. The intravenous injections of the extracted materials from lymph plamsa into syngeneic recipient rats resulted in the massive proliferation of lymphoid cells predominantly in the thymus dependent areas and thymic cortex, suggesting that the target cells for the factor are not marrow-derived (B) cells, but thymus derived (T) cells. The existence of a thymus is not necessarily required for the production or secretion of the factor. The augmenting effect of the factor on T cell functions, eg. local graft-versus-host rection and helper activity of plaque forming response to sheep erythrocytes, is mentioned. The physicochemical characteristics of the factor are nondialysable and heat-stable glyco-protein molecules. The roles of lymph humoral factor in T cell-differentiation or proliferation are discussed.

Animals↗
PubMed1979

Excitatory effects of ergot alkaloids and their derivatives on the excitability of an identifiable giant neuron of the African giant snail (Achatina fulica Férussac).

The effects of various ergot alkalids and related substances on the neuronal excitability were examined using a spontaneously firing neuron (PON, periodically oscillating neuron) identified in the suboesophageal ganglia of the African giant snail (Achatina fulica Férussac). Of the substances examined, ergometrine and methylergometrine had a marked excitatory effect on the neuron (their critical concentration by bath application: 5 x 10(-6) kg/l). D-lysergic acid (the critical concentration: 3 x 10(-5) kg/l), D-lysergic acid amide (3 x 10(-5), D-lysergic acid 3-hydroxypiperidinamide (3 x 10(-5) and D-lysergic acid 4-hydroxypiperidinamide (10(-4) had also an excitatory effect which was weaker than that of the two alkaloids mentioned above. Agroclavine and elymoclavine had a very slight excitatory effect in some cases. The other substances examined, for example, lysergine, 9, 10-dihydro-D-lysergic acid, 9, 10-dihydro-D-lysergic acid amide, nicergoline, metergoline, methysergide, ergotamine, bromocriptine, lergotrile etc., had no effect on the neuron at a high concentration (10(-4) kg/l). When local (microdrop) application of ergometrine and methylergometrine in the physiological state was performed, the depolarizing shift of the PON membrane and exaggeration of the membrane potential oscillations were observed. In the Na+-free (replaced with Li+) state, local application of the two effective alkaloids produced a marked frequency increase of tonic spike discharges with depolarization of the neuronal membrane.

Animals↗
PubMed1978

Determination of 7-chloro-3-(4-methyl-1-piperazinyl)-4h-1,2,4-benzothiadiazine-1,1-dioxide (DU-717) in plasma using electron-capture gas chromatography.

A gas chromatographic method has been developed which enables accurate determination of a new antihypertensive agent, DU-717, in plasma. DU-717 is first extracted with ethyl acetate and, after a clean-up procedure, derivatized with peracetic acid followed by diazomethane to form 2-methyl DU-717 N-oxide (direct methylation leads to mixtures). The N-oxide is then pyrolyzed to 2-methyl DU-717 on a gas chromatograph equipped with electron-capture detection. Accurate determinations are possible over a concentration range from 10 to 150 ng/ml of DU-717 in plasma at a relative standard deviation of 6.2%. The minimum detectable concentration is 1 ng/ml. Plasma levels of DU-717 in spontaneously hypertensive and normotensive rats following single oral administrations (10 mg/kg) have also been determined.

Administration, Oral↗