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Biomedical subjects

N Satoh

Publications and source records attributed to N Satoh.

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

Cell- and tissue-specific monoclonal antibodies in eggs and embryos of the ascidian Halocynthia roretzi.

To obtain specific immunological probes for studying molecular mechanisms involved in the early embryonic development of ascidians, we have produced monoclonal antibodies directed against a homogenate of larvae of the ascidian Halocynthia roretzi. Among these, we have screened monoclonal antibodies that specifically recognize cells and/or tissues of the embryo. Characterization of six epidermis-specific monoclonal antibodies (including larval tunic-specific and larval fin-specific), three muscle-specific antibodies, two endoderm-specific antibodies, one notochord-specific antibody and two monoclonal antibodies that specifically recognize trunk-lateral cells suggests that these monoclonal antibodies may be useful as markers for analysing molecular mechanisms involved in specification of these cells. Seven monoclonal antibodies characteristically stain intercellular materials of the developing embryo and may therefore be valid for studying cellular construction of the embryo. Furthermore, monoclonal antibodies that recognize components of follicle cells, perivitelline space and sperm have also been established.

Animals↗
PubMed1987

Muscle cell differentiation in ascidian embryos analysed with a tissue-specific monoclonal antibody.

Utilizing a muscle-specific monoclonal antibody (Mu-2) as a probe, we analysed developmental mechanisms involved in muscle cell differentiation in ascidian embryos. The antigen recognized by Mu-2 was a single polypeptide with a relative molecular mass of about 220 X 10(3). It first appeared at the early tailbud stage and continued to be expressed until the swimming larva stage. There were distinct and separate puromycin and actinomycin D sensitivity periods during the occurrence of the antigen, suggesting the new synthesis of the polypeptide by developing muscle cells. Embryos that had been permanently arrested with aphidicolin in the early cleavage stages up to the 32-cell stage did not express the antigen. DNA replications may be required for the antigen expression. Embryos that had been arrested with cytochalasin B in the 8-cell and later stages developed the antigen, and the number and position of the arrested blastomeres exhibiting the differentiation marker almost corresponded to those of the B4.1-line muscle lineage. Furthermore, in quarter embryos developed from each blastomere pair isolated from the 8-cell embryo, all the B4.1 as well as a part of b4.2 partial embryos expressed the antigen, while the a4.2 and A4.1 partial embryos did not show the antigen expression. These results may provide further support for the existence of cytoplasmic determinants for muscle cell differentiation in this mosaic egg.

Animals↗
PubMed1987

[Effects of RU38486, an antiprogesterone agent, on endometrium, fertilized ovum and serum sex steroid levels in rats].

Effects of antiprogesterone RU38486 were studied in rats. The synthetic compound effectively (100%) inhibited implantation when administered on day 2 as well as on day 4 postconception (2.5mg/kg, in glycerol). This treatment, however, did not alter circulating estradiol and progesterone levels. Fertilized ovum yielded on day 4 from the uterine cavity showed normal morphology including adequate progress in cell division. A light microscopic study of the endometrium showed decreased cytoplasmic vacuole formation but estrogenic effects were apparently preserved. These data suggest that administration of RU38486 immediately after conception could successfully prevent implantation without altering early luteotropic functions in rats. Also the high dose of the compound was found to have no significant toxic effects on fertilized ovum, indicating that the anticonceptional action of RU38486 mainly functions at the uterine endometrial level.

Animals↗
PubMed1987

Cardiovascular pharmacology of 6-[4-(4'-pyridyl)aminophenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride, a novel and potent cardiotonic agent with vasodilator properties.

The cardiovascular profile of 6-[4-(4'-pyridyl)aminophenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride (MCI-154), a novel cardiotonic agent structurally different from cardiac glycosides and beta-adrenoceptor agonists, was investigated in vivo. In anesthetized, open-chest dogs, MCI-154 (0.3-100 micrograms/kg i.v., bolus injection) produced dose-dependent increases in dP/dtmax and cardiac output, and decreases in arterial blood pressure and total peripheral resistance with a relatively small increase in heart rate. The positive inotropic effect of MCI-154 was more potent than those of amrinone and milrinone. In anesthetized, intact-chest dogs, infusion of MCI-154 (0.3-3 micrograms/kg/min i.v.) also exerted a positive inotropic effect. P.o. administrations of MCI-154 (10-300 micrograms/kg) increased dP/dtmax in conscious beagle dogs. The cardiotonic effect of MCI-154 was not attenuated by blockade of autonomic receptors, catecholamine depletion and prostaglandin synthesis inhibition. MCI-154 (0.3-30 micrograms i.a.) produced a direct vasodilator effect in the canine hind-limb. MCI-154 (3 and 30 micrograms/kg i.v.) was effective in heart failure models induced with high doses of propranolol or verapamil. The potent cardiotonic and vasodilator activities of MCI-154 revealed by the present study suggest that this agent would be an effective remedy for the treatment of heart failure.

Anesthesia↗
PubMed1986

Inhibition of rat brain monoamine oxidase by some analogues of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 1-methyl-4-phenylpyridinium ion.

To clarify the essential chemical structures of the neurotoxins, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its oxidized product, 1-methyl-4-phenylpyridinium ion (MPP+), that govern nigrostriatal dopamine neuron toxicity, interactions of several structurally related compounds of MPTP or MPP+ with monoamine oxidase (MAO) in rat forebrain homogenates were studied. Of the compounds tested, 4-phenyl-1,2,3,6-tetrahydropyridine (PTP), 4-phenylpyridine and 4-phenylpiperidine strongly and dose-dependently inhibited MAO-A and -B activity. Inhibition of PTP and 4-phenylpiperidine was MAO-A-selective, while that by 4-phenylpyridine was MAO-B-selective. Of these 3 compounds, only PTP time-dependently inhibited MAO-B, but not -A. Without preincubation, the modes of inhibition of MAO-A and -B by PTP were competitive. After 1 h preincubation, the mode of MAO-B inhibition changed to non-competitive, while inhibition of -A remained unchanged. PTP was oxidized by MAO-B, but not by -A, under these conditions. In contrast, 4-phenylpyridine and 4-phenylpiperidine were not substrates for either form of MAO in rat forebrain homogenates. These results, along with the other observations, indicate that PTP may essentially cause a neurotoxic effect on the nigrostriatal dopamine pathway.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1986

Right hepatic lobectomy for primary lymphoma: a case report and literature review.

Primary lymphoma of the liver is an extremely rare entity; only eight cases have been reported in the literature. We treated a 34-year-old man with primary hepatic lymphoma by right hepatic lobectomy, including right hemicolectomy the nephrectomy. The histological diagnosis was a small cell diffuse histiocytic lymphoma. Details of this case plus that of others in the literature are described in this report.

Adult↗
PubMed1986

Light-induced potential and current across a large bacteriorhodopsin-asolectin planar membrane stabilized on a polyacrylamide gel surface.

A phospholipid bilayer membrane was spread from an organic solvent solution between a polyacrylamide gel surface and an aqueous buffer solution. The membrane was quite similar to the conventional black lipid membrane, but was of a large size and was stable since it was supported on the gel surface. Bacteriorhodopsin, impregnated into the membrane, generated membrane potential and current upon illumination. The induced current was large, and this was attributed to the large area of the present membrane. Remarkable responses of the light-induced potential and current were also observed with a thick layer of organic solvent containing phospholipids. The effects of applied membrane potential, carbonylcyanide-m-chlorophenyl hydrazone (CCCP) and gramicidin were examined on these photoresponses. Steady-state current, which is due to protons flowing through the membrane, was enormously enhanced by applying membrane potential opposite to the photopotential or by adding gramicidin to the membrane-forming solution.

Acrylic Resins↗