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Biomedical subjects

M Miyoshi

Publications and source records attributed to M Miyoshi.

At least 145 records · Page 8Linked to original sources
PubMed1980

[The effect of gamma-oryzanol on rat pituitary hormone secretion (author's transl)].

gamma-oryzanol (gamma-OZ), a ferulic acid ester of triterpene alcohol, was investigated with regard to its effect on pituitary LH, GH, prolactin and TSH secretion in normal male (M) and ovariectomized female (OVX) rats. gamma-OZ showed a suppressive tendency of LH by a single intravenous injection and also markedly reduced the LH release induced by LHRH when compared with only vehicle-dosed control groups in M and OVX rats. Serum prolactin release induced by TRH was markedly suppressed by 6 days pretreatment with gamma-OZ in OVX rats. These data suggest that gamma-OZ is a potent inhibitor of LH release and may be a weak inhibitor of prolactin in rats.

Animals↗
PubMed1980

Cytophilic antithyroglobulin antibody and antibody-dependent monocyte-mediated cytotoxicity in Hashimoto's thyroiditis.

Antithyroglobulin (anti-Tg) antibodies cytophilic for human monocytes were detected in the serum of 30 of 45 patients with Hashimoto's thyroiditis using the passive rosette technique. These antibodies conferred on normal monocytes the ability to form rosettes with Tg-coated erythrocyres (E-Tg) in vitro. The percentage of E-Tg rosette-forming monocytes was correlated with serum anti-Tg antibody titers measured by tanned sheep red cell hemagglutination. Most serum cytophilic activities were recovered in the immunoglobulin G fraction and were not affected by heating to 56 C for 30 min or ultracentrifugation at 105,000 X g for 60 min. Passive E-Tg rosette formation by monocytes was immunologically specific and was inhibited by the addition of small amounts of free Tg into the medium but was not inhibited by the addition of normal human serum. The anti-Tg antibody-armed monocytes became cytotoxic against Tg-coated chicken erythrocytes and lysed target erythrocytes by an extracellular mechanism. It was suggested that monocytes might be armed by cytophilic antibodies in vivo, since monocytes of patients with Hashimoto's thyroiditis showed increased E-Tg binding (rosette formation) relative to monocytes from control subjects. These findings support the possible pathogenetic involvement of monocytes in human autoimmune thyroiditis.

Animals↗
PubMed1979

Effects of nickel ion on the conduction of action potentials in non-myelinated nerve fibre of crayfish.

Effects of NiCL2 and PCMB (p-chloromercuribenzoate) on the action potential were examined by the method of extra- and intracellular electrodes, using a single nerve fibre of crayfish. The results obtained were as follows : The conduction of the action potential was blocked by treating the nerve fibre with Ni ion or PCMB. The blockade was easily recovered by replacement with cysteine. The process of the blockade and recovery, which could be repeated several times, was fairly characteristic such that the more repetition led the sooner blockade and the harder recovery. No conduction block was observed by treatment with Ni-cysteine mixed solution nor with PCMB-cysteine solution. The critical concentration for blocking was 1.1 x 10(-4)M for NiCL2 and 5.6 x 10(-6) M for PCMB. The action potential was disappeared without any change in the resting potential by treatment with the chemicals, which gave significant effects on the rising and falling phases of the action potential before the blockade.

Action Potentials↗
PubMed1979

Recurrent transient thyrotoxicosis with painless thyroiditis--a case report.

A case of a 40-year-old woman who was suffering from painless thyroiditis with recurrent transient thyrotoxicosis is reported. Acute exacerbations occurred four times during the past ten years, two after delivery and two after catching a cold. Serum thyroid hormones increased, though radioiodine uptake by the thyroid was very low and no inflammatory signs were observed. The histological findings of the thyroid were of atypical thyroiditis and not consistent with either chronic lymphocytic thyroiditis or subacute thyroiditis. Tanned sheep red cell hemagglutination titers for anti-thyroglobulin antibodies (TRC) and for anti-microsomal antibodies (MHA) were negative or low. The disease seems to be rare and the pathophysiology and etiology are discussed.

Adult↗
PubMed1978

Nuclear-magnetic-resonance study of aggregations and conformations of melanostatin and related peptides.

The 1H and 13C nuclear magnetic resonance spectra of melanostatin (Pro-Leu-Gly-NH2) and related peptides (Pro-Leu-Gly, Z-Pro-Leu-Gly, Z-Pro-Leu-Gly-NH2 and Z-Pro-Leu-Gly-OCH3, where Z = benzyloxycarbonyl) were analysed in a variety of solvents. At physiological pH, the melanostatin molecule is N-protonated in aqueous solution. The concentration dependences of the chemical shifts of amide-proton and carbonyl-carbon resonances and of proton spin-lattice relaxation times were observed in relation to molecular aggregations. In dimethylsulfoxide solution, aggregations were observed for N-protonated melanostatin and Pro-Leu-Gly prepared with HCl and for the Na salt of Z-Pro-Leu-Gly but not for N-protonated melanostatin prepared with HClO4 or HNO3, unprotonated melanostatin, Z-Pro-Leu-Gly-NH2, or Z-Pro-Leu-Gly-OCH3. The leucine NH and glycine CO groups of N-protonated melanostatin are involved in the intermolecular hydrogen bonds of aggregates. The leucine NH group of N-protonated Pro-Leu-Gly also forms the intermolecular hydrogen bond. The solvent and temperature dependences of the chemical shifts of amide-proton and carbonyl-carbon resonances were measured to determine intramolecular hydrogen bonding. In dimethylsulfoxide solution, N-protonated melanostatin molecules in part take the beta-turn structure and the trans carboxamide NH proton and carbonyl oxygen of the proline residue form an intramolecular hydrogen bond.

Glycine↗
PubMed1978

Hydrogen-deuterium substitution and solvent effects on the nitrogen-15 nuclear magnetic resonance of gramicidin S: evaluation of secondary structure.

Complete assignments of nitrogen-15 resonances of gramicidin S have been made in dimethyl sulfoxide, trifluoroethanol, and in a solvent mixture of dimethyl sulfoxide (50%) and methanol (50%). The assignments are achieved by utilizing the secondary structure of gramicidin S, by comparing the nitrogen-15 spectrum of gramicidin S with that of di-N-methylphenylalanine-gramicidin S and by taking into account the distinguishable value of nitrogen-15 chemical shift for valine in model compounds. Deuterium substitution for labile peptide protons was performed to delineate solvent shielded and deshielded peptide nitrogens and to substantiate further the signal assignments. The solvent titration on going from dimethyl sulfoxide to trifluoroethanol was also performed and shown to have a large deshielding effect on the peptide nitrogen whose corresponding peptide carbonyl, within the peptide moiety, was accessible to the trifluroethanol solvent.

Deuterium↗
PubMed1978

Scanning electron microscopy of the renal corpuscle of the mesonephros in the lamprey, Entosphenus japonicus Martens.

The renal corpuscle of the lamprey mesonephros was studied under the scanning electron microscope. Bowman's capsules with individual spaces are chockshaped sacs closely packed together along a medial artery. The lateral walls of the capsules are apposed to those of neighbouring capsules. Glomerular capillaries from the medial artery extend radially between the apposed walls of neighbouring Bowman's capsules. Bulgings of capillaries into the capsular space are associated with mesangial folds of the capsular epithelium. The transitional zone of the visceral layer with podocytes and the parietal layer of squamous epithelium is bounded by linearly arranged rod-shaped epithelial cells. Apertures of the urinary tubule are lined by cells equipped with a fascicle of cilia.

Animals↗
PubMed1978

Scanning and transmission electronmicroscopy of leukemic lymphoma cells without T- and B-cell surface markers.

The lymphoma cells from a patient with leukemia lymphoblastic sarcoma (Kiel classification) were observed by scanning and transmission electron microscopy. These cells were also examined by E, EA, EAC rosette-formation tests and by the indirect immunofluorescence technique for surface immunoglobulins. The malignant cells showed failure of rosette-formation or absence of surface immunoglobulins. Scanning electron microscopy revealed that many uniform protrusions were present on the cell surfaces. These surface protrusions were different from those seen on E-or EAC-rosette-forming cells. Ultrastructurally, the malignant cells were characterized by long profiles of rough surfaced endoplasmic reticulum with regular, narrow cisternae which radiated from Golgi area to the periphery of cytoplasm. These appearances differed from those observed in T-or B-lymphoma cells.

Adult↗
PubMed1978

The isolation and characterization of a trypsin inhibitor from Kintoki bean (Phaseolus vulgaris).

A trypsin inhibitor was isolated from beans of Phaseolus vulgaris, cultivar. Kintoki, and the specific activity increased 200 times as high as that of the crude extract. It was homogeneous on several electrophoreses and the molecular weight was about 13,000. The amino acid composition was characterized by high ratios of cystine, aspartic acid, and serine. It inhibited trypsin in a molar ratio of 1 : 1 and alpha-chymotrypsin in a molar ratio of 2 : 1. It, however, inhibited neither pepsin nor pronase. It was relatively stable to heat treatment in the acidic medium, but not in the alkaline medium. Neither pepsin nor pronase destroyed the inhibitory function.

Amino Acids↗
PubMed1977

[Detection of the antithyroglobulin antibody precipitated with polyethylene glycol (PEG) (author's transl)].

It is well known that the antithyroglobulin (anti-Tg) antibody plays an important role in the pathogenesis of autoimmune thyroiditis (chronic thyroiditis). The anti-Tg antibody is detected by double diffusion in agar gel, the fluorescent antibody technique and the tanned red cell haemagglutination test (TRC). The most widely used method is the TRC test, but it is negative in about 30 percent of the patients with chronic thyroiditis. In this paper, we have reported the detection of the anti-Tg antibody in serum using a modified Farr's method. In our method, PEG was used instead of ammonium sulfate to precipitate the immune complex formed in vitro between labelled Tg and the autoantibody. Percent 125I-Tg precipitated was 4.7 +/- 3.1 percent in normal controls; 20.4 +/- 11.4 percent in TRC negative sera were detected by this method. A good correlation was found between TRC titer and percent 125I-Tg precipitated by the PEG method in patients with chronic thyroiditis. By this method, the anti-Tg antibody was also detected in the sera of rabbits immunised with human Tg earlier than that detected by the TRC and double diffusion tests. The sensitivity and simplicity of this method provide a useful tool in detecting the anti-Tg antibody in clinical as well as in experimental work.

Animals↗