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Biomedical subjects

M Miyake

Publications and source records attributed to M Miyake.

At least 343 records · Page 19Linked to original sources
PubMed1985

Enzyme immunoassay for elcatonin, a synthetic analogue of eel calcitonin, in plasma.

An enzyme immunoassay for the direct measurement of elcatonin, a synthetic analogue of eel calcitonin with hypocalcemic activity, in rat and dog plasma was developed. Elcatonin was conjugated to beta-galactosidase using an N-succinimidyl ester, and the product was used as the tracer. The antibody-bound tracer was precipitated using a second antibody. The nonequilibrated procedure gave better sensitivity and precision than the equilibrated procedure. The nonequilibrated method was sensitive at quantifiable concentrations as low as 0.2 ng/mL using 0.1 mL of plasma and was also reproducible, with RSD values generally less than +/- 10%. Plasma levels in rats and dogs were determined by this competitive enzyme immunoassay after intramuscular or intravenous injection of 40 U/kg (8 micrograms/kg) of elcatonin.

Animals↗
PubMed1985

Clonal sublines of rat neurotumor RT4 and cell differentiation. V. Comparison of Na+ influx, Rb+ efflux, and action potential among stem-cell, neuronal, and glial cell types.

A multipotential stem-cell-type cell line (RT4-AC) isolated from a rat peripheral neurotumor differentiates in culture into two neuronal-type cells (RT4-B and RT4-E) or into a glial-type cell (RT4-D). The neuronal classification of RT4-B and RT4-E cells is based on their positive response to veratridine in the tetrodotoxin-sensitive Na+-influx and Rb+-efflux assays and on the action potential observed upon hyperpolarized stimulation. In addition, these neuronal cell types do not synthesize two glial proteins, S100 protein (S100P) and glial fibrillary acidic protein (GFAP). The glial classification of RT4-D is based on the syntheses of S100P and GFAP. Additionally, RT4-D does not display veratridine-activated Na+ influx and Rb+ efflux nor action potential. The stem cell type, RT4-AC, expresses both neuronal and glial properties to a lesser degree. In the neuronal-type cell lines of the RT4 family (RT4-B and RT4-E), the large veratridine-activated Na+ influx can further be stimulated by scorpion toxin. The Na+ influx of the stem cell (RT4-AC), however, is only slightly stimulated by veratridine alone, but greatly stimulated by the addition of veratridine and scorpion toxin. These observations suggest that a progressive differentiation of voltage-dependent Na+ channels may have occurred by the cell-type conversion from the stem cell type to the neuronal cell types. The exact nature of the change in Na+ channels is currently not known.

Action Potentials↗
PubMed1985

Binding of the two components of C2 toxin to epithelial cells and brush borders of mouse intestine.

C2 toxin elaborated by Clostridium botulinum types C and D is composed of two nonlinked protein components and has enterotoxic activity, for which the cooperation of these two components is necessary. In the present study, the binding of components I and II, the two components of C2 toxin, to isolated epithelial cells and brush borders of mouse intestine was examined. Immunofluorescence studies showed that component II, either trypsinized (T-II) or untrypsinized (UT-II), bound to the cells and the brush borders of mouse intestine, whereas component I alone did not. The binding of I was observed only when the cells and the brush borders were reacted with T-II, but not when they were reacted with UT-II. These results are consistent with the fact that the biological activities of C2 toxin are elicited by the combination of I and T-II, but not of I and UT-II. The in vitro binding of I and II to isolated brush borders of mouse intestinal cells also showed similar binding characteristics. The binding of I and II to brush borders was rapid and not temperature dependent. Ultracentrifugal analysis revealed that both I and T-II bound to microvillous membranes of the intestinal cells. The data from the present study indicate that the enterotoxic activity of C2 toxin is initiated by the binding of T-II to the microvillous membrane of intestinal cells followed by that of I, for which the site of the cell membrane is induced by the binding of T-II, but not of UT-II.

Animals↗
PubMed1985

Measurement of the ratio of primary to total bile acids in serum by enzymatic fluorometric microassay and its clinical significance in patients with liver disease.

An enzymatic fluorometric microassay using 3 alpha- or 7 alpha-hydroxysteroid dehydrogenase was devised to determine serum total or primary bile acids. The present microassay using 50 microliter of a serum sample was run as a two-step method; the first step is the reaction of substrates with NAD+ and the hydroxysteroid dehydrogenase to produce as much NADH as possible in the incubation system and the second step is that of NADH with resazurin coupled with 1-methoxy phenazinemethosulfate to produce fluorescent resorfin. The assay is specific for 3 alpha- or 7 alpha-hydroxy bile acids, sensitive (a detection limit of 1.5 microM with a linear range of 1.5-80 microM), reproducible (CV = less than 5%) and inexpensive. As measured by this microassay, the ratio of serum primary to total bile acids (P/T ratio) in 10 normal subjects was 62.1 +/- 0.7% and was significantly elevated in the early phase of acute hepatitis (p less than 0.01), followed by return to the normal level after 4 weeks.

3-Hydroxysteroid Dehydrogenases↗
PubMed1985

[Diagnosis and treatment of mediastinal teratoid tumors].

Among anterior mediastinal tumors affecting male patients of around 20 years old, mediastinal malignant teratoid tumor must be considered as one of the possibilities. Malignant teratoid tumor can be classified as seminoma, non-seminoma or mixed, according to clinical behavior. In the non-seminoma group, AFP and/or HCG can be the specific markers in the diagnosis or assessment of the effect of treatment. Chemotherapy with CDDP must be the first choice of treatment in these types of tumor, just as chemotherapy is the first choice of therapy in the treatment of small cell lung cancer, and surgery must be the adjuvant treatment to chemotherapy. On the other hand, seminoma can be treated by surgery and radiation, which has been proven to yield a good prognosis. In cases of seminoma which produces HCG and/or AFP, chemotherapy with CDDP must be added to surgery and radiation as in non-seminomatous mediastinal teratoid tumors, because the production of such markers in seminoma is considered to be one of the poor prognostic factors in the treatment of seminomatous mediastinal teratoid tumors.

Adolescent↗
PubMed1985

Radiation-induced peroxidation of lipid dissolved in organic solvent and its inhibition by alpha-tocopherol and cepharanthine.

Effects of cepharanthine and alpha-tocopherol on radiation-induced peroxidation of lipids dissolved in methanol(MeOH)-chloroform (CHCl3)-H2O(v/v, 2/1/0.8) were examined. alpha-Tocopherol strongly inhibited radiation-induced peroxidation of lipids dissolved in MeOH-CHCl3-H2O. However, cepharanthine exhibited a weak inhibitory action in this system. The change in the absorption spectrum of alpha-tocopherol and cepharanthine by X-irradiation was measured. The reagents were dissolved in 95% EtOH acidified with 20 mM HCl and in MeOH-CHCl3-H2O. alpha-Tocopherol exhibited the change in its absorption spectrum in both systems, and seemed to be oxidized at a high rate by free radicals. However, cepharanthine slightly exhibited the change in its spectrum in MeOH-CHCl3-H2O, but not in acidified EtOH.

Alkaloids↗
PubMed1984

A rapid and sensitive method for the determination of hypusine in proteins and its distribution and developmental changes.

A simple and sensitive method for determining hypusine in proteins was developed. A greater part of amino acids in the acid hydrolysate of proteins was separated from hypusine by treatment with an ion-exchange resin. The sample containing partially purified hypusine was then analyzed by high-performance liquid chromatography using the post-column derivatization method with o-phthalaldehyde. The recovery rate of hypusine through the overall procedure was more than 95%. Using this method, the distribution and developmental changes of hypusine in proteins were determined. The amino acid was found in proteins of all examined organs of rat. Its concentration was 5-40 nmol/g protein. The subcellular distribution in rat liver was also determined. About 60% of total amount of hypusine was present in the proteins of cytoplasmic and microsomal fractions and its relative concentration was high in the proteins of microsome and lysosome and low in mitochondria. In developing rat, the concentration of hypusine in the brain proteins was relatively high during the first 2 or 3 weeks of postnatal life and then decreased until adulthood. Its concentration in the liver proteins was highest at birth and then decreased continuously to the adult level.

Animals↗
PubMed1984

Contribution of surface potential to resting potential in mouse neuroblastoma cells: estimation with fluorescent dyes and from shift of threshold potential for Ca-spike.

The contribution of the changes in the diffuse double layer potential (surface potential) to the resting membrane potential of the mouse neuroblastoma (N-18 clone) was estimated with the use of fluorescent dyes and from the shift of the threshold potential of the Ca-spike. The membrane potential monitored by Rhodamine 6G was unchanged with variations of external K+ concentration [( K+]o) below about 10 mM, and changed linearly with log [K+]o above this concentration, similar to the changes observed with a microelectrode. This result indicates that the independence of the membrane potential of [K+]o at low [K+]o is not brought about by the artifacts caused by insertion of a microelectrode into the cell. The changes in the surface potential in response to various polyvalent cations (Mg2+, Ca2+, Mn2+, Cd2+ and La3+) were monitored by the fluorescence of ANS. The behavior of the surface potential thus observed was closely correlated with that of the membrane potential for the respective polyvalent cations. The surface potential changes in response to increase in [Ca2+]o from 1.8 to 100 mM and in [Mg2+]o from 0.8 to 100 mM were 88% and 85% in magnitude compared with the corresponding changes in the membrane potential, respectively. The effect of variation of [Ca2+]o on the threshold potential of the Ca-spike was compared with that of [Ca2+]o on the resting membrane potential. The magnitude of the surface potential change determined by the shift of the threshold potential was comparable to the magnitude of the membrane potential change. The results in the present study suggest that the surface potential change produced at the membrane surface of N-18 cells is detected as a transmembrane potential change without a large reduction in magnitude.

Anilino Naphthalenesulfonates↗
PubMed1984

Oral surgery and hemodialysis.

A case of a hemodialysis patient with a palatal tumor is presented. The problems requiring surgical management were as follows: anemia, hyperkalemia, bleeding tendency, delayed wound healing and usage of drugs, especially antibiotics. The palatal tumor was diagnosed histologically as monomorphic adenoma.

Adenoma↗
PubMed1984

Study of the mechanism behind adjuvant action of diethylethoxymethylene malonate enhancing the rectal absorption of cefmetazole and lysozyme.

Diethylethoxymethylene malonate (DEEMM) and diethyl maleate (DEM) enhanced the rectal absorption of cefmetazole in rats when studies were carried out using in vivo, in situ rectal loop and in vitro rectal everted sac method. Since an increase of cefmetazole transport was found when concentration of nonprotein sulfhydryls in rectal tissue was decreased by the presence of either DEEMM or DEM in the study using in vitro everted sac method and the enhancement of cefmetazole absorption by the coadministration of either DEEMM or DEM was suppressed by the treatment with dimercaprol, membrane permeability of rectal tissue seems to be regulated by the concentration of nonprotein sulfhydryls in rectal tissue. On the other hand, it was also found that there were differences between the action of DEEMM and the action of DEM from the following two results: 1) enhancing action of DEEMM was suppressed by the presence of calcium ion in microenema while action of DEM was not so much influenced, and 2) DEEMM enhanced the rectal absorption of lysozyme in rabbits but DEM did not.

Adjuvants, Pharmaceutic↗