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Biomedical subjects

T Hirabayashi

Publications and source records attributed to T Hirabayashi.

At least 109 records · Page 6Linked to original sources
PubMed1984

[Desorption behavior of carrier free tritium from the inner surface of a glass ampoule].

The desorption behavior of tritium from the glass ampoule which originally contained 37 GBq of carrier free tritium gas was studied by etching the surface with a diluted hydrofluoric acid solution or by heating at the constant rate up to 800 degrees C. The total amount of tritium sorbed on the inner surface of the ampoule was found to be 3.9 +/- 0.7 GBq. This value corresponded to more than 10% of tritium contained in the ampoule. The release rate of tritiated water (HTO) was 2.3 kBq/cm2.min, and the amount of HTO desorbed was strongly depended on the atmosphere. Thus, special precaution should be paid to the processing of a vessel once containing such an amount of tritium.

Adsorption↗
PubMed1983

Immunohistochemical localization of troponin-C in cultured neurons.

Our previous immunofluorescence studies on neurons have demonstrated the presence of myosin in regions of neurons which contained actin. To determine if a system similar to the troponin complex of striated muscle is present in neurons, antibody shown to be specific for the calcium-binding component of troponin (troponin-C) was applied to cultures of embryonic chick and rat dorsal root ganglia. Neurites treated with anti-troponin-C exhibited a bright fluorescence. Accompanying non-neuronal cells were less reactive than the neuronal elements. Immunodiffusion and immunofluorescence showed that the anti-troponin-C did not react with calmodulin, whereas homogenates of the ganglia elicited a positive immunochemical reaction with the anti-troponin-C in Ouchterlony tests. Our results suggest that some intra-axonal movements may be generated by the interaction of actin and myosin and controlled in part by a calcium-troponin-C-dependent mechanism.

Animals↗
PubMed1983

Developmental change of protein constituents in chicken gizzards.

Developmental change of protein constituents of chick gizzard smooth muscle was described by the fluorescent antibody technique and two-dimensional polyacrylamide gel electrophoresis. Myosin heavy chain, tropomyosin, and desmin were immunohistologically detected in 5-day-old gizzard primordia, but myoglobin was detected after 19 days of incubation. Two-dimensional polyacrylamide gel electrophoresis revealed that most structural proteins including beta- and gamma-actin are synthesized almost simultaneously in the primordium, and accumulate in three patterns by which the proteins examined are classified: (1) gradually increasing protein (gamma-actin, tropomyosin, desmin), (2) abruptly increasing protein at a certain stage (myosin, myoglobin), (3) decreasing or constantly kept protein (tubulin, beta-actin). Based on the quantitative analysis of protein constituents, the nature of regulatory system of protein synthesis in smooth muscle and the possible functional difference between beta- and gamma-actin are discussed.

Actins↗
PubMed1983

Investigation of actin in Tetrahymena cells. A comparison with skeletal muscle actin by a devised two-dimensional gel electrophoresis method.

Total protein constituents of Tetrahymena thermophila strain B1868 III were studied by two-dimensional agarose-polyacrylamide gel electrophoresis to detect actin among the constituents. In the attempts to prepare a whole-cell extract of Tetrahymena, it was found that protease activity in the extract was so high that high molecular components were quickly digested with the endogenous protease into small peptides unless the homogenization and heat-treatment in a sodium dodecylsulfate solution were performed within 5 s. It was eventually found that employment of 8 M guanidine hydrochloride (HCl) in the homogenization of cells perfectly prevented the degradation of protein components, even through a long preparation procedure. A devised two-dimensional agarose-polyacrylamide gel electrophoresis of the guanidine HCl extract gave a 'protein map' on which most proteins were located in their respective positions, including proteins with more than 200,000 mol. wt. Addition of rabbit skeletal muscle actin on the protein map revealed that no protein with isoelectric point and molecular weight identical with those of the actin was contained in the whole Tetrahymena extract, suggesting that Tetrahymena actin may have characteristics far different from those of skeletal muscle actin.

Actins↗
PubMed1983

Adenocarcinoma of the endometrium following prolonged use of an intrauterine device.

An Extremely rare case with the endometrial carcinoma induced by the prolonged (for 20 years) use of IUD (Oota Ring) was reported. The patient was a 57-year-old woman who visited our clinic claiming spotting, and the cancer was revealed by a D & C examination. Since no high risk factors for endometrial carcinogenesis were noted in this patient, it was inferred that prolonged use of IUD played an important role as a cocarcinogen. In particular, the mechanical action of the inserted IUD was thought to be responsible for carcinogenesis. The inflammatory reactions observed in the tumor tissues were considered to be the secondary changes induced by carcinoma.

Adenocarcinoma↗
PubMed1981

Tetrahymena calcium-binding protein is indeed a calmodulin.

We previously isolated a Ca2+-binding protein from a ciliate, Tetrahymena, and designated it as TCBP (Tetrahymena Ca2+-binding protein). The present paper reports that TCBP, which has two high affinity Ca2+-binding sites (Kd=4.6 X 10(-6) M), could activate porcine brain cyclic nucleotide phosphodiesterase at a concentration of over 10(-6) M free Ca2+, with the same mode of activation as that of authentic (porcine brain) calmodulin. In addition, the amino acid composition of TCBP was essentially the same as that of brain calmodulin. Therefore, we conclude that TCBP as an activator of Tetrahymena guanylate cyclase is indeed a calmodulin.

Amino Acids↗