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Biomedical subjects

T Masaki

Publications and source records attributed to T Masaki.

At least 541 records · Page 30Linked to original sources
PubMed1980

Types of myosin light chains present during the development of fast skeletal muscle in chick embryo.

The types of myosin light chains in developing fast skeletal muscle of chick embryo were characterized in terms of their mobilities on SDS-polyacrylamide gel electrophoresis and their reactions with antisera against adult fast, slow, or cardiac myosin light chains. Breast and leg muscles of adult chicken mainly contain fast-type myosin, while at early developmental stages, these muscles contain four classes of light chain as judged by SDS-polyacrylamide gel electrophoresis and immunoelectrophoresis; two of these light chains are of the slow and/or cardiac type and the other two are of the fast type. At late developmental stages, fast-type light chains are present in large amounts and slow and/or cardiac light chains exist only in small amounts. It is suggested that the qualitative changes in light chains during embryonic development are coordinated with those in heavy chains reported by Masaki and Yoshizaki (5).

Animals↗
PubMed1980

Presence of smooth muscle myosin-like protein on liver cells.

Antiserum against purified chicken smooth muscle myosin was obtained from rabbits. The serum was specific for smooth muscle myosin and did not react with myosins from fast and slow skeletal muscle or cardiac muscle. Using this specific antibody, the location of smooth muscle myosin-like protein was studied by double antibody immunofluorescence microscopy with sections of chicken liver tissue. Marked fluorescence was demonstrated along the sinusoids of hepatic tissue and the vascular walls. The findings in this study suggest that a myosin-like protein, which is immunologically similar to the myosin from smooth muscle but not to myosins from skeletal or cardiac muscle would exist on the sinusoidal surface of liver cells.

Animals↗
PubMed1980

Extractability of actin and actin-like protein from myosin-removed myofibrils of skeletal muscle.

Extractability of 42,000 dalton components (42 K component) from myosin-removed myofibrils (called I-Z-I segments in this paper) under low-salt conditions was compared at pH 6.5 and pH 8.0. Kinetic and isoelectric focusing analysis of the 42 K components revealed that the 42 K component extracted at pH 8.0 was actin, which depolymerized from the end of the I-filaments of the I-Z-I segments. On the other hand, isoelectric focusing of the 42 K component extracted at pH 6.5 indicated two protein bands. The relative mobility of the minor band was virtually identical to that of actin. While the isoelectric point of the major band was more acidic than that of skeletal muscle actin. Therefore, it is concluded that there are at least two kinds of 42,000 dalton components in the myosin-removed myofibrils.

Actins↗
PubMed1979

Anti-androgen TSAA-291. III. Hormonal spectra of anti-androgen TSAA-291 (16 beta-ethyl-17 beta-hydroxy-4-oestren-3-one) and its derivatives.

For the purpose of obtaining hormonal spectra of anti-androgen TSAA-291 and its derivatives, a variety of endocrine characteristics were studied. (1) Androgenic and anabolic activity : Subcutaneous administration of anti-androgen TSAA-291 and its acetate, TSAA-328, to the immature orchiectomized rat resulted in significant weight increase of the levator ani but in only a nominal response of seminal vesicles and prostates even at a large daily dose of 9.6 mg. The resultant anabolic/androgenic ratio was estimated to be extremely high. (2) Oestrogenic activity : Uterine weight in response to these anti-androgens were sluggishly dose-dependent, and the maximal plateau response remained considerably lower than that induced by oestradiol-17 beta. The oestrogenic activity of these anti-androgens was estimated to be 1/200 000 or less as that of oestradiol-17 beta. A single subcutaneous dose of 100 mg of TSAA-291 or its caproate, TSAA-330, did not induce the vaginal cornification in the adult ovariectomized rat. (3) Anti-oestrogenic activity : Antagonistic effect of these anti-androgenic compounds on the uterine weight response to oestradiol-17 beta was found in the immature ovariectomized rat. A single subcutaneous dose of 100 mg of TSAA-291 or TSAA-330 also induced the antagonism against the cornification caused by daily treatments with 1 microgram oestrone in the adult ovariectomized rat. (4) Progestational activity : These anti-androgenic compounds proved to be less active than progesterone in the McPhail's test. (5) Anti-inflammatory activity : Daily subcutaneous dose of 20 mg of TSAA-291 for 6 days did not significantly depress the weight of granuloma developed around the cotton-pellet implanted in the young male rat. TSAA-291 did not affect the anti-inflammatory action of 1/6 mg of prednisolone phosphate. Combination of both agents seemed to be effective in enhancing the anti-androgenic action of TSAA-291, whereas prednisolone phosphate alone rather increased the weight of the accessory sex organs. (6) Liver glycogen deposition activity : Daily intramuscular doses up to 38.4 mg of TSAA-291 for 5 days did not increase the liver glycogen level in the adrenalectomized rat.

Androgen Antagonists↗
PubMed1979

Denervation-like supersensitivity in the rat vas deferens induced by local application of colchicine to the hypogastric plexus.

In an attempt to induce denervation-like supersensitivity in the smooth muscle of the vas deferens without depriving the tissue of its innervation, a small amount of colchicine was locally applied to the hypogastric plexus of the rat. Colchicine produced supersensitivity and a partial depletion of the tissue norepinephrine. These effects were dose-dependent. The supersensitivity produced by colchicine was qualitatively and quantitatively similar to that induced by denervation. Following application of 20 micrograms of colchicine, the supersensitivity was fully developed by the 4th day. The supersensitivity began to decline by the 6th day but was measurable even after 16 days. Functional neuromuscular transmission was maintained even on the 4th day after colchicine application, although it was significantly less than the control. The time course of the development of supersensitivity was dependent on the length of the adrenergic nerve between the colchicine-applied site and the effector cells. The results indicate that supersensitivity is independent of an irreversible degeneration of the adrenergic nerves. The possible mechanisms of action of colchicine are discussed in relation to the known effects of colchicine on axoplasmic transport.

Animals↗
PubMed1979

Immunochemical comparison of myosin light chains from chicken fast white, slow red, and cardiac muscle.

Antibodies were formed against the myosin light chains isolated from chicken fast skeletal, slow skeletal, and cardiac muscle and the antigenicities of the light chains were compared by double immunodiffusion and immunoelectrophoresis. It was shown that fast light chains are immunologically different from light chains of slow and cardiac myosin, while the slow and cardiac muscle light chains have similar immunological characteristics; that is, the light chains of apparent molecular weight about 27,000 daltons in SDS-acrylamide gel electrophoresis of slow and cardiac muscle are immunologically indistinguishable, and the other light chains of apparent molecular weight about 19,000 daltons of both muscles include a common antigenic site.

Animals↗
PubMed1979

Anti-androgen TSAA-291. I. Anti-androgenic effects of a new steroid TSAA-291 (16 beta-ethyl-17 beta-hydroxy-4-oestren-3-one) and its derivatives.

Anti-androgenic properties of newly synthesized steroidal compounds, TSAA-291 and its derivatives, were studied in the rat. (1) Subcutaneous administrations of TSAA-291 and TSAA-272 were effective in depressing the weight of seminal vesicles and ventral and dorsal prostates in the adult rat. (2) TSAA-291, TSAA-328 and TSAA-272 were shown to be anti-androgenic by the subcutaneous or oral route in the immature castrated male rat treated with testosterone propionate. The dose-response curves of all the test agents expressed in terms of percentage inhibition were approximately parallel to each other. Cyproterone acetate depressed the weight of levator ani muscle dose-dependently, whereas TSAA-291, TSAA-328 and TSAA-330 did not inhibit the muscle weight in a dose range sufficiently effective in inhibiting the weight of seminal vesicles and ventral and dorsal prostates. (3) TSAA-291 was also anti-androgenic against androstenedione and dehydroepiandrosterone. (4) Local administration of the anti-androgenic compounds into the left seminal vesicle or left testis of the young adult rat depressed the weight of the seminal vesicle or testis on the treated side as compared with the vehicle-injected contra-lateral side.

Androgen Antagonists↗