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Biomedical subjects

Y Hamada

Publications and source records attributed to Y Hamada.

At least 541 records · Page 30Linked to original sources
PubMed1981

[Effects of dehydroepiandrosterone sulfate on serum steroid hormones in pregnant rabbits (author's transl)].

After the administration of dehydroepiandrosterone sulfate (DHAS) (0,10,30,70 mg/kg, i.v.) to rabbits during late pregnancy, serum concentration of DHAS, dehydroepiandrosterone (DHA), testosterone (T), estradiol (E2) and progesterone (Prog) were determined by radioimmunoassay. Serum levels of DHAS increased dose-dependently, and were reduced biphasically to normal levels at 24 hr after the administration. Similarly, the levels of DHA, T and E2 increased, and reached the maximum at 30 min after, though the increase of DHA or T was one-thousandth that of DHAS, and that of E2 was about one-hundred-thousandth. On the other hand, Prog concentration in sera decreased to 50 approximately 60% of that before the injection at 30 min after (p less than 0.05). These results suggest that the changes observed in E2 and Prog levels after the injection of DHAS into pregnant rabbits corresponded to the changes of endogeneous E2 and Prog seen in early parturition in women.

Animals↗
PubMed1980

Inhibitory effect of prolactin on ovulation in the in vitro perfused rabbit ovary.

Prolactin is best known for its effects on the breast, promoting mammary growth and lactation. In some species, including rat, mouse, hamster, sheep and rabbit, prolactin is necessary for the maintenance of the corpus luteum. Further, a relationship has been recognised between hyperpromus and or adenohypophysis. McNatty et al. have postulated a direct ovarian effect of prolactin, reporting that low prolactin levels were essential for progesterone production by preovulatory human granulosa cells cultured in vitro. However, high levels of prolactin decreased progesterone production. The present investigation sought to determine the effect of prolactin on ovulation using the in vitro perfused rabbit ovary preparation. We report that its effects are inhibitory.

Animals↗
PubMed1980

Chemicals which promote survival of ultraviolet-irradiated lon and ruv mutants of Escherichia coli K12.

The effects of postirradiation incubation with various chemicals structurally related to pantolactone on the survival of ultraviolet-irradiated Escherichia coli lon and ruv mutants were examined. Certain cyclic compounds with a butyrolactone, tetrahydrofuran, furan, tetrahydropyran, or 2-pyron ring showed substantial rescue activity in lon and (or) ruv mutants. In addition, several aliphatic, monocarboxylic acid salts, including hydrolysis products from pantolactone and butyrolactone, were also active in one or both of these mutants, especially pantoate and other hydroxy acid salts in the ruv bacterium. The two mutants differed considerably in their susceptibility spectra for the rescue actions of these compounds.

4-Butyrolactone↗
PubMed1980

Simple pelvic arteriography using a disposable elastic vein needle.

A new method for pelvic arteriography using a disposable elastic vein needle is presented. The technique is carried out by percutaneous transfemoral artery puncture and contrast medium is injected by a power air-driven injector which makes bilateral pelvic arteriography possible. Neither a radioopaque long catheter nor a guide wire are necessary in the present method. No major complications have been observed in a series of 162 cases. The present method is advantageous due to its simplicity and safety compared with ordinary Seldinger's method which is not always free of complications.

Angiography↗
PubMed1980

[Effects of dehydroepiandrosterone sulfate on serum steroid hormones and endocrine organs in adrenalectomized immature female rats (author's transl)].

SD female rats were bilaterally adrenalectomized or sham-operated at the age of 20 days and were given dehydroepiandrosterone sulfate (DHAS; 50 or 100 mg/kg body wt. p.o.) for 7 days. Twenty-four hours after the last administration the animals were sacrificed and levels of serum estrone, estradiol, estriol, testosterone (T), progesterone(P), aldosterone, 11-OH-corticosteroid (11-OH-CS), dehydroepiandrosterone (DHA) and DHAS were determined. Uterus, ovary, pituitary gland, thyroid, thymus, liver and kidney were weighed and examined histologically. Adrenalectomy significantly reduced serum levels of T, P, aldosterone, 11-OH-CS, DHA and DHAS organ weights of liver and kidney, and increased the weight of the thymus. In sham-operated rats, DHAS increased weight of the uterus and serum DHAS level while the other hormones and organs were not affected. In the adrenalectomized rats, DHAS increased the serum levels of DHAS and T, weight of the uterus and inhibited increase in the weight of the thymus. These findings suggest that DHAS-induced increases in the weight of uterus are not affected by endogenous hormones secreted from the adrenal gland.

Adrenalectomy↗