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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 1,009 records · Page 56Linked to original sources
PubMed1986

Effect of complement depletion by cobra venom factor on fowlpox virus infection in chickens and chicken embryos.

The course of infection with an attenuated strain of fowlpox virus (FPV), which is known to induce antibody-independent activation of complement via the alternative pathway, was investigated in 1- to 3-day-old chickens and 14-day-old chicken embryos by treatment with cobra venom factor (CVF). CVF was found to inhibit complement activity transiently via the alternative pathway but not via the classical pathway. In chickens treated with CVF, virus growth in the skin was enhanced, and pock lesions tended to disseminate, leading to fatal infection in some birds. Histologically, an acute inflammation at an early stage of infection (within 3 days) was inhibited, and virus content in the pock lesion was increased. In chicken embryos with immature immune capacities, CVF treatment caused changes in pock morphology from clear pocks to diffuse ones, an increase in virus content in the pock, and inhibition of cell infiltration. Thus, FPV infection was aggravated in both CVF-treated chickens and chicken embryos. These results are discussed in relation to roles of complement in the elimination of virus at an early stage of FPV infection.

Animals↗
PubMed1986

Determination of the source(s) of androgen overproduction in hirsutism associated with polycystic ovary syndrome by simultaneous adrenal and ovarian venous catheterization. Comparison with the dexamethasone suppression test.

To determine the source(s) of the excessive androgen production in patients with the polycystic ovary syndrome (PCOS), 12 hirsute women with PCOS underwent selective left adrenal and left ovarian venous catheterization. Blood samples were collected simultaneously for determination of cortisol, 17-hydroxy-progesterone, androstenedione (delta), testosterone (T), dehydroepiandrosterone, and dehydroepiandrosterone sulfate. The relative contributions of adrenal secretion rates of T and delta in each patient were estimated by relating their adrenal gradients to those of cortisol. From such calculations we found that in all patients the major source of androgens was the ovary (direct ovarian secretion and/or ovarian secretion of prehormones which then were converted to androgen in the peripheral circulation). After catheterization, 11 of the 12 patients underwent a 5-day dexamethasone suppression test (2 mg/day). In 7 patients studied, plasma delta and/or T levels decreased significantly. Our results indicate that in hirsutism associated with the PCOS, the predominant source of androgens is the ovaries and that glucocorticoid suppression cannot assign adrenal origin as the site of excessive androgens.

Adolescent↗
PubMed1986

Aromatization of norethindrone to ethynylestradiol in human adult liver.

Homogenates of human adult liver are capable of aromatizing norethindrone (17 alpha-ethynyl-19-nortestosterone) to ethynylestradiol (17 alpha-ethynylestradiol). The evidence of ethynylestradiol formation was obtained using a Bio-Rad AG1-X2 column, thin layer chromatographies and co-crystallization. Neither acid nor base was used in any step in product identification.

Adult↗
PubMed1986

Serum and urinary oestrone sulphate in pregnancy and delivery measured by a direct radioimmunoassay.

Serum and urinary levels of oestrone sulphate in pregnancy and delivery were measured by a direct radioimmunoassay without hydrolysis. The serum and urinary oestrone sulphate increased as pregnancy progressed. The mean level of serum oestrone sulphate increased to the highest peak of 494 pmol/ml at the 35th gestational week and then decreased. The mean level of urinary oestrone sulphate increased to the highest peak of 1.28 mumol/l at the 34th gestational week and then decreased. At vaginal deliveries, the mean level of maternal peripheral serum oestrone sulphate increased hourly at as high a level as 979 pmol/ml. The mean serum level of oestrone sulphate was 204 pmol/ml in the umbilical artery and 145 pmol/ml in the umbilical vein. At Caesarean section, on the other hand, the maternal peripheral serum level of oestrone sulphate averaged 362 pmol/ml. The mean serum levels of oestrone sulphate were 90.7 pmol/ml and 171 pmol/ml in the umbilical artery and umbilical vein, respectively. These results suggest a maternal origin of oestrone sulphate in pregnancy, with fluctuations in the levels being of interest in relation to labour pain.

Cesarean Section↗
PubMed1986

Concentrations of steroid receptors in normal human endometrium in relation to the day of the menstrual cycle.

Concentrations of receptors for estrogen (ER), progestin (PR) and androgen (AR) were measured in the cytoplasm and nucleus of human endometrium, throughout the normal menstrual cycle. Endometrial cellular ER and PR levels gradually increased during the preovulatory and immediate postovulatory phases, remained constant at the maximal level during the mid-secretory phase and gradually decreased to the lowest level at the end of the cycle. There was a difference between ER and PR nuclear levels in the mid-secretory endometrium, where maximum levels of PR and low levels of ER were noted. This PR abundance indicates the necessity of progesterone action for implantation. During the menstrual cycle, AR sites did not change noticeably and far fewer were found than those of the other receptors. This finding indicates that androgen plays a less important role in female reproduction.

Adult↗
PubMed1986

Inhibition by plant herb extracts of steroid bindings in uterus, liver and serum of the rabbit.

To assess the action of herb extracts, glycyrrhizin and paeoniflorin, upon steroids, their binding to several classes of intracellular and serum steroid-binding proteins was studied in the rabbit. Glycyrrhizin and paeoniflorin exhibited similar binding behaviors. They bound minimally to estrogen and androgen receptors, but not to the progesterone receptor in uterine cytosol, and exhibited a moderate binding activity to glucocorticoid receptors in liver cytosol. They also exhibited weak binding activity to both cortico-steroid-binding globulin and sex-hormone-binding globulin.

Animals↗
PubMed1986

Gestrinone (R2323) binding to steroid receptors in human uterine endometrial cytosol.

To understand the mechanism of biological action of gestrinone (R2323), which has a therapeutic effect against endometriosis, the binding of gestrinone to numerous classes of intracellular steroid binding proteins was studied in the human uterine endometrium. Gestrinone bound to endometrial receptors for estrogen, progesterone and androgen, but seemed not to bind to endometrial intracellular corticosteroid-binding globulin and sex hormone-binding globulin. Gestrinone occupies all specific binding sites of steroids in the steroid target cells despite the presence of endogenous steroids. It is speculated that the binding behavior of gestrinone may be related to its therapeutic effect on endometriosis. Gestrinone's more avid affinity for estrogen receptor may be the reason for the ability to use a lower clinical dose of gestrinone.

Cytosol↗
PubMed1986

Effects of streptonigrin derivatives and sakyomicin A on the respiration of isolated rat liver mitochondria.

Though all the streptonigrin derivatives with modifications in the carboxyl group on C2' were active as electron acceptors in the oxidation of NADH by Clostridium kluyveri diaphorase as well as streptonigrin, the glycine derivative did not show any marked effect on the KCN-insensitive oxidation of glutamate by rat liver mitochondria, suggesting a poor membrane transport of the glycine derivative. Sakyomicin A also induced the KCN-insensitive oxidation of glutamate by mitochondria, while a trace activity was observed by mitomycin C and the effect of doxorubicin was negligible. Like streptonigrin, the autoxidation of a reduced form (hydroquinone) of sakyomicin A to a quinone accompanied the generation of H2O2. However, exogenous NADH was oxidized by mitochondria in the presence of sakyomicin A but not streptonigrin.

Animals↗