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Y Ashitaka

Publications and source records attributed to Y Ashitaka.

9 recordsLinked to original sources
PubMed1991

Studies on the effect of thyroid hormone and epidermal growth factor on the cultured human cytotrophoblast.

We have previously reported that human placental cytotrophoblasts (C-cells) contain nuclear 3,5,3'-triiodo-L-thyronine (T3) receptors. Using a C-cell culture system, the present study was undertaken to clarify some of the effects of T3 and EGF on trophoblastic cells. C-cells were purified from human term placenta by treatment with trypsin-DNAse and percoll gradient centrifugation aggregated, then fused, differentiating into multinuclear syncytiotrophoblasts (S-cells) with incubation times up to 96 h in vitro. As the incubation time increased, the number of immunocytochemically reactive cells with antibodies to hCG-alpha, hCG-beta and hPL increased. Anti-EGF antibody reacted only with the initial C-cells, while anti-EGF receptor antibody reacted only with fused S-cells. Maximum secretion of hCG and hCG-alpha by the cultured cells was evident only when the cells were cultured in T3 (10(-8)M) or EGF (10 ng/ml) containing medium. When the initial cells were exposed to 10(-8) M T3 from 0 to 48 h of incubation, the secretion in 48-96 h was significantly accelerated. However, exposure from 48 to 96 h had no effect on peptide excretion. Although an exposure of these cells to 10 ng/ml EGF during 48-96 h of incubation stimulated the secretion of hCG and hCG-alpha, 0-48 h exposure did not produce any positive effect regardless of incubation time. These results indicated that the main target cell of T3 is the C-cell, while that of EGF is the S-cell. Furthermore, it is suggested that the interaction between T3 and its receptor facilitated functional cell differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1990

[Thyroid disease].

The incidence of pregnant women with thyroid dysfunction has been reported to be around 0.1-0.4%. Graves' disease accounts for more than half of these disorders. The main cause of thyroid disease in pregnancy and puerperium is autoimmune dysfunction. Whether there may be goitre or exophthalmus present, clinical signs as inappropriate weight gain, high systolic pressure, palpitation (greater than or equal to 110/min), emotional lability, fatigue, acceleration of suppression of the Achilles' tendon reflex should induce changes in the biochemical thyroid function tests. Parameters for the diagnosis and management for hyperthyroidism are serum levels of free T4 and TSH, while those of T3, reverse T3, and TSH are for hypothyroidism. Serum anti-microsomal antibodies and anti-thyroglobulin antibodies which have no effect on the fetus are also good markers for severity. The transplacental transfer of maternal TSH receptor antibodies consisting of stimulatory and inhibitory immunoglobulins and maternal thyroid-binding inhibiting immunoglobulins play roles in the development of transient neonatal hyper- or hypothyroidism. Fetal control is achieved by optimal maternal management. Untreated hyperthyroidism may be associated with fetal malformations. This risk may be reduced by antithyroid drug treatment of up to 150 mg/day of propylthiouracil which has less chance of placental passage and less secretion into the mother's milk than methyl-mercapto-imidazol. Maternal thyroid function should be kept in the upper limit of normal range, taking into consideration the fetal dysfunction induced by over-administration of the drug which passes through placenta. Children of hypothyroid women taking inadequate replacement therapy manifested lower IQ values compared to the progeny of euthyroid or hypothyroid women taking adequate therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithyroid Agents↗
PubMed1989

Studies on the nuclear 3, 5, 3'-triiodo-L-thyronine binding sites in cytotrophoblast.

Human placental trophoblasts contain 3, 5, 3'-triiodo-L-thyronine (T3) nuclear receptors not only at term but all throughout pregnancy. We determined which of the trophoblast, cytotrophoblast (C-cell) or syncytiotrophoblasts (S-cell) respond to thyroid hormone, and whether the T3 binding capacity changes with placental aging. Nuclear protein of mononuclear cells purified from term chorionic tissue by enzymatic digestion and Percoll gradient centrifugation had an apparent association constant (Ka) of 5.2 x 10(9)M-1 and a binding capacity of 445 fmol T3/mg DNA, 8 times greater than that of term trophoblasts. Primary harvested mononuclear cells reacted against neither anti-hCG-beta nor anti-hPL antibodies, although some of them reacted immunocytochemically against anti-hCG-alpha antibody. These cells aggregated with each other and transformed into multinuclear cells in culture after 96 hrs of incubation, showing that these primary harvested cells were C cells that had morphologically transformed into S cells. The transformed cells secreted hCG and hPL and immunocytochemically stained for these markers, suggesting that the C cells had functionally transformed into S cells. Nuclear binding of T3 in trophoblastic tissue is present not only at term but throughout pregnancy. Although each nuclei had a similar Ka value, the binding capacity decreased towards term. These findings suggest that nuclear T3 receptors of placental trophoblast change with placental aging and this change is mainly due to the change in the C/S cell ratio. We concluded that the cytotrophoblast is an active target cell of thyroid hormone.

Antibodies, Monoclonal↗
PubMed1979

The clinical evaluation of the simultaneous measurements of human chorionic gonadotropin (hCG) and its alpha-subunit in sera of patients with trophoblastic diseases.

The concentrations of human chorionic gonadotropin (hCG) and its free immunoreactive alpha-subunit (hCG-alpha) in the sera of patients with trophoblastic diseases were measured by hCG and hCG-alpha radioimmunoassay (RIA), respectively. In the sera of 12 women with hydatidiform mole large amounts of hCG and considerably high level of hCG-alpha were detected in all cases. After the evacuation of mole the serum level of these glycoproteins decreased, the leve of hCG-alpha declined more rapidly than hcg. in the sera of patients with destructive mole the concentration of hCG-alpha was usually lower than that of hCG. After hysterectomy and chemotherapy the levels of hCG-alpha declined practically paralleling that of hCG. However, when hCG had decreased to undetectable level, hCG-alpha could no longer be detected in all cases. Although in the serum of patient with choriocarcinoma involving the uterus and lungs the concentration of hCG-alpha was almost as high as that of hCG, the secretory pattern of hCG and hCG-alpha might not be closely related. The changes in the serum level of free hCG-alpha as well as that of hCG parelled the clinical course of the patients examined in this study. The present results suggest that measurements of the serum free hCG-alpha may be a useful parameter to follow the clinical course and to evaluate the efficacy of treatments of trophoblastic diseases.

Adult↗
PubMed1977

Alpha-subunit of human chorionic gonadotropin in fluid of molar vesicles.

Sera and fluid in molar vesicles from 4 patients with hydatidiform mole were analyzed for hCG and its subunits. These samples were initially chromatographed through a standardized Sephadex G-100 upward column. Starting materials and each fraction on gel filtration were radioimmunoassay in homologous hCG, hCG-alpha and hCG-beta assays. The specimens obtained from 4 patients contained primarily hCG and little hCG-beta. Immunoreactive hCG-alpha was barely detectable in sera but was clearly demonstrated in vesicle fluid from molar patients. This immunoreactive hCG-alpha was combined with [125I]hCG-beta. The combined protein, [125I]hCG and [125I]hCG-beta recombined with urinary hCG-alpha were concentrated in the superovulated rat ovary in vivo. However, [125I]hCG-alpha and [125I]hCG-beta were not taken up by the ovaries. The biosynthesis of hCG-alpha are discussed.

Animals↗
PubMed1975

Some biological properties of human chorionic follicle stimulating hormone.

The biological properties of human chorionic FSH (hCFSH) for rat ovaries were investigated. Highly purified hCFSH had similar response to the ovarian augmentation test as bovine FSH and significantly enhanced 3H-thymidine uptake by granulosa cells and theca cells in the ovary of hypophysectomized rat. In contrast, highly purified hCG little responded to the ovarian augmentation test and had no effect on 3H-thymidine uptake by the ovary. These results indicate that hCFSH may promote the follicular growth of ovary resulting from granulosa cell proliferation and its enlargement. In addition, freshly harvested porcine granulosa cells were employed in an in vitro system to investigate specific binding of hCFSH to ovarian receptor. Radioiodinated hCFSH (125I-hCFSH) and hCG (125I-hCG) were respectively incubated with cell suspensions. Binding of these hormone preparations was proportional to the cell number and increased with the time of incubation through 120 minutes. The binding ability of 125I-hCFSH to the cells was greater than that of 125I-hCG. Increasing concentrations of unlabeled hCFSH in the incubation mixture progressively inhibited the uptake of 125I-hCFSH by granulosa cells. Unlabeled hCG was not able to compete with 125I-HCFSH binding. The similar phenomenon to inhibit the binding of 125I-hCG to the cells was also recognized in the presence of unlabeled hCG. These findings suggest that granulosa cell has at least two different types of receptor sites: one for hCFSH and the other for hCG.

Animals↗