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Biomedical subjects

Y Ibuki

Publications and source records attributed to Y Ibuki.

At least 145 records · Page 8Linked to original sources
PubMed1987

Pituitary enlargement with target organ deficiency: hypothyroidism and hypogonadism.

Three women with pituitary enlargements associated with preexisting target organ failures are reported. Two pituitary enlargements owing to primary hypothyroidism and one to primary hypogonadism were shown to be regressed on computed tomography after the replacement therapy. Clinically and pathologically, the differentiation of a pituitary hyperplasia from a pituitary adenoma is often very difficult. Moreover, the treatments for these conditions are quite different. Adequate medication can diminish a pituitary enlargement because of the feedback mechanism. Existence of the target organ deficiency should always be checked before the management of pituitary tumor.

Adult↗
PubMed1987

Action mechanism of inhibin in vitro--cycloheximide mimics inhibin actions on pituitary cells.

The effects of inhibin on gonadotropin secretion from cultured rat anterior pituitary cells were examined by using purified porcine follicular fluid (pFF) 32 kDa inhibin. pFF 32 kDa inhibin suppressed the basal FSH secretion as well as cell content of FSH with identical ED50 values (ED50 = 1.0 ng/ml) in a dose-dependent manner, but did not alter either basal secretion or cell content of LH. On the other hand, pretreatment of the pituitary cells with pFF 32 kDa inhibin during the first 3 days resulted in suppression of subsequent LH-RH-stimulated release of both FSH and LH in a dose-dependent manner, indicating that the suppression of LH-RH-stimulated release of LH is one of the intrinsic inhibin actions on pituitary cells. The marked difference between ED50 values for FSH (ED50 = 1.1 ng/ml) and LH (ED50 = 2.5 ng/ml) in the suppression of LH-RH-stimulated release of gonadotropins, together with the fact that the total amount of LH (cell content plus released) after LH-RH stimulation remained unchanged following inhibin treatment suggests that the suppression of LH-RH-stimulated release of LH by inhibin is quite different from that of FSH regarding the action mechanism. Similarly, cycloheximide, an inhibitor of protein biosynthesis, suppressed both basal secretion and cell content of FSH with almost the same ED50 values (ED50 = 22.5 ng/ml) but did not alter either basal secretion or cell content of LH. Cycloheximide also suppressed LH-RH-stimulated release of both FSH and LH, and the ED50 values were different from each other (ED50 = 25.0 ng/ml for FSH and 60.0 ng/ml for LH suppression, respectively). Our finding that cycloheximide completely mimicked the action of inhibin on gonadotropin secretion strongly suggests that LH is quite insensitive to biosynthetic inhibition, and that preferential effects of inhibin or cycloheximide on FSH in appearance may reflect the difference between LH and FSH in susceptibility to biosynthetic inhibition.

Animals↗
PubMed1987

Regulation of inhibin production by rat granulosa cells.

Inhibin production by cultured granulosa cells from immature diethylstilbestrol (DES)-primed rats was studied in relation to estradiol and progesterone production. The inhibin content in culture media was assayed with a specific radioimmunoassay (RIA) using an antibody to porcine 32 kDa inhibin that recognizes rat inhibin as well. Inhibin production was about 10 ng/ml/2 X 10(4) cells/72 h at the basal levels and was maximally stimulated with 25 ng/ml of follicle stimulating hormone (FSH) to 45 ng/ml which was 4.5 times the basal levels, with an ED50 value of 2.0 ng/ml. A cyclic AMP analog (dibutyryl cyclic AMP) or reagents that promote cAMP production were also effective in inhibin production, indicating that FSH stimulates inhibin production through a cAMP-dependent pathway. Luteinizing hormone (LH) was not effective in producing inhibin from freshly prepared granulosa cells, whereas granulosa cells pre-incubated with FSH for 48 h because responsive to LH regarding inhibin production. Testosterone sensitized the granulosa cells to the FSH stimulation, whereas hydrocortisone (4 ng/ml) decreased the sensitivity of granulosa cells by increasing the ED50 value for inhibin production by FSH about 10 times. A similar effect was observed regarding estradiol production, while progesterone production due to stimulation by FSH was enhanced by the hydrocortisone treatment. Insulin and platelet extract both stimulated inhibin production and enhanced the maximal response of inhibin production due to stimulation by FSH without altering, or even increasing the ED50 values. Epidermal growth factor (EGF), (D-Leu6)Des-Gly10-LHRH N-ethylamide (GnRH agonist) and 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent protein kinase C activator, inhibited both inhibin production and estradiol or progesterone production. Consequently, the regulation of inhibin production was similar to that of estradiol production, but markedly different from that of progesterone. However, inhibin and estradiol production were modulated differently by various growth factors and hormones. These phenomena might account for possible discrete changes in the plasma levels of inhibin and estradiol in vivo.

Animals↗
PubMed1987

A clinical evaluation of transcatheter arterial embolization on hepatocellular carcinoma.

TAE was performed in 49 cases of HCC for clinical assessment of the usefulness. This procedure was aimed to subside intraperitoneal hemorrhage in 8 cases among them and to provide a possible antitumor effect in the remaining 41 cases. The prognosis in the 8 cases of intraperitoneal hemorrhage was 54.9 +/- 41.1 days including one case survived as long as 116 days. The prognosis in the remaining 41 cases was 12.6 +/- 8.3 months in group A, 7.8 +/- 6.1 months in group B and 1.6 +/- 1.3 months in group C according to Child's classification, while it was 2.8 +/- 2.5 months in 1st branch occluded, 9.4 +/- 6.1 months in IInd branch occluded and 19.2 +/- 6.7 months in IIIrd branch occluded group according to the portal vein occlusion due to tumor thrombi suggesting that a more prolonged survival was attained with more favorable degree of Child's classification and less affected portal embolization. The cumulative survival time (by Kaplan-Meier's methods) was 6 months in 89% of the cases examined, 1 year in 59%, 2 years in 34% and 3 years or more in 11%, indicating significantly higher survival as compared to our TAI group. Angiographic re-opening of tumor vessel within 3 months was observed in 46.7%. TAE on HCC was useful both for the purpose of antitumor effect and of hemostasis. The degree of Child's classification and severity of portal occlusion at the initial examination may closely relate to the prognosis. Thus, angiography should be repeated within 3 months following the first TAE at least.

Adult↗
PubMed1987

[Endocrinological background of pituitary desensitization during pulsatile LH-RH therapy for ovulation induction in amenorrheic women].

In order to elucidate the endocrinological background of patients in whom ovulation induction by pulsatile LH-RH administration resulted in failure, 16 women with hypothalamic amenorrhea were treated with 10 to 20 micrograms of LH-RH injected subcutaneously every 2 hrs. Six women did not ovulate, and 5 of them showed pituitary desensitization since the basal gonadotropin concentration gradually decreased and the response to LH-RH test (100 micrograms i.v.) became blunted by the treatment. No significant differences between the ovulated and desensitized groups were seen in basal LH, FSH, E2, PRL levels, LH/FSH ratio and response to LH-RH test performed prior to the treatment. In addition, the plasma LH-RH profile after subcutaneous injection of 10 micrograms of LH-RH was highly pulsatile in both groups. However, in the desensitized group, all were obese, showed impaired GH response to both insulin tolerance and GH-RH tests, and had episodic LH secretion with higher frequency compared to the ovulated group. These results suggest that the desensitized women had occult pituitary dysfunction and hypersecretion of endogenous LH-RH which stimulated the pituitary close to the level of desensitization. The mechanism of hypersecretion of endogenous LH-RH is discussed.

Adult↗
PubMed1986

Small hepatocellular carcinomas in chronic liver disease: detection with SPECT.

Single-photon emission computed tomography (SPECT) performed using a rotating gamma camera was compared with alpha 1-fetoprotein (AFP) assay, conventional liver scintigraphy, ultrasound (US) imaging, computed tomography (CT), and selective celiac angiography in 40 patients with a total of 50 small hepatocellular carcinomas (HCCs; less than 5 cm). The detection rates of US and CT were determined on an initial screening study and on a second, more precisely focused study. The detection rate of small HCCs by the various modalities was as follows: AFP, 13%; liver scintigraphy, 36%; SPECT, 72%; initial screening US, 80%; second, more precise US studies, 94%; initial screening CT, 64%; second, more precise CT study, 82%; angiography, 88%. Although SPECT was inferior to the initial screening US examination in detecting HCCs less than 2 cm in size, its sensitivity was identical to that of the initial screening US study for detecting HCCs of 2-5 cm. The combination of SPECT and US was an excellent method for the early detection of HCCs, yielding a detection rate of 94%.

Aged↗
PubMed1986

[Subcutaneous long-term pulsatile administration of LH-RH to patients with hypothalamic amenorrhea].

The effects of pulsatile LH-RH administration on ovulation induction and luteal phase activity were studied in 8 women with hypothalamic amenorrhea (2, with primary amenorrhea and 6 with secondary). Ten to 20 micrograms of LH-RH was subcutaneously injected by autoinfusion pump every 2 hours for more than 56 days. Six out of 8 women responded to the treatment and showed a total of 18 ovulatory cycles. The mean length of the follicular and luteal phases was 25.9 +/- 6.37 days and 11.9 +/- 0.43 days, respectively. The serum progesterone level in mid luteal phase was 12.0 +/- 2.35 ng/ml and was in the normal range for naturally cycling women. Two patients with secondary amenorrhea conceived in the 2nd and 3rd ovulatory cycle, respectively. In two patients who showed no response to LH-RH pulsatile administration for 56 days of treatment, serum LH and FSH levels were gradually lowered and the response to 100 micrograms of LH-RH iv injection was remarkably attenuated, suggesting that the pituitary gland was desensitized by the treatment.

Adult↗
PubMed1986

Concept of the clinical stages of acute hepatic failure.

Serial medical diagnostic imagings were performed on 15 patients with acute hepatic failure to compare liver size and clinical picture. In patients showing hepatatrophy at the onset of coma, the interval between the onsets of disease and coma was long, ascites and edema supervened, high total bilirubin and low glutamic pyrubic transaminase levels tended to be found, and prothrombin time did not respond to treatment. All of these patients died. Based on liver size changes in patients who survived acute hepatic failure, acute hepatic failure was assumed to be classified into swelling, reduction, and recovery stages. The shorter the interval between the onsets of disease and coma, the earlier coma and prolonged prothrombin time occurred before hepatatrophy. In acute hepatic failure, signs of hepatic failure develop with various histological pictures and it is very important to institute the treatment before the liver is atrophied.

Acute Disease↗
PubMed1985

[Studies on specific receptors for prolactin (PRL) in the rat ovary].

The characteristics of specific receptors for prolactin (PRL) in the ovary were examined. The binding of 125I-ovine PRL to the receptor was dependent upon time, temperature, and tissue concentration. Equilibrium was reached by 16 h at 23 degrees C in the 12.5 mg tissue/tube. Scatchard analysis revealed a high affinity, low capacity and single class of binding site. Ovine PRL bound to rat liver membranes with a Kd (dissociation constant) of 3.51 X 10(-10) M and to rat ovarian membranes with a Kd of 2.21 X 10(-10) M, respectively. The number of binding sites in rat liver and ovary were 205.2 fmoles/mg of protein and 226.1 fmoles/mg of protein, respectively. Bound 125I-ovine PRL was displaceable by unlabelled human, ovine and rat PRL but not by rat LH, FSH, TSH or GH. However, on the immunological aspects, 125I-ovine PRL bound only to anti-ovine PRL serum but did not bind to anti-human PRL serum or anti-rat PRL serum. Unlabelled human and rat PRL could not inhibit the binding of labelled ovine PRL to the anti-ovine PRL serum. These data indicate the existence of specific PRL receptors in the rat ovary, the characteristics of which are similar to those of receptors in the liver. The binding specificity for various mammalian species suggests a difference between biological and immunological binding sites of the PRL molecule.

Animals↗
PubMed1985

[The ionic heterogeneity of human prolactin (PRL) from amniotic fluid].

The ionic heterogeneity of prolactin (PRL) secreted in the human amniotic fluid was investigated using new precise chemical techniques. From five liters of amniotic fluid, the PRL fractions were purified with 70% ammonium sulfate precipitation, ethanol fractionation, desalting by gel filtration on Sephadex G-25, and ion-exchange chromatography using Mono Q on Fast Protein Liquid Chromatography (FPLC). The last FPLC was repeated until homogeneous preparations were obtained. Hormonal activity of each fraction was determined with a NIADDK radioimmunoassay (RIA) kit for human PRL. The PRL activity of the finally-purified component was also assayed by radioreceptor analysis (RRA) using rat liver cell membranes as the receptor. From the amniotic fluid, seven components of the PRL were eluted at NaCl concentrations from 0.065M to 0.13M in 0.02M Tris-HCl, pH 8.0. The RRA/RIA values of these seven components were different from each other (from 0.32 to 0.97). The lower the NaCl concentrations, the higher the RRA/RIA values were. The molecular weight of each component determined by gel filtration on TSK-SW 3000 with HPLC, was similar (MW 23,000) corresponding to "small-PRL".

Amniotic Fluid↗
PubMed1979

[Sphenoethmoidal meningoencephalocele associated with agenesis of corpus callosum and median cleft lip and palate--report of two cases (author's transl)].

Two cases of sphenoethmoidal meningoencephalocele are reported. Patients are a 1 year 7 month old boy and a 3 year old boy. Although sphenoethmoidal meningoencephalocele is reasonably classified as a type of basal meningoencephalocele, the authors could not find out any reports on cases designated as such. The reason must be in difficulty to differentiate the sphenoethmoidal type from the transsphenoidal type. Authors could differentiate them using CT scan. Two other cases were found in cases reported as transsphenoidal type. Further, it is assumed that these four cases including our two cases were accompanied with agenesis of corpus callosum and median cleft lip and palate. Despite the fact that the respective anomalies are rare, they are completely the same, which signifies the possibility that 1) sphenoethmoidal meningoencephalocele, 2) agenesis of corpus callosum and 3) median cleft lip and palate are a single unit of congenital anomalies. It probably should be considered that the cause for these malformations were present even before the formation of the lips which takes place earliest, that is, sixth week of gestation.

Abnormalities, Multiple↗