Search PubMed⌕ Search

Biomedical subjects

T Aso

Publications and source records attributed to T Aso.

At least 163 records · Page 9Linked to original sources
PubMed1993

Protein kinase C activation and calcium mobilization decrease prolactin release from human decidual cells in early pregnancy.

The present study was undertaken to investigate the effects of protein kinase C (PKC) activation and calcium mobilization on the release of prolactin from human decidual cells in early pregnancy. Decidua obtained from patients in early pregnancy was enzymatically dispersed and cultured with phorbol myristate acetate (PMA) and calcium ionophore A23187 in a cell culture system. Prolactin in the medium was measured by enzyme-immunoassay. PMA, a PKC activator, dose-dependently attenuated the release of prolactin from cultured decidual cells, while a PKC inhibitor, H7, significantly (P < 0.001) diminished the effect of PMA on prolactin release. PMA had no effect on cell numbers or DNA synthesis in the decidual cells during culture. It did not significantly increase the generation of inositol phosphate in decidual cells prelabelled with myo-[3H]inositol and it had no effect on intracellular calcium concentration ([Ca2+]i). Calcium ionophore A23187, a Ca(2+)-mobilizing agent, also significantly (P < 0.001) attenuated the release of prolactin and potentiated the PMA-induced suppression of prolactin release from decidual cells. These findings suggest that activation of PKC and mobilization of Ca2+ may be involved in regulating prolactin release from human decidual cells. The PMA-induced suppression of prolactin release is not triggered by phosphoinositide hydrolysis nor by the increase in [Ca2+]i in decidual cells.

Calcimycin↗
PubMed1992

Fluorometric assay of 25-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 in plasma.

The first practical fluorometric assay of plasma 25-hydroxyvitamin D3 (25-OH-D3) and 24R,25-dihydroxyvitamin D3 (24,25-(OH)2D3) is described. The method uses a highly fluorescent dienophile, 4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyl]-1, 2,4- triazoline-3,5-dione (DMEQ-TAD), to fluorescence-label vitamin D. Vitamin D metabolites were roughly purified with a short cartridge column followed by HPLC, labeled with DMEQ-TAD, and the product was analyzed on HPLC. In the assay of 25-OH-D3 the new fluorometric method was compared with the HPLC-uv method and was confirmed to be as accurate and reliable (CV, 4-5%) as the HPLC-uv method. Plasma 24,25-(OH)2D3 was accurately assayed by the HPLC-FL method, where the standard addition method was successfully used to calculate the overall recovery.

24,25-Dihydroxyvitamin D 3↗
PubMed1992

Characterization of cDNA for the large subunit of the transcription initiation factor TFIIF.

At least six chromatographically resolvable general transcription factors may participate in accurate initiation by RNA polymerase II in HeLa cell-derived systems. TFIIF (also termed FC, RAP30/74 and beta/gamma) can bind directly to RNA polymerase II in solution and decrease the affinity of RNA polymerase II for nonspecific DNA. From studies on the kinetics of transcription initiation, on the composition of transcription initiation complexes fractionated by acrylamide gel electrophoresis, and on template competition experiments, TFIIF is known to act at an intermediate stage in initiation complex formation. It acts after TFIID firmly associates with DNA, but coincidentally with or immediately after RNA polymerase II binding to DNA, and before the recruitment of factor TFIIE. TFIIF may or may not have DNA helicase activity. The small subunit (RAP30) of TFIIF has been cloned and shows some amino-acid sequence homology to bacterial sigma factors. We have partially sequenced the RAP74 protein from purified HeLa cells, cloned its complementary DNA and shown that its translation product can interact with RAP30 in vitro as well as in vivo. The cDNA predicts an amino-acid sequence that lacks obvious DNA or RNA helicase motifs. It has regions rich in charged amino acids, including segments containing a higher content of acidic amino acids than are found in strong transcriptional activators such as VP16.

Amino Acid Sequence↗
PubMed1992

Clinical gynecologic features of pregnancy in Takayasu arteritis.

Takayasu arteritis is a non-specific chronic inflammatory vascular disease of unknown etiology. Since the incidence of this disease in the child-bearing years is relatively high, the management of pregnancies with this disease is of great importance in clinical obstetrics. This study is aimed at discussing the maternal management and obstetrical outcome, based on the clinical data obtained from 23 pregnancies of 15 patients treated in our hospital in the past 12 years. Since the disease was in the active state, artificial abortions were conducted in four cases in the 1st trimester of pregnancy. Among the remaining 16 cases, 3, who exhibited neither hypertension nor other complications, vaginally delivered neonates weighing 2,660-3,100 g with Apgar scores of nine after 37 weeks' gestation. C-sections were performed for 13 patients who showed sustained hypertension or/and developed other vascular disorders. Their gestational periods ranged from 34 to 40 weeks and the body weight of the infants varied from 1,425 to 3,024 g. No adverse influence of pregnancy and delivery on Takayasu arteritis was detected in the puerperium of any patients. It is suggested that the state of Takayasu arteritis in early pregnancy and the magnitude of blood pressure elevation in the late gestational period are the most critical and definitive factors in determining the management of pregnancy of a patient with Takayasu arteritis. Cooperative managements by the specialists in obstetrics, internal medicine, and perinatology are required to provide a satisfactory clinical outcome.

Abortion, Induced↗
PubMed1992

Effects of insulin-like growth factor-II on proliferation and differentiation of ovarian granulosa cells.

The effects of insulin-like growth factor-II (IGF-II) on the proliferation and differentiation of ovarian granulosa cells were studied in cultured human and porcine granulosa cells. IGF-II significantly increased basal progesterone secretion in granulosa cells at concentrations of 1-100 ng/ml. A stimulatory effect was also observed in gonadotropin-stimulated porcine granulosa cells treated with IGF-II. The secretion of estradiol by basal and gonadotropin-stimulated porcine granulosa cells was also significantly increased by adding IGF-II. IGF-II led to dose-dependent increases in [3H]thymidine incorporation into DNA and in the number of granulosa cells. To further characterize the cellular mechanisms underlying the stimulatory effects of IGF-II on the proliferation and differentiation of granulosa cells, we investigated the intermediary roles of cyclic AMP and intracellular Ca2+ concentration ([Ca2+]i). Treatment with 100 ng/ml IGF-II produced a significant increase in the basal accumulation of cyclic AMP in porcine granulosa cells. However, no change of [Ca2+]i by IGF-II was noted. IGF-II produced effects in accumulation that were similar to those of IGF-I. Our findings suggest that IGF-II may be a general stimulator in the proliferation and differentiation of granulosa cells, and that cyclic AMP may be a second messenger for the effects of IGF-II in ovarian granulosa cells.

Animals↗
PubMed1992

Influence of progesterone/estradiol ratio on luteal function for achieving pregnancy in gonadotropin therapy.

The purpose of this study was to evaluate the influence of the relationship between plasma progesterone (P4) and estradiol (E2) levels in the luteal phase for achieving pregnancy in human menopausal gonadotropin (hMG)-human chorionic gonadotropin (hCG)-treated cycles. Plasma P4 and E2 levels were determined in 93 hMG-hCG-treated cycles (23 pregnant and 70 nonpregnant) of 46 patients during 3 periods of the luteal phase, using radioimmunoassay. In addition, 88 spontaneous ovulatory cycles and 100 clomiphene-treated cycles were also studied in the same manner. In hMG-hCG-treated cycles in the early luteal phase, the P4/E2 ratio in pregnant cycles was significantly higher than that in nonpregnant cycles. There was no significant difference between the P4/E2 ratios of the luteal phase of hMG-hCG-treated pregnant-group, clomiphene-treated and spontaneous ovulatory cycles. In nonpregnant cycles, however, the P4/E2 ratio in hMG-hCG-treated cycles was significantly lower than that in clomiphene-treated or spontaneous ovulatory cycles. These results suggest that in hMG-hCG-treated cycles, the P4/E2 ratio may be a more reliable index of luteal function for achieving pregnancy than P4 levels alone.

Chorionic Gonadotropin↗
PubMed1992

Synthesis and release of endothelin-1 by human decidual cells.

We have studied whether a novel vasoconstrictor, endothelin-1 (ET-1), is synthesized by and released from human decidual cells in early pregnancy, and whether ET-1 acts directly on their own cells. It was observed that ET-1-like immunoreactivity (ET-1-LI) was released from cultured decidual, but not villous, cells, as a function of time. Reverse-phase high-pressure liquid chromatography of the conditioned media from the decidual cells revealed a major peak of ET-1-LI coeluting with standard ET-1. Phorbol myristate acetate, a protein kinase C activator, dose-dependently increased the release of ET-1-LI from the decidual cells, while a protein kinase C inhibitor, H7, significantly attenuated the stimulatory effect of phorbol myristate acetate on ET-1-LI release. Northern blot analysis demonstrated the expression of messenger RNA for prepro-ET-1 in the decidual tissue, but no such messenger RNA was observed in the villous tissue. The human decidual tissue contained a noninteracting, single class of binding sites demonstrating higher affinity for ET-1 and ET-2 than ET-3. This would be most consistent with the ETA receptor subtype. An ET-1-induced, dose-dependent accumulation of total inositol phosphates was also observed in human decidual cells prelabeled with myo-[3H]inositol. The present results demonstrate for the first time that human decidual cells in early pregnancy can synthesize and release ET-1. These cells also possess specific functional receptors for ET-1 which are coupled to phosphoinositide hydrolysis. Thus our data suggest a possible role for ET-1 in autocrine and/or paracrine function in human decidual cells.

Binding, Competitive↗
PubMed1992

Usefulness and limitation of measurement of insulin-like growth factor binding protein-3 (IGFBP-3) for diagnosis of growth hormone deficiency.

To analyze the utility of insulin-like growth factor binding protein-3 (IGFBP-3) radioimmunoassay for diagnosis of growth hormone deficiency (GHD) we measured IGFBP-3 in sera from normal children, short children and patients with GHD. The sensitivity (true positive ratio) of IGFBP-3 for complete GHD (cGHD) was 93%, while the specificity (true negative ratio) for normal short children (NS) was 88%. In contrast, the sensitivity of IGFBP-3 for partial GHD (pGHD) was only 43%. The poor discrimination between patients with pGHD and NS may be the result of their relatively similar GH level, as compared to cGHD, or due to the limitations of GH stimulation tests. The specificity of IGFBP-3 for NS was excellent in children of all ages: less than 10 years old (87%) and older than 10 (88%). However, sensitivity for GHD was good for children less than 10 years old (84%) but poor for children older than 10 (64%). IGFBP-3 may be less sensitive for diagnosing GHD in older children because IGFBP-3 levels may also increase during puberty due to mechanisms independent of the GH-IGF-I axis.

Adolescent↗
PubMed1992

Direct effects of bromocriptine on the steroidogenic capability of porcine granulosa cells.

The direct effects of bromocriptine on steroidogenesis were examined in cultured porcine granulosa cells. The following observations were made with bromocriptine: (1) It significantly increased the basal or FSH-stimulated secretion of progesterone in cultured porcine granulosa cells at concentrations exceeding 10(-7) mol/l; (2) its inhibitory effect on basal estradiol secretion was demonstrated; (3) it did not influence cell number in cultured porcine granulosa cells; (4) it increased the extracellular accumulation of cAMP in a concentration-dependent manner; and (5) it did not induce a change in cytosolic free Ca2+ concentration. These findings suggest that bromocriptine exerts a direct effect on steroidogenesis in ovarian granulosa cells.

Animals↗
PubMed1992

Determination of insulin-like growth factor-2 in feto-maternal circulation during human pregnancy.

In order to clarify the roles of insulin-like growth factors (IGFs) on the human maternal-fetal environment, IGF-2 and IGF-1 levels were investigated in human plasma and amniotic fluid during pregnancy. Initially, new radio-immunoassay (RIA) systems for human IGF-2 could be developed. The sensitivity of this assay was 17.5 pg/tube and the cross-reactivity with IGF-1 was 0.64%. The pattern of change of maternal plasma IGF-2 in early pregnancy differed from that of IGF-1, but both IGF levels increased progressively in the second half of gestation, and decreased to non-pregnancy levels in the puerperium. Maternal levels of IGF-2 were approximately seven times greater than those of IGF-1. The ratio of IGF-2 to IGF-1 was 3.2 in amniotic fluid. The IGF concentrations in amniotic fluid obtained in the second trimester were significantly greater than those of term specimens, and closely related to those of prolactin (PRL) in amniotic fluid. The highest IGF-2 to IGF-1 ratio (15.9) was found in umbilical vein plasma. On Sephadex G-150 gel-chromatography of maternal and fetal plasma at term, two apparent peaks of unsaturated IGF-2 binding protein (BP) could be detected in both 150 and 40 kilo dalton (kD) regions. One main peak of unsaturated IGF-2 BP could be determined in the 40 kD region in the amniotic fluid at term. High concentration of IGF-2 could be detected in feto-maternal circulation during human pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1992

Direct effect of endothelin-1 on the granuloma cells of the porcine ovary.

Specific binding sites for endothelin-1 (ET-1), a novel potent vasoconstrictor peptide, as well as the effects of ET-1 on cytosolic free Ca2+ concentration ([Ca2+]i), intracellular total inositol phosphate (IP) generation and steroidogenesis were studied in cultured porcine granulosa cells. Scatchard analysis of a binding study using 125I-labelled ET-1 indicated the presence of a single class of high-affinity binding sites with almost equal affinity for ET-1 and ET-3: the apparent dissociation constant was 0.59 nmol/l and the maximal binding capacity was 1.84 pmol/mg protein. Affinity-labelling of 125I-labelled ET-1 to the membranes using disuccinimidyl tartarate as a cross-linker revealed one major and one minor band with the apparent molecular weights of 32 kDa and 49 kDa respectively. ET-1 dose-dependently (1-100 nmol/l) induced rapid and transient increases in [Ca2+]i in fura-2-labelled cells. ET-1 also dose-dependently stimulated total IPs in cells prelabelled with myo-[3H]inositol. ET-1 had a slight stimulatory effect on the secretion of progesterone but not of oestradiol from porcine granulosa cells. The present data clearly demonstrate the presence of a non-selective ET receptor (ETB) in porcine granulosa cells coupled with phosphoinositide hydrolysis and [Ca2+]i mobilization, and suggest that ET-1 may play some role in the production of progesterone by porcine granulosa cells.

Animals↗
PubMed1991

Genomic organization of the alpha chain of the human C4b-binding protein gene.

C4b-binding protein (C4bp) is a serum glycoprotein that is one of the regulators of the complement activation (RCA) family. This protein is composed of structurally related 70-kDa (alpha chain) and 45-kDa (beta chain) polypeptides. The alpha chain of C4bp (C4bp alpha) consists of eight short consensus repeats (SCR), which constitute the amino-terminal 491 residues. Human C4bp is also one of the acute-phase reactants. In order to clarify the genetic basis of the SCR and to understand the regulatory mechanisms of C4bp synthesis, we isolated 6 genomic DNA clones covering all of the human C4bp alpha gene. This gene consists of 12 exons and spans about 40 kb. Each of the SCRs is encoded by a single exon, except for the second SCR (SCR II), which is encoded by two separate exons, demonstrating that human C4bp alpha has a split SCR at the genomic level. The 5' flanking region was sequenced up to 380 bases upstream from the putative transcription initiation site. Several possible binding sites for transcription factors were identified.

Base Sequence↗
PubMed1991

Role of angiotensin on paracrine prolactin release in the pituitary gland and its possible effects on ovarian function.

The present study was undertaken to investigate the role of angiotensin II (AII) in GnRH-induced PRL release on the paracrine interaction among anterior pituitary cells of young male rats. A 20-min perifusion with 100 nM GnRH increased PRL release (p less than 0.01) from pituitary cell aggregates, and GnRH-stimulated release of PRL was significantly suppressed by saralasin, a specific AII antagonist. The release of AI from pituitary cell aggregates was significantly (p less than 0.01) increased by GnRH. These data demonstrate that GnRH is capable of stimulating PRL release through a mechanism that may involve the release of angiotensin. It was also speculated that some factors released from pituitary cells, such as angiotensin, might be involved in the control of ovarian functions. As an approach to investigate this possibility, porcine anterior pituitary cells and ovarian granulosa cells were co-cultured on type 1 collagen membrane which permits the exchange of the substance with molecular weights less than 9,000. The growth and progesterone production of the granulosa cells co-cultured with pituitary cells were significantly (p less than 0.05) greater than those of the cells cultured in monolayer fashion. Thus, the results of the present study revealed the biological significances of the paracrine system involving angiotensin between gonadotroph and lactotroph in pituitary cells and the direct effect of the factors derived from pituitary cells on ovarian functions.

Angiotensin I↗
PubMed1991

Interleukin 6 and tumor necrosis factor fully activate liver-specific gene expression of the alpha chain of C4b-binding protein.

We investigated the gene expression of the alpha chain of C4b-binding protein (C4bp alpha) in a variety of tissues, and in liver cell and hepatoma lines. C4bp alpha mRNA was detected in the liver, but not in the other tissues examined. The constitutive gene expression of C4bp alpha by a hepatoma line, HepG2, was significantly augmented by treatment with monocyte-conditioned medium (MoCM), 12-O-tetradecanoylphorbol-13-acetate (TPA), interleukin-6 (IL6) and tumor necrosis factor (TNF) but not by a calcium ionophore (A23187) or interleukin-1 beta (IL1 beta).

Blotting, Northern↗
PubMed1991

[The effects of insulin-like growth factor-I (IGF-I) and IGF-II on prolactin (PRL) release from human decidua and amniotic fluid circulation].

It has been reported that insulin-like growth factor (IGF) may play an important role in the feto-placental environment during pregnancy. The present study was undertaken to investigate the effect of IGF-I and IGF-II on prolactin (PRL) release from human decidual cells in vitro and in vivo. The human decidua in early pregnancy was obtained by D & C, and was enzymatically dispersed into a monocellular suspension. Monolayer cultures of these cells were exposed for 96 hours to either control media or medium supplemented with IGF-I and IGF-II. PRL levels in the media were measured by EIA. Five days after dispersion, the intracellular calcium concentration [( Ca]2+i) in cultured decidual cells was measured by the Fura-2 fluorescence method with a Spectrofluorometer. PRL and IGF-I levels in amniotic fluid of 2nd trimester and term pregnancy were measured by RIA for in vivo study. In an in vitro study, IGF-I increased PRL release from decidual cells significantly during a 96 hour culture. However, IGF-II did not enhance this PRL release. IGF-I stimulation had no effect on [Ca]2+i. In an in vivo study, amniotic fluid IGF-I levels in the 2nd trimester (139.8 +/- 28.1 ng/ml) were significantly higher than those in term pregnancy (46.4 +/- 14.2 ng/ml), and a significant positive correlation (r = 0.852, p less than 0.001) was observed between IGF-I and PRL levels in the amniotic fluid. The present in vivo and in vitro studies indicated that IGF-I plays an important role in PRL release from decidua into amniotic fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1991

[The role of angiotensin in paracrine interaction between rat anterior pituitary cells].

The present study was undertaken to investigate the role of angiotensin II (AII) in GnRH-induced prolactin (PRL) release from anterior pituitary cells of young male rats. The anterior pituitary glands were enzymatically dispersed, and subsequently the cells were allowed to reaggregate for 48 hours. Twenty-min perifusion with 100 nM GnRH increased PRL release (p less than 0.01) from the anterior pituitary cell aggregates. The integrated value for PRL release was 9.1 +/- 2.9 ng/10(7) cells. The release of angiotensin I (AI) from these perifused pituitary aggregates was significantly increased by GnRH. In contrast, GnRH-stimulated release of PRL was significantly suppressed by saralasin, a specific AII antagonist, whereas saralasin did not attenuate GnRH-induced LH release from these aggregates. These data demonstrate that GnRH is capable of stimulating PRL release through a mechanism that may involve the release of angiotensin.

Angiotensin II↗