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C Azuma

Publications and source records attributed to C Azuma.

At least 55 records · Page 3Linked to original sources
PubMed1996

The novel role of 3',5'-guanosine monophosphate (cGMP) on the differentiation of trophoblasts: comparison with the effects of 3',5'-adenosine monophosphate (cAMP).

We investigated the effects of 3',5'-guanosine monophosphate (cGMP) on the differentiation of human trophoblasts. Isolated cytotrophoblasts were cultured with 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) or 8-bromoadenosine 3'5-cyclic monophosphate (8-Br-cAMP) and then stained immunocytochemically with anti-human chorionic gonadotropin (anti-hCG) antibody to identify hCG expression as an index of differentiation. Concurrently, morphological changes from cytotrophoblasts to syncytiotrophoblasts were analyzed. Both 8-Br-cGMP and 8-Br-cAMP enhanced the expression of hCG in cultured cytotrophoblasts with the differentiation of cytotrophoblasts to syncytiotrophoblasts dose-dependently. With regard to trophoblast proliferation, 8-Br-cAMP but not 8-Br-cGMP enhanced [3H]thymidine uptake by these cells. hCG, a trophoblast-specific glycoprotein hormone has been identified as a potent growth factor for trophoblasts, also increased [3H]thymidine uptake and the intracellular 3',5'-adenosine monophosphate (cAMP) concentration. However, in this study, hCG did not increase the concentration of intracellular cGMP. We also showed that sodium nitroprusside (SNP), which is a donor of nitric oxide (NO), enhanced intracellular cGMP concentration. These results suggest that cGMP enhances trophoblast differentiation without affecting their proliferation, while cAMP enhances both differentiation and proliferation. We conclude that an alternative pathway mediated through cGMP is responsible for the differentiation of trophoblasts. NO may be involved in trophoblast differentiation with an increase in cellular cGMP level.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1995

Leukemia inhibitory factor (LIF) enhances trophoblast differentiation mediated by human chorionic gonadotropin (hCG).

We investigated the effect of LIF on the differentiation of trophoblasts. Isolated cytotrophoblasts were cultured with and without LIF and cell smears were immunocytochemically analyzed, using anti-hCG antibody. The percentage of differentiated trophoblasts stimulated by 10ng/ml of LIF was about 2.5-fold that in the control culture. The effect of LIF in inducing the differentiation of cytotrophoblasts to syncytiotrophoblasts was dose-dependent. The same effect was shown when hCG was added to the medium. This enhancing effect of LIF on trophoblast differentiation was blocked by adding anti-hCG antibody to the culture system. These results indicate that LIF enhanced trophoblast differentiation by stimulating hCG production in trophoblasts, and not by exerting a direct effect on the trophoblasts.

Abortion, Legal↗
PubMed1995

Detection of c-erbB-2 gene amplification in nipple discharge by means of polymerase chain reaction.

In a patient with non-palpable breast carcinoma, c-erbB-2 gene amplification was detected by means of polymerase chain reaction (PCR) in the small number of breast carcinoma cells present in nipple discharge. Amplification of the c-erbB-2 gene is more frequent in carcinoma in situ than in invasive types. Detection by a PCR-based method may help diagnose non-palpable breast carcinoma with nipple discharge. Since this gene amplification is related to high proliferation, it might provide useful preoperative information regarding intraductal carcinoma of comedo type and predict responses to chemotherapy.

Adult↗
PubMed1995

Interleukin-1 receptor antagonist expression in epithelial cells of human endometrium.

OBJECTIVE: To examine the expression of interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra) in the human endometrium in the follicular and luteal phases. METHODS: The concentrations of IL-1alpha and IL-1beta in the culture supernatants of endometrial cells were determined by enzyme-linked immunosorbent assay. Transcription of the IL-1ra gene in the endometrium was investigated by reverse polymerase chain reaction (PCR). Human endometrium was immunohistochemically stained using a monoclonal antibody specific to IL-1ra. RESULTS: The concentrations of IL-1alpha and IL-1beta in the culture supernatants were 11 and 55 pg/ml, respectively, in the follicular phase, and 10 and 40 pg/ml, respectively, in the luteal phase. The concentration of IL-1ra was 465 pg/ml in the follicular phase and 1710 pg/ml in the luteal phase. Densitometric analysis of the reverse PCR products showed that the expression of IL-1ra mRNA was increased in endometrial cells in the luteal phase. Immunohistochemical staining revealed that epithelial cells were the main source of IL-1ra in human endometrium. CONCLUSIONS: Human endometrial cells produce IL-1 (mainly IL-1beta) and IL-1ra. The level of IL-1ra production in human endometrial epithelial cells was greater in the luteal phase than in the follicular phase due to the increased transcription of the IL-1ra gene.

Endometrium↗
PubMed1995

Clonal determination of uterine leiomyomas by analyzing differential inactivation of the X-chromosome-linked phosphoglycerokinase gene.

To investigate the clonality of uterine leiomyomas, we developed a PCR-based method involving the differential inactivation of the X-chromosome-linked phosphoglycerokinase (PGK) gene. Small DNA samples of 22 leiomyomas from 9 Japanese patients, showing heterozygosity at the BstXI site of the PGK gene, were digested with the methylation-sensitive restriction enzyme HpaII. Only the inactive (methylated) PGK gene allele was selectively amplified by PCR followed by digestion with BstXI and electrophoresis. All leiomyoma samples consisted of a single type of inactive allele, even though alleles were detected that were specific to each nodule. The results indicated that all leiomyoma nodules were unicellular in origin but independently generated in the uterus.

Adult↗
PubMed1994

Structural organization of the human oxytocin receptor gene.

We isolated and characterized the human oxytocin receptor gene. Southern blots indicated that the human genome has a single copy of the gene. Chromosomal localization by fluorescence in situ hybridization also showed that the gene was a single copy, assigned to 3p26.2 of the human chromosome. The gene spans approximately 17 kilobases and contains 3 introns and 4 exons. Exons 1 and 2 correspond to the 5'-non-coding region, followed by exons 3 and 4 encoding the amino acids of the receptor. Intron 3, which is the largest at 12 kilobases, separates the coding region immediately after the putative sixth transmembrane-spanning domain. The transcription start sites, demonstrated by primer extension analysis, lie 618 and 621 base pairs upstream of the methionine initiation codon. Near these putative transcription start sites, we found a TATA-like motif and a potential SP-1 binding site at about 30 and 65 base pairs, respectively. We also found other known binding sites of transcription regulating factors, such as AP-1, AP-2, GATA-1, Myb, nucleofactor-interleukin 6 binding consensus sequence, and an acute phase reactant-responsive element. No estrogen-responsive element was observed except three half-palindromic estrogen-responsive element motifs. Our findings of the oxytocin receptor gene structure should help to elucidate the mechanism by which the gene expression is induced drastically at parturition in the uterus and how the gene is regulated in other organs such as the mammary gland or central nervous system.

Amino Acid Sequence↗
PubMed1994

Lupus anticoagulant autoantibody induces apoptosis in umbilical vein endothelial cells: involvement of annexin V.

The effects of lupus anticoagulant (LAC) on cultured human umbilical vein endothelial cells were studied. All five monoclonal antibodies from a patient with systemic lupus erythematosus (SLE), as well as plasma samples with LAC activity from six SLE patients, induced apoptosis. Anti-annexin V IgG also induced apoptosis. Since monoclonal antibodies and plasma from SLE patients had an affinity for annexin V, an endothelial apoptosis pathway mediated by annexin V was suggested as the molecular pathogenesis of the hemostatic derangement associated with LAC.

Animals↗
PubMed1994

Heterogeneity and diversity of IgM and IgG lupus anticoagulants in an individual with systemic lupus erythematosus.

From one patient with systemic lupus erythematosus retaining lupus anticoagulant (LAC), we established 6 Epstein-Barr virus-transformed human B cell clones secreting antibodies that affect the coagulation assay. Two and 4 of the clones secreted IgM and IgG antibodies, respectively. Although all 6 antibodies displayed anticardiolipin activity in ELISA, the increased binding activity in the presence of beta 2-glycoprotein I was limited only to the IgG antibodies. Five antibodies (two IgM and three IgG) had LAC activity which prolonged the activated partial thromboplastin time (APTT), whereas one IgG antibody shortened the APTT. Two of the IgG producing clones had an identical Ig heavy chain gene rearrangement despite their opposite effects on the coagulation assay. These results demonstrated the heterogeneity of LACs and diversity among their physiological functions.

Adult↗
PubMed1994

Clonal analysis of human gynecologic cancers by means of the polymerase chain reaction.

Clonality of human gynecologic cancers was analyzed in small DNA samples prepared from cryostat sections, by means of the polymerase chain reaction (PCR). The method used for clonal analysis was based on restriction fragment length polymorphism of the X-chromosome-linked phosphoglycerokinase (PGK) gene and on the differential methylation of the PGK gene due to random inactivation of 1 of 2 X-chromosomes by methylation in females. Among 52 gynecologic cancers tested, 25 were found to be heterozygous for the BstXI polymorphism of the PGK gene. All the 25 gynecologic cancers (4 cervix, 11 endometrium, 7 ovary and 3 fallopian tube) analyzed by the PCR-based method were monoclonal in origin while adjacent normal tissues were polyclonal. When DNA samples were prepared from widely separated sites of tumors and/or metastatic lesions, every sample was found to be monoclonal, and the same allele of the PGK gene was inactivated in each case. These results demonstrate that clonal analysis by PCR offers a good method for studying clonality in small DNA samples prepared from cryostat sections of tumors. This method could be applied to distinguish between benign and malignant gynecologic lesions.

Adult↗
PubMed1994

Type-IV collagenase and tissue inhibitor of metalloproteinase in ovarian cancer tissues.

OBJECTIVE: We examined the specific expression of gelatinase/type-IV collagenase and tissue inhibitor of metalloproteinase (TIMP) in clinical ovarian cancer tissue. METHODS: Molecular weight-specific gelatinase/type-IV collagenase activity was examined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis in which substrate was included (zymography). The expression of TIMP mRNA was examined by Northern blot analysis. RESULTS: Zymography revealed that in ovarian cancer the activity of a 92-kDa gelatinase/type-IV collagenase was always greater than that of a 64-kDa gelatinase/type-IV collagenase in contrast to the situation in the normal ovary. Northern blot analysis revealed no remarkable difference of TIMP mRNA expression between cancer and normal ovarian tissues. CONCLUSIONS: These results indicate that the higher activity of the 92-kDa gelatinase/type-IV collagenase enzyme, relative to that of the 64-kDa enzyme, is involved in the malignant phenotype of ovarian cancer, while the inhibitor of these enzymes, TIMP, is distributed in a widespread fashion in the tissue, and its levels are not correlated with the malignancy.

Adenocarcinoma, Clear Cell↗
PubMed1994

Loss of biological activity of human chorionic gonadotropin (hCG) by the amino acid substitution on the "CMGCC" region of the alpha-subunit.

In order to study the bioactive sites of the glycoprotein hormones, we have prepared five point mutants on the CMGCC (Cys28-Met29-Gly30-Cys31-Cys32) region of the human alpha-subunit by using site-directed mutagenesis. Each mutant human chorionic gonadotropin (hCG) agr; cDNA and a wild-type hCG beta cDNA were transcribed by T3 RNA polymerase, and the mixture of the hCG alpha mRNA and hCG beta mRNA was microinjected into Xenopus laevis oocytes. All five mutant hCGs produced in oocyte culture supernatants were detected as immunoreactive forms by enzyme immunoassay. In contrast, four mutants (Cys28-->Tyr28, Gly30-->Arg30, Ala30, Asp30) were devoid of biological activity in vitro bioassay using the production of testosterone with mouse Leydig cells. These results indicate that the CMGCC region in the alpha-subunit, particularly the cysteine residue at position 28 and the glycine residue at position 30, plays an important role in the biosynthesis of glycoprotein hormones.

Amino Acid Sequence↗
PubMed1994

A case of quadruplet pregnancy containing complete mole and three fetuses.

A case of a quadruplet pregnancy containing a complete mole and three fetuses is reported. A 29-year-old Japanese woman who had received clomiphene therapy was delivered of a complete mole, one dead and two living fetuses, and three placentas. Deoxyribonucleic acid fingerprint analysis proved the androgenesis of molar tissue and the trizygosity of the three fetuses.

Adult↗
PubMed1994

Molecular characterization of a cloned human oxytocin receptor.

We describe here the binding and functional properties of a cloned human oxytocin receptor (OTR). We established a transient OTR expression system on COS-1 cells, which do not express vasopressin receptors. With the transfected cells and [3H]oxytocin, the dissociation constant (Kd) of OTR to oxytocin was 6.0 +/- 1.1 nmol/l; the binding properties of several oxytocin-related peptides were also examined. The functional properties of OTR were determined by an electrophysiological method, using a Xenopus laevis oocyte injected with in vitro transcribed OTR mRNA. These two methods showed that [Phe2,Orn8]vasotocin, a vasopressin agonist, was an OTR antagonist. A combination of these methods using cloned OTR cDNA is a novel and effective method for the investigation of oxytocin-related ligands.

Animals↗