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Dive into the research topics where Chihiro Azuma is active.

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Featured researches published by Chihiro Azuma.


Gynecologic and Obstetric Investigation | 1995

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

Kazumasa Hashimoto; Chihiro Azuma; Shoji Kamiura; Tadashi Kimura; Toshikatsu Nobunaga; T. Kanai; Masumi Sawada; Shinzaburo Noguchi; Fumitaka Saji

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.


Gynecologic and Obstetric Investigation | 1996

Plasma Nitric Oxide Levels in Pregnant Patients with Preeclampsia and Essential Hypertension

Toshikatsu Nobunaga; Yoshihiro Tokugawa; Kazumasa Hashimoto; Tadashi Kimura; Noboru Matsuzaki; Nitta Y; Fujita T; Kidoguchi Ki; Chihiro Azuma; Fumitaka Saji

Nitric oxide (NO) production may be an important causal factor in hypertensive disorders during pregnancy. The plasma concentrations of NO2-(+) NO3-, stable metabolites of NO, were measured in 70 nonpregnant women, 323 normotensive pregnant women, 23 pregnant patients with preeclampsia, and 7 pregnant patients with essential hypertension. The normotensive women had higher plasma concentrations (30.0 +/- 0.6 mumol/l) than nonpregnant women (18.3 +/- 1.0 mumol/l; p < 0.0001). The plasma concentrations in the patients with preeclampsia (45.6 +/- 2.3 mumol/l) were higher than in the normotensive women (30.3 +/- 1.0 mumol/l; p < 0.0001) and were correlated with the systolic blood pressure (r = 0.442; p < 0.05). However, pregnant patients with underlying essential hypertension had significantly lower plasma concentrations (19.1 +/- 3.0 mumol/l; p < 0.005). These findings suggest that NO contributes to maternal vasodilation, the maintenance of uterine quiescence, and the pathogenesis and clinical features of hypertensive disorders during pregnancy.


American Journal of Reproductive Immunology | 1996

Elevated Nitric Oxide Concentration in the Seminal Plasma of Infertile Males: Nitric Oxide Inhibits Sperm Motility

Toshikatsu Nobunaga; Yoshihiro Tokugawa; Kazumasa Hashimoto; Yasue Kubota; Keisuke Sawai; Tadashi Kimura; Koichiro Shimoya; Masahiko Takemura; Noboru Matsuzaki; Chihiro Azuma; Fumitaka Saji

PROBLEM: To evaluate the “effect of nitric oxide in the seminal plasma on sperm motility. METHOD: Seminal plasma concentrations of NO2—, a stable end product of nitric oxide, of 108 males of infertile couples and 15 proven fertile donors were measured and compared with spermatogram parameters. Motile sperm was incubated with a nitric oxide‐generating drug, sodium nitroprusside, for 6 hr in the absence or presence of oxyhemoglobin, an inhibitor of nitric oxide.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2002

Detection of oxidative stress in seminal plasma and fractionated sperm from subfertile male patients

Hitomi Nakamura; Tadashi Kimura; Atsuko Nakajima; Koichiro Shimoya; Masahiko Takemura; Kazumasa Hashimoto; Shigeyuki Isaka; Chihiro Azuma; Masayasu Koyama; Yuji Murata

OBJECTIVES Oxidative stress in the reproductive system is thought to affect the fertilizing ability of sperm. Since 8-hydroxydeoxyguanosine (8-OHdG) and lipid peroxides are widely used as markers to quantify oxidative stress, we compared 8-OHdG and lipid peroxide concentrations in seminal plasma and spermatozoa from subfertile and fertile men. STUDY DESIGN Semen obtained from 37 men of subfertile couples (21 men with normozoospermia and 16 with asthenozoospermia) and from eight fertile volunteers were examined. Seminal plasma and spermatozoa were fractionated by four-step discontinuous Percoll gradient centrifugation. 8-OHdG in seminal plasma was measured by ELISA, and lipid peroxides in seminal plasma and spermatozoa were determined using a thiobarbituric acid (TBA) assay. RESULTS The concentrations of 8-OHdG and lipid peroxides in the seminal plasma of the subfertile group were significantly higher than those of the fertile group. There were no significant differences in these values between patients with normozoospermia and asthenozoospermia. In all four fractions obtained by Percoll gradient fractionation, the lipid peroxide levels in spermatozoa recovered from subfertile males were significantly higher than those of fertile controls. CONCLUSIONS Seminal plasma and spermatozoa from subfertile males showed elevated levels of oxidative stress that were detectable in ejaculated semen specimens by ELISA or TBA assay. Even the spermatozoa fraction considered to be mature and normal showed elevated oxidative stress in the subfertile group. Our results confirm the importance of oxidative stress in male reproductive function, and could be applied for the selection of patients for antioxidant therapy.


American Journal of Obstetrics and Gynecology | 1992

Triplet pregnancy involving complete hydatidiform mole andtwo fetuses: Genetic analysis by deoxyribonucleic acid fingerprint

Chihiro Azuma; Fumitaka Saji; Masahiko Takemura; Kazutomo Ohashi; Tadashi Kimura; Akira Miyake; Tetsu Takagi; Osamu Tanizawa

A case of a triplet pregnancy involving a dizygous twin pregnancy and a complete hydatidiform mole after therapy with human menopausal gonadotropin and human chorionic gonadotropin is reported. Two female fetuses, two placentas in one mass with two amnions and two chorions, and a tumor mass with a grapelike appearance were spontaneously delivered at 19 weeks of gestation. The deoxyribonucleic acid fingerprints of the two placentas and tumor tissue were compared with those of the parents. The fingerprints of the placentas showed patterns different from each other; however, all their polymorphic fragments could be traced back to either the father or mother. All polymorphic fragments of the tumor tissue were inherited only from the father (androgenesis). These results indicated that this triplet pregnancy involved a dizygous twin pregnancy and a complete hydatidiform mole.


American Journal of Reproductive Immunology | 1990

Gene expression of macrophage colony-stimulating factor and its receptor in human placenta and decidua.

Fumitaka Saji; Chihiro Azuma; Tadashi Kimura; Masayasu Koyama; Kazutomo Ohashi; Osamu Tanizawa

ABSTRACT: Macrophage colony‐stimulating factor (M‐CSF) induces proliferation of monocyte/macrophage progenitor cells and can also activate some functions of mature cells including fetally derived placental cells. To study the role of M‐CSF in the pregnant female reproductive tract, the expression of M‐CSF mRNA and its receptor, c‐fms proto‐oncogene, in human placenta and decidua was identified. M‐CSF and c‐fms mRNAs, 4.7Kb and 3.9Kb respectively, were detected by Northern blotting in the early stage placenta and subsequently increased during pregnancy. These mRNAs were not detected in the nonpregnant endometrium but were strongly induced in maternal decidua with the same mRNA size as in the placenta. Northern blot hybridization on the endometrium of a pseudopregnant uterus revealed that the expression of endometrial M‐CSF and c‐fms mRNAs is regulated by synergistic action of female sex steroid hormones. These findings indicate that, in an autocrine and/or paracrine manner, M‐CSF is deeply involved in the local proliferation and differentiation of cells at the materno‐fetal interface, and support the placental immunotrophism hypothesis.


American Journal of Obstetrics and Gynecology | 1989

Zygosity determination of multiple pregnancy by deoxyribonucleic acid fingerprints

Chihiro Azuma; Shoji Kamiura; Toshikatsu Nobunaga; Takao Negoro; Fumitaka Saji; Osamu Tanizawa

We used a new method of deoxyribonucleic acid analysis to determine zygosity in multiple pregnancies. This method uses a minisatellite core probe, requires only a small amount of deoxyribonucleic acid, and detects the restriction fragment length polymorphisms that are a result of allelic differences in the number of tandem repeats that contain the core sequence. Southern blot hybridization showed an individual-specific deoxyribonucleic acid fingerprint and each polymorphic band in the sibling could be identified within one (but not both) of the parents. Identical deoxyribonucleic acid fingerprints among the siblings of multiple pregnancy indicate they must be monozygotic. This method is sufficiently reliable and rapid so the determination of zygosity in multiple pregnancy can be made the same day the fetal deoxyribonucleic acid is made available.


The Journal of Steroid Biochemistry and Molecular Biology | 1992

Estimation by an electrophysiological method of the expression of oxytocin receptor mRNA in human myometrium during pregnancy

Tadashi Kimura; Chihiro Azuma; Fumitaka Saji; Masahiko Takemura; Yoshihiro Tokugawa; Mariko Miki; Masaaki Ono; Kensaku Mori; Osamu Tanizawa

In order to evaluate the changes in uterine oxytocin receptor-specific mRNA during pregnancy, receptor expression in Xenopus oocytes are examined electrophysiologically following microinjection of mRNA from human uterus. In voltage-clamped oocytes injected with term myometrial mRNA, oxytocin elicited an inward current response. The amplitude of the oxytocin-induced current increased with increasing dose of oxytocin, but no current was elicited following stimulation with vasopressin. The oxytocin-induced current was completely eliminated as a result of pretreatment with a specific oxytocin antagonist. 21 of 27 oocytes injected with term myometrial mRNA showed a large amplitude (77.0 +/- 16.1 nA) reaction to oxytocin. In comparison, only 3 of 13 oocytes injected with early gestational myometrial mRNA exhibited a small amplitude (4.6 +/- 1.4 nA) reaction to oxytocin. No oxytocin response was observed in oocytes injected with non-pregnant myometrial mRNA. These results indicate that the striking increment in oxytocin sensitivity in term uterus depends on the increase in mRNA encoding oxytocin receptors.


Fertility and Sterility | 1999

Two-color fluorescence staining of lectin and anti-CD46 antibody to assess acrosomal status.

Akiko Kawamoto; Kazutomo Ohashi; Hidefumi Kishikawa; Li-Qun Zhu; Chihiro Azuma; Yuji Murata

OBJECTIVE To examine potential methods for distinguishing between the acrosome reaction and acrosomal loss. DESIGN Prospective randomized study. SETTING Department of Obstetrics and Gynecology, Osaka University Hospital, Suita, Japan. PATIENT(S) Five healthy volunteers and 34 patients with normozoospermia who were participating in an IVF program. INTERVENTION(S) Semen samples were collected from the volunteers before the hamster egg penetration assay and from the patients at the time of IVF. MAIN OUTCOME MEASURE(S) The numbers of oocytes penetrated and spermatozoa bound were determined with the hamster egg penetration assay. Acrosomal status was assessed with two-color fluorescence staining using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA) and MH61 (anti-CD46 monoclonal antibody) with Texas red-conjugated antimouse immunoglobulin G antiserum. RESULT(S) The MH61 monoclonal antibody inhibited the penetration of human spermatozoa into hamster oocytes but did not reduce the number of spermatozoa bound to the zona-free hamster oocytes. Two-color fluorescence staining revealed four staining patterns of the acrosomal region. The percentage of PSA-negative/CD46-positive spermatozoa increased to a greater extent than that of PSA-negative/CD46-negative spermatozoa with an increase in the incubation time. CONCLUSION(S) Two-color fluorescence staining with FITC-PSA and the anti-CD46 monoclonal antibody may be useful for distinguishing between the acrosome reaction and acrosomal loss.


Breast Cancer Research and Treatment | 1995

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

Kazuyoshi Motomura; Hiroki Koyama; Shinzaburo Noguchi; Hideo Inaji; Chihiro Azuma

SummaryIn 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.

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