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Dive into the research topics where Tomomi Kotani is active.

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Featured researches published by Tomomi Kotani.


Journal of Obstetrics and Gynaecology Research | 2007

Placenta previa increta/percreta in Japan: A retrospective study of ultrasound findings, management and clinical course

Seiji Sumigama; Atsuo Itakura; Toyohiro Ota; Mayumi Okada; Tomomi Kotani; Hiromi Hayakawa; Kana Yoshida; Kaoru Ishikawa; Kazumasa Hayashi; O. Kurauchi; Satoru Yamada; Hiromi Nakamura; Katsuji Matsusawa; Katsumi Sakakibara; Mitsuaki Ito; Michiyasu Kawai; Fumitaka Kikkawa

Aim:  Placenta accreta is an abnormally firm attachment of placental villi to the uterine wall, which may cause postpartum hemorrhage resulting in maternal morbidity and mortality. The purpose of the present study was to clarify the incidence, clinical background and prognosis of placenta previa increta/percreta treated with different modalities in Japan.


Fertility and Sterility | 2012

Sphingosine-1-phosphate inhibits H2O2-induced granulosa cell apoptosis via the PI3K/Akt signaling pathway

Tatsuo Nakahara; Akira Iwase; Tomoko Nakamura; Bayasula; Hiroharu Kobayashi; Sachiko Takikawa; Shuichi Manabe; Maki Goto; Tomomi Kotani; Fumitaka Kikkawa

OBJECTIVE To investigate the protective effect of sphingosine-1-phosphate (S1P) against H(2)O(2)-induced apoptosis in human granulosa cell cultures with freshly harvested granulosa cells. DESIGN Experimental study. SETTING Academic medical center for reproductive medicine. PATIENT(S) Cultures of primary granulosa cells isolated from women undergoing in vitro fertilization (IVF). INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Cell apoptosis and Western blot analysis of signaling pathway proteins. RESULT(S) We found that S1P (1 and 10 mM) statistically significantly decreased granulosa cell apoptosis after H(2)O(2) treatment. The decreased cell apoptosis induced by S1P was abolished after treatment with VPC23019, an inhibitor of S1P1 and S1P3 receptors, W146, an inhibitor of S1P1 receptors, and CAY10444, an inhibitor of S1P3 receptors. A Western blot analysis revealed that the level of phospho-Akt increased and peaked at 10 minutes after 10 mM S1P exposure. CONCLUSION(S) Treatment with S1P can inhibit the apoptosis of granulosa cells in response to oxidative stress induced by H(2)O(2). The protective effect of S1P is mediated by activating the PI3K/Akt pathway, and the antiapoptotic effect of S1P is mainly mediated through the S1P1 and S1P3 receptor.


Endocrinology | 2011

The Loss of Endoglin Promotes the Invasion of Extravillous Trophoblasts

Yukio Mano; Tomomi Kotani; Kiyozumi Shibata; Hiroko Matsumura; Hiroyuki Tsuda; Seiji Sumigama; Eiko Yamamoto; Akira Iwase; Takeshi Senga; Fumitaka Kikkawa

Endoglin is a coreceptor for TGF-β, which is expressed in syncytiotrophoblasts. The soluble form of endoglin (sEng) has been observed to increase in the serum of preeclamptic patients. Several studies have shown that endoglin is involved in cancer invasion. However, the role of endoglin in extravillous trophoblasts (EVT), which have an invasive phenotype, remains unknown. The present study was designed to investigate the expression and role of endoglin in human EVT. We found that endoglin was mainly expressed on cytotrophoblasts within the cell column during the first trimester and its expression decreased in the EVT by immunohistochemistry and immunocytochemistry. The expression of endoglin significantly increased after treatment with TGF-β1 and TGF-β3 in the human EVT cell line, HTR-8/SVneo, as detected by semiquantitative RT-PCR. To investigate the role of endoglin in EVT, the stable knockdown of endoglin was performed by lentiviral short hairpin RNA transfection into the HTR-8/SVneo cells. Although proliferation was not affected, the motility and invasiveness of the HTR-8/SVneo cells significantly increased by the knockdown of endoglin. Both the mRNA expression and secretion of urokinase-type plasminogen activator significantly increased in endoglin knockdown cells. The secretion of sEng was very low in HTR-8/SVneo, and the treatment of endoglin knockdown cells with 10 ng/ml sEng had no effect on their invasiveness. Therefore, the suppression of sEng was not involved in the increased invasiveness of endoglin knockdown cells. These results suggested that EVT increased their invasive function as a result of decreasing expression of transmembrane endoglin.


Endocrinology | 2009

Activator Protein-2 Impairs the Invasion of a Human Extravillous Trophoblast Cell Line

Tomomi Kotani; Akira Iwase; Kazuhiko Ino; Seiji Sumigama; Eiko Yamamoto; Hiromi Hayakawa; Tetsuo Nagasaka; Atsuo Itakura; Seiji Nomura; Fumitaka Kikkawa

The reduced migration/invasion of extravillous trophoblasts (EVTs) is a key feature of the genesis of preeclampsia. We and others previously reported that transcriptional factors activator protein-2 (AP-2) alpha and AP-2gamma act as suppressors of tumor invasion. The present study examined the expressions of AP-2alpha and AP-2gamma in preeclamptic placenta vs. control placenta and investigated their effect on the function of EVTs. The expressions of AP-2alpha and AP-2gamma were elevated in the preeclamptic placentas in comparison with the gestational age-matched control placentas. Their expressions also increased in EVTs of the preeclamptic placentas. Thereafter, we transfected AP-2alpha or AP-2gamma into human EVT cell line, HTR-8/SVneo. The overexpression of AP-2alpha or AP-2gamma decreased the migratory and invasive abilities in HTR-8/SVneo cells. This was followed by the reduction of protease activated receptor-1 and matrix metalloproteinases and a significant induction of plasminogen activator inhibitor-1 and the tissue inhibitor of metalloproteinase-1. AP-2alpha and AP-2gamma were weakly expressed in the cultured EVTs and HTR-8/SVneo cells, whereas they were induced by TNF-alpha, which increases in preeclamptic placenta and impairs trophoblast invasion. In the presence of TNF-alpha, the invasion of the HTR-8/SVneo cells was partially restored by a blocking of AP-2 induction using small interfering RNA of AP-2. The present data suggest that AP-2 may suppress trophoblast migration and invasion, thus leading to a shallow placentation in preeclampsia.


Free Radical Biology and Medicine | 2014

Maternal molecular hydrogen administration ameliorates rat fetal hippocampal damage caused by in utero ischemia–reperfusion

Yukio Mano; Tomomi Kotani; Mikako Ito; Taku Nagai; Yuko Ichinohashi; Kiyofumi Yamada; Kinji Ohno; Fumitaka Kikkawa; Shinya Toyokuni

Molecular hydrogen (H2) scavenges hydroxyl radicals. Recently, H2 has been reported to prevent a variety of diseases associated with oxidative stress in model systems and in humans. Here, we studied the effects of H2 on rat fetal hippocampal damage caused by ischemia and reperfusion (IR) on day 16 of pregnancy with the transient occlusion of the bilateral utero-ovarian arteries. Starting 2 days before the operation, we provided the mothers with hydrogen-saturated water ad libitum until vaginal delivery. We observed a significant increase in the concentration of H2 in the placenta after the oral administration of hydrogen-saturated water to the mothers, with less placental oxidative damage after IR in the presence of H2. Neonatal growth retardation was observed in the IR group, which was alleviated by the H2 administration. We analyzed the neuronal cell damage in the CA1 and CA3 areas of the hippocampus at day 7 after birth by immunohistochemical analysis of the 8-oxo-7,8-dihydro-2׳-deoxyguanosine- and 4-hydroxy-2-nonenal-modified proteins. Both oxidative stress markers were significantly increased in the IR group, which was again ameliorated by the H2 intake. Last, 8-week-old rats were subjected to a Morris water maze test. Maternal H2 administration improved the reference memory of the offspring to the sham level after IR injury during pregnancy. Overall, the present results support the idea that maternal H2 intake helps prevent the hippocampal impairment of offspring induced by IR during pregnancy.


Developmental Neuroscience | 2015

Administration of umbilical cord blood cells transiently decreased hypoxic-ischemic brain injury in neonatal rats.

Tetsuo Hattori; Yoshiaki Sato; Taiki Kondo; Yuko Ichinohashi; Yuichiro Sugiyama; Michiro Yamamoto; Tomomi Kotani; Hitoshi Hirata; Akihiro Hirakawa; Satoshi Suzuki; Masahiro Tsuji; Tomoaki Ikeda; Keiko Nakanishi; Seiji Kojima; Klas Blomgren; Masahiro Hayakawa

This study aimed to investigate whether the administration of mononuclear cells derived from human umbilical cord blood cells (UCBCs) could ameliorate hypoxic-ischemic brain injury in a neonatal rat model. The left carotid arteries of 7-day-old rats were ligated, and the rats were then exposed to 8% oxygen for 60 min. Mononuclear cells derived from UCBCs using the Ficoll-Hypaque technique were injected intraperitoneally 6 h after the insult (1.0 × 107 cells). Twenty-four hours after the insult, the number of cells positive for the oxidative stress markers 4-hydroxy-2-nonenal and nitrotyrosine, in the dentate gyrus of the hippocampus in the UCBC-treated group, decreased by 36 and 42%, respectively, compared with those in the control group. In addition, the number of cells positive for the apoptosis markers active caspase-3 and apoptosis-inducing factor decreased by 53 and 58%, respectively. The number of activated microglia (ED1-positive cells) was 51% lower in the UCBC group compared with the control group. In a gait analysis performed 2 weeks after the insult, there were no significant differences among the sham-operated, control and UCBC groups. An active avoidance test using a shuttle box the following week also revealed no significant differences among the groups. Neither the volumes of the hippocampi, corpus callosum and cortices nor the numbers of neurons in the hippocampus were different between the UCBC and control groups. In summary, a single intraperitoneal injection of UCBC-derived mononuclear cells 6 h after an ischemic insult was associated with a transient reduction in numbers of apoptosis and oxidative stress marker-positive cells, but it did not induce long-term morphological or functional protection. Repeated administration or a combination treatment may be required to achieve sustained protection.


British Journal of Obstetrics and Gynaecology | 2014

Uterine sutures at prior caesarean section and placenta accreta in subsequent pregnancy: a case–control study

Seiji Sumigama; C. Sugiyama; Tomomi Kotani; Hiromi Hayakawa; A Inoue; Yukio Mano; Hiroyuki Tsuda; Madoka Furuhashi; O Yamamuro; Y Kinoshita; T Okamoto; H Nakamura; K Matsusawa; K Sakakibara; H Oguchi; Michiyasu Kawai; Yoshie Shimoyama; Koji Tamakoshi; Fumitaka Kikkawa

To clarify the effects of uterine myometrial suture techniques at prior caesarean section on the incidence of pathologically diagnosed placenta accreta in placenta praevia with prior caesarean section (PPPC).


Journal of Assisted Reproduction and Genetics | 2013

A proteomic analysis of human follicular fluid: comparison between fertilized oocytes and non-fertilized oocytes in the same patient

Bayasula; Akira Iwase; Hiroharu Kobayashi; Maki Goto; Tatsuo Nakahara; Tomoko Nakamura; Yoshinari Nagatomo; Tomomi Kotani; Fumitaka Kikkawa

PurposeHuman follicular fluid constitutes the microenvironment of follicles and includes various biological active proteins that can affect follicle growth and oocyte fertilization. Conducting proteomic evaluations of human follicular fluid may be helpful for identifying potential biomarkers possibly possessing a predictive value for oocyte quality and the success of in vitro fertilization.MethodWe performed proteomic profiling of human follicular fluids containing oocytes that were fertilized and resulted in pregnancy and follicular fluids containing oocytes that were not fertilized in the same patients undergoing intracytoplasmic sperm injection using the LTQ Orbitrap coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) analyses.ResultsWe identified a total of 503 proteins in human follicular fluids containing fertilized and non-fertilized oocytes obtained from 12 patients. We also found that 53 proteins exhibited significantly different spectral counts between the two groups, including heparan sulfate proteoglycan perlecan, which showed significant upregulation in the follicular fluids containing fertilized oocytes in comparison with that observed in the follicular fluids containing non-fertilized oocytes.ConclusionOur results suggest a possibility that proteins identified by LC/MS/MS in follicular fluid might not only be involved in folliculogenesis, but also function as biomarkers possessing predictive potential for oocyte maturation and the success of IVF when their expression levels are significantly different between fertilized and non-fertilized oocytes, although no distinctive biomarkers were identified in the current study.


Endocrinology | 2012

Establishment of a Human Nonluteinized Granulosa Cell Line that Transitions from the Gonadotropin-Independent to the Gonadotropin-Dependent Status

Bayasula; Akira Iwase; Tohru Kiyono; Sachiko Takikawa; Maki Goto; Tomoko Nakamura; Yoshinari Nagatomo; Tatsuo Nakahara; Tomomi Kotani; Hiroharu Kobayashi; Shuichi Manabe; Fumitaka Kikkawa

The ovary is a complex endocrine organ responsible for steroidogenesis and folliculogenesis. Follicles consist of oocytes and two primary steroidogenic cell types, the granulosa cells, and the theca cells. Immortalized human granulosa cells are essential for researching the mechanism of steroidogenesis and folliculogenesis. We obtained granulosa cells from a 35-yr-old female and immortalized them by lentivirus-mediated transfer of several genes so as to establish a human nonluteinized granulosa cell line (HGrC1). We subsequently characterized HGrC1 and investigated its steroidogenic performance. HGrC1 expressed enzymes related to steroidogenesis, such as steroidogenic acute regulatory protein, CYP11A, aromatase, and gonadotropin receptors. Stimulation with FSH increased the mRNA levels of aromatase, which consequently induced the aromatization of androstenedione to estradiol. Activin A increased the mRNA levels of the FSH receptor, which were synergistically up-regulated with FSH stimulation. HGrC1 also expressed a series of ligands and receptors belonging to the TGF-β superfamily. A Western blot analysis showed that bone morphogenetic protein (BMP)-4, BMP-6, and BMP-7 phosphorylated small mother against decapentaplegic (Smad)1/5/8, whereas growth differentiation factor-9 phosphorylated Smad2/3. BMP-15 and anti-Müllerian hormone phosphorylated Smad1/5/8 while also weakly phosphorylating Smad2/3. These results indicate that HGrC1 may possess the characteristics of granulosa cells belonging to follicles in the early stage. HGrC1 might also be capable of displaying the growth transition from a gonadotropin-independent status to gonadotropin-dependent one.


Journal of Obstetrics and Gynaecology Research | 2011

Maternal mental disorders and pregnancy outcomes: A clinical study in a Japanese population

Masae Hironaka; Tomomi Kotani; Seiji Sumigama; Hiroyuki Tsuda; Yukio Mano; Hiromi Hayakawa; Satoshi Tanaka; Norio Ozaki; Koji Tamakoshi; Fumitaka Kikkawa

Aim:  To assess the maternal and neonatal outcomes of pregnant women with mental disorders in Japan.

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