Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Tomoya Segawa is active.

Publication


Featured researches published by Tomoya Segawa.


Fertility and Sterility | 2003

Successful treatment of a symptomatic uterine leiomyoma in a perimenopausal woman with a nonsteroidal aromatase inhibitor.

Makio Shozu; Kouichi Murakami; Tomoya Segawa; Tadayuki Kasai; Masaki Inoue

OBJECTIVE To assess the management of symptomatic leiomyomas using a nonsteroidal aromatase inhibitor in perimenopausal women. DESIGN Case report. SETTING Academic clinical practice. PATIENT(S) A 53-year-old woman suffering from recurrent urinary retention secondary to a uterine leiomyoma. INTERVENTION(S) Fadrozole, orally, 2 mg daily for 8 weeks and then 1 mg daily for 4 weeks. MAIN OUTCOME MEASURE(S) Measurements of leiomyoma volume, and levels of serum E(2), LH, and FSH. RESULT(S) Urinary retention resolved after 2 weeks of treatment and did not recur. Leiomyoma volume estimated by ultrasonography revealed a 71% reduction after 8 weeks of treatment. CONCLUSION(S) Fadrozole was useful for the management of a symptomatic leiomyoma without transient deterioration of symptoms. Clinical trials are warranted.


Reproductive Biology and Endocrinology | 2012

Minimal ovarian stimulation combined with elective single embryo transfer policy: age-specific results of a large, single-centre, Japanese cohort

K. Kato; Y. Takehara; Tomoya Segawa; Satoshi Kawachiya; Takashi Okuno; T. Kobayashi; Daniel Bodri; O. Kato

BackgroundThe two main complications associated with the use of assisted reproduction techniques, ovarian hyperstimulation syndrome and multiple pregnancies, could be eliminated by milder ovarian stimulation protocols and the increased use of a single embryo transfer (SET) policy. A retrospective, cohort study was performed in private infertility centre to evaluate the embryological and clinical results of a large exclusively SET program according to patient age (lower or equal 29, 30–34, 35–39, 40–44 and equal or higher 45 years).MaterialsA total of 7,244 infertile patients have undergone 20,244 cycles with a clomiphene-based minimal stimulation or natural cycle IVF protocol during 2008. Following oocyte retrieval, fertilization and embryo culture a total of 10,401 fresh or frozen single embryo transfer procedures were performed involving cleavage-stage embryos or blastocysts.ResultsSuccessful oocyte retrieval rate (78.0 %) showed no age-dependent decrease until 45 years. Fertilization (80.3 %) and cleavage (91.1 %) rates were not significantly different between age groups. Blastocyst formation (70.1 % to 22.8 %) and overall live birth rates (35.9 % to 2 %) showed an age-dependent decrease. Frozen-thawed blastocyst transfer cycles gave the highest chance of live birth per embryo transfer (41.3 % to 6.1 %).ConclusionsHigh fertilization and cleavage rates were obtained regardless of age whereas blastocyst formation and live birth rates showed an age-dependent decrease. An elective single embryo transfer program based on a minimal ovarian stimulation protocol yields acceptable live birth rates per embryo transfer in infertile patients up until their mid-forties. However in very advanced age patients (equal or higher 45 years old) success rates fall below 1 %.


Clinical Cancer Research | 2005

Aromatase Expression in Stromal Cells of Endometrioid Endometrial Cancer Correlates with Poor Survival

Tomoya Segawa; Makio Shozu; Kouich Murakami; Tadayuki Kasai; Kazunori Shinohara; Kazuhito Nomura; Satoshi Ohno; Masaki Inoue

Purpose and Experimental Design: To assess the prognostic significance of intratumoral aromatase in endometrioid endometrial cancer, sections from 55 patients with endometrial cancer were evaluated for expression of aromatase using immunohistochemistry, and the correlation between aromatase expression and clinicopathologic parameters were analyzed. Results: Immunohistochemical staining for aromatase was positive for 32 (58%), 20 (36%), and 19 (34%) patients in cancer epithelial cells, stromal cells, and myometrial cells around the flank invasion, respectively. In situ hybridization also detected aromatase mRNA in all three types of cells. RT-PCR analysis revealed that aromatase mRNA was 2.5 ± 1.0 amol/μg total RNA (mean ± SE; n = 7) in tumor tissue. Western blot analysis detected the expected aromatase protein size of 58 kDa in cancer tissues more abundantly than in cancer-free endometrium (n = 3). The immunoreactivity in stromal cells correlated positively with advanced surgical stage and poor survival. Survival analysis revealed that the immunoreactivity of stromal cells was a significant prognostic factor, independent of histologic grade, muscular invasion, and lymph node metastasis, but dependent on surgical stage. By contrast, the immunoreactivity of aromatase both in cancer epithelial cells and myometrial cells did not correlate with prognosis. Conclusions: To the best of our knowledge, this is the first evidence associating intratumoral aromatase expression in stromal cells and poor survival in endometrioid endometrial cancer. This positive linkage indicates that local expression of aromatase plays a role in tumor progression through the formation of in situ estrogens. In situ expression of aromatase may offer a potential target for management of endometrial cancers.


International Journal of Cancer | 2001

Hybrid capture-II and LCR-E7 PCR assays for HPV typing in cervical cytologic samples.

Hiroshi Yamazaki; Toshiyuki Sasagawa; Walid Basha; Tomoya Segawa; Masaki Inoue

As part of an ongoing cohort study in the Hokuriku region of Japan, cervical cell samples from histologically confirmed normal (n = 114) or abnormal (n = 286) women were examined for the presence of HPV DNA using a second‐generation hybrid capture assay (HCA‐II) and LCR‐E7 PCR. HCA‐II detected low‐risk (HPV‐6, ‐11, ‐42, 43 and ‐44) and high‐risk (HPV‐16, ‐18, ‐31, ‐33, ‐35, ‐39, ‐45, ‐51, ‐52, ‐56, ‐58, ‐59 and ‐68) HPV types, while LCR‐E7 PCR detected an additional 7 HPV types and some uncharacterized types. In screening of high‐grade squamous intraepithelial lesions (HSILs) and invasive cervical cancer, the sensitivities of HCA‐II and LCR‐E7 PCR testing the high‐risk HPV types were 83% and 81%, respectively, while the specificity of both assays was 93%. The sensitivity of LCR‐E7 PCR increased to 87%, which was significantly higher than that in HCA‐II, when testing both high‐risk and other HPV types. Sixty‐eight inconsistent results (17% of total tested) from HCA‐II and LCR‐E7 PCR were due to (i) low copy number of HPV genome (false‐negative for HCA‐II, 5.3% and for LCR‐E7 PCR, 1.3%), (ii) infection with HPV types undetectable by HCA‐II (4.8%), (iii) multiple HPV infections (5%) or (iv) unknown reasons (0.8%). LCR‐E7 PCR revealed that infections with HPV‐16, ‐18, ‐31, ‐33, ‐35, ‐51, ‐52, ‐56, ‐58 or ‐67 was a high risk for cancer since these types predominated in HSIL and invasive cervical cancer. Samples showing high relative light units (>20) with a high‐risk probe in HCA‐II also gave positive results in LCR‐E7 PCR and were generally associated with abnormal cervical lesions. Thus, we propose that both HCA‐II and LCR‐E7 PCR are valuable screening tests for premalignant and malignant cervical lesions.


The Journal of Steroid Biochemistry and Molecular Biology | 2001

Regulation of aromatase activity in bone-derived cells: possible role of mitogen-activated protein kinase

Makio Shozu; Hiroshi Sumitani; Kouichi Murakami; Tomoya Segawa; Hei-Juan Yang; Masaki Inoue

Fetal human osteoblast-like cells and the THP-1 cell line that differentiates into macrophage/osteoblast-like cells in the presence of Vitamin D3 and which possesses high aromatase activity, constitute a useful model with which to study the regulation of aromatase in bone. We showed that dexamethasone (DEX)-induced aromatase activity in the THP-1 cell line is completely suppressed by forskolin and by dibutyryl cAMP. We therefore investigated the contribution of mitogen-activated protein kinase (MAPK) to the regulation of aromatase, because cAMP inhibits MAPK in many cells. We examined the role of MAPK on aromatase activity using PD98059, a selective inhibitor of MEK-1. PD98059 (100 microM) reduced DEX+interleukin (IL)-1beta-induced aromatase activity in human osteoblast-like cells by more than 90%, whereas 50% of the aromatase mRNA concentration was retained compared with the control incubated with DEX+IL-1beta. PD98059 (50 microM) reduced the activity of aromatase in THP-1 cells by 80% without significantly affecting the mRNA level. These results indicated that MAPK plays an important role in aromatase activation at the post-transcriptional level.


Cancer Research | 2004

Decreased Expression of Early Growth Response-1 and Its Role in Uterine Leiomyoma Growth

Makio Shozu; Kouichi Murakami; Tomoya Segawa; Tadayuki Kasai; Hiroshi Ishikawa; Kazunori Shinohara; Masahiko Okada; Masaki Inoue

Expression of early growth response (Egr)-1, a transcriptional factor implicated in growth regulation, is suppressed in several malignant tumors. The present study investigated the expression of Egr-1 and related genes in uterine leiomyoma and normal myometrium to determine possible contributions of Egr-1 to neoplastic growth in leiomyoma cells. Levels of Egr-1 transcripts were decreased in all leiomyomas (n = 20) to approximately 10% of levels in corresponding myometrium, where basal expression was high. Preoperative leuprorelin acetate therapy increased levels of Egr-1 mRNA in normal myometrium only. Northern blot analysis using additional sample sets (n = 5) revealed the full-length Egr-1 transcript. Western blot analysis (n = 5) confirmed decreased expression of Egr-1 protein. Southern blot analysis of the Egr-1 gene and microsatellite analysis of the chromosomal location at 5q31 (D5S414, D5S500, and D5S476) revealed neither DNA recombination nor loss of heterozygosity in leiomyomas. Moreover, Egr-1 retained identical responsiveness to phorbol 12-myristate 13-acetate in primary cultures derived from both leiomyoma and normal tissues. Electrophoretic mobility shift analysis revealed that phorbol 12-myristate 13-acetate-induced Egr-1 in leiomyoma cells retained DNA binding ability. Egr-1 thus appears functionally intact in leiomyoma cells. Finally, consistent with the role of Egr-1 in growth inhibition, transfection of Egr-1 expression vector into a myometrial cell line (KW) that expresses low levels of Egr-1 and displays rapid growth inhibited thymidine uptake in these cells. Egr-1 may display tumor-suppressing activity and offers a potential target for leiomyoma management.


Obstetrics & Gynecology | 2001

Leak-proof puncture of ovarian cysts: instant mounting of plastic bag using cyanoacrylate adhesive

Makio Shozu; Tomoya Segawa; Hiroshi Sumitani; Masaki Inoue

Background Reliable leak-proof aspiration of cyst contents is required for treatment of large ovarian cysts by minilapa-rotomy. Technique Through a small abdominal wound a transparent plastic bag was instantly mounted onto the cyst surface using an ethyl-2-cyanoacrylate adhesive. A 1–2-cm-wide cut was made in the consolidated cyst wall through the inside of the bag and the contents directly aspirated. The fluid was trapped inside the bag without leaking into the abdominal cavity. This method can also be applied to relatively small cysts by holding the cyst just beneath the wound. Experience We used this method in 30 patients with unilateral ovarian cysts and in one patient with an ovarian cyst associated with an ipsilateral paraovarian cyst. All patients were successfully treated without spillage, although in one case a large mucinous ovarian cyst ruptured before surgery. Conclusion Minilaparotomy using the instant adhesive is cost-effective, safe, reliable, and easily implemented. This procedure is also applicable to relatively small cysts and is a viable alternative to laparoscopic surgery for treatment of dermoid cysts showing considerable calcification.


Journal of Obstetrics and Gynaecology Research | 2004

Sex-determining region Y levels in maternal plasma: Evaluation in abnormal pregnancy.

Keiko Shimada; Kouichi Murakami; Makio Shozu; Tomoya Segawa; Hiroshi Sumitani; Masaki Inoue

Aim:  A number of studies for the measurement of cell‐free fetal DNA in maternal blood have been reported; however, their clinical significance has remained unclear. We proposed to clarify the relationship between fetal DNA levels and obstetrical disorders.


Reproductive Biomedicine Online | 2014

Women's age and embryo developmental speed accurately predict clinical pregnancy after single vitrified-warmed blastocyst transfer

Keiichi Kato; Satoshi Ueno; Akiko Yabuuchi; Kazuo Uchiyama; Takashi Okuno; T. Kobayashi; Tomoya Segawa; S. Teramoto

The aim of this study was to establish a simple, objective blastocyst grading system using womens age and embryo developmental speed to predict clinical pregnancy after single vitrified-warmed blastocyst transfer. A 6-year retrospective cohort study was conducted in a private infertility centre. A total of 7341 single vitrified-armed blastocyst transfer cycles were included, divided into those carried out between 2006 and 2011 (6046 cycles) and 2012 (1295 cycles). Clinical pregnancy rate, ongoing pregnancy rate and delivery rates were stratified by womens age (<35, 35-37, 38-39, 40-41, 42-45 years) and time to blastocyst expansion (<120, 120-129, 130-139, 140-149, >149 h) as embryo developmental speed. In all the age groups, clinical pregnancy rate, ongoing pregnancy rate and delivery rates decreased as the embryo developmental speed decreased (P < 0.0001). A simple five-grade score based on womens age and embryo developmental speed was determined by actual clinical pregnancy rates observed in the 2006-2011 cohort. Subsequently, the novel grading score was validated in the 2012 cohort (1295 cycles), finding an excellent association. In conclusion, we established a novel blastocyst grading system using womens age and embryo developmental speed as objective parameters.


Reproductive Biomedicine Online | 2017

Cytogenetic analysis of the retained products of conception after missed abortion following blastocyst transfer: a retrospective, large-scale, single-centre study

Tomoya Segawa; Tomoko Kuroda; K. Kato; Masako Kuroda; Kenji Omi; Osamu Miyauchi; Yoshiaki Watanabe; Tsuyoshi Okubo; Hisao Osada; S. Teramoto

Cytogenetic analysis of the retained products of conception (POC) is the most effective test for identifying miscarriage causes. However, there has been no large-scale study limited to blastocyst transfer. This study retrospectively reports the findings of 1030 cases in which POC analysis was performed after missed abortion following single blastocyst transfer performed at the Shinbashi Yume Clinic. We identified 19.4% as normal karyotypes and 80.6% as aneuploid. These cases broke down into: 62.3% trisomy; 7.8% double trisomy; 0.5% triple or quadruple trisomy; 1.3% monosomy 21; 3.2% monosomy X; 0.1% 47,XXY; 1.0% polyploidy; 1.0% mixed; 1.1% embryonic mosaicism; and 2.4% structural anomalies. In samples with normal karyotypes, 49.5% were female while 50.5% were male. The occurrence of trisomy and double trisomy were both significantly more frequent in the ≥38 years group than in the ≤37 years group (P < 0.01). Trisomy was significantly more frequently associated with fetal heartbeat (P < 0.01); double trisomy, polyploidy and normal karyotype were significantly more frequent with no fetal heartbeat (P < 0.01). There was no significant difference in the frequency of chromosomal abnormalities between the number of miscarriages or blastocyst quality. Thus, POC cytogenetic testing is highly valuable for ascertaining the cause of miscarriage.

Collaboration


Dive into the Tomoya Segawa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

K. Kato

Heidelberg University

View shared research outputs
Top Co-Authors

Avatar

O. Kato

University of California

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge