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Featured researches published by Y. Takehara.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2012

Neonatal outcome and birth defects in 6623 singletons born following minimal ovarian stimulation and vitrified versus fresh single embryo transfer

O. Kato; Nami Kawasaki; Daniel Bodri; Tomoko Kuroda; Satoshi Kawachiya; K. Kato; Y. Takehara

OBJECTIVE To compare neonatal outcome between children born after vitrified versus fresh single-embryo transfer (SET). STUDY DESIGN Retrospective, single-centre cohort study of 6623 delivered singletons following 29,944 single-embryo transfers. Patients underwent minimal ovarian stimulation/natural cycle IVF followed by SET of fresh or vitrified-warmed (using Cryotop, Kitazato) cleavage-stage embryos or blastocysts. Outcome measures were gestational age at delivery, birth weight, birth length, low birth weight (LBW), small for gestational age (SGA) and large for gestational age (LGA) infants, perinatal mortality and minor/major birth defects (evaluated by parent questionnaire). RESULTS Gestational age (38.6 ± 2 versus 38.7 ± 1.9 weeks) and preterm delivery rate (6.9% versus 6.9%, aOR: 0.96 95%CI: 0.76-1.22) in singletons born after the transfer of vitrified embryos were comparable to those born after the transfer of fresh embryos. Children born after the transfer of vitrified embryos had a higher birth weight (3028 ± 465 versus 2943 ± 470 g, p<0.0001) and lower LBW (8.5% versus 11.9%, aOR: 0.65 95%CI: 0.53-0.79) and SGA (3.6% versus 7.6% aOR: 0.43 95%CI: 0.33-0.56) rates. Total birth defect rates (including minor anomalies) (2.4% versus 1.9%, aOR: 1.41 95%CI: 0.96-2.10) and perinatal mortality rates (0.6% versus 0.5%, aOR: 1.02 95%CI: 0.21-4.85) were comparable between the vitrified and fresh groups. CONCLUSIONS Vitrification of embryos/blastocysts did not increase the incidence of adverse neonatal outcomes or birth defects following single embryo transfer.


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 %.


Laboratory Investigation | 2013

The restorative effects of adipose-derived mesenchymal stem cells on damaged ovarian function

Y. Takehara; Akiko Yabuuchi; Kenji Ezoe; Tomoko Kuroda; Rie Yamadera; Chiaki Sano; Nana Murata; Takuya Aida; Ken Nakama; F. Aono; Naoki Aoyama; Keiich Kato; Osamu Kato

The clinical application of human adipose-derived mesenchymal stem cells (MSCs) as treatment for intractable diseases or traumatic tissue damage has attracted attention. To address the ability of reactivating injured ovaries, we prepared a rat model with damaged ovaries by using an anticancer agent, cyclophosphamide (CTX). We then investigated the restorative effects on ovarian function and the safety of adipose-derived MSCs (A-MSCs). MSCs were shown to be capable of inducing angiogenesis and restoring the number of ovarian follicles and corpus lutea in ovaries. No deformities, tumor formation or deaths were observed in F1 and F2 rats, indicating that the local injection of MSCs into the ovary did not have any obvious side effects. In addition, the localization of the Y chromosome was investigated using the fluorescent in situ hybridization method by injecting male A-MSCs into the ovaries; as a result, the Y chromosomes were localized not in the follicles, but in the thecal layers. ELISA revealed that A-MSCs secreted higher levels of vascular endothelial cell growth factor (VEGF), insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) than tail fibroblast cells. Quantitative real-time PCR and immunohistochemistry showed that higher expression levels of VEGF, IGF-1 and HGF were observed in CTX-treated ovaries after A-MSC transplantation. These findings suggest that MSCs may have a role in restoring damaged ovarian function and could be useful for regenerative medicine.


Fertility and Sterility | 2011

Blastocyst culture is associated with an elevated incidence of monozygotic twinning after single embryo transfer.

Satoshi Kawachiya; Daniel Bodri; Naoko Shimada; K. Kato; Y. Takehara; O. Kato

In a 7-year (2002-2008) retrospective study of a large IVF program based on minimal ovarian stimulation and single ET (47,841 single ETs), monozygotic twinning occurred in 1.01% of 14,956 clinical pregnancies. Blastocyst culture was associated with a significantly increased monozygotic twinning risk (adjusted odds ratio, 2.04; 95% confidence interval, 1.29-4.48), whereas embryo freezing, type of stimulation protocol used, intracytoplasmic sperm injection fertilization, or zona removal did not influence its incidence.


Reproductive Biomedicine Online | 2012

Short-term, low-dose, non-steroidal anti-inflammatory drug application diminishes premature ovulation in natural-cycle IVF

Satoshi Kawachiya; Tsunekazu Matsumoto; Daniel Bodri; K. Kato; Y. Takehara; O. Kato

A retrospective cohort study was conducted in a private infertility centre to evaluate the use of non-steroidal antiinflammatory drugs (NSAID) in natural-cycle IVF (nIVF) treatment. A total of 1865 first-rank nIVF cycles performed during 2009–2010 were evaluated. Low-dose, post-trigger NSAID was administered in a non-randomized way in cycles at higher ovulation risk where an imminent LH surge was detected on triggering day. Main outcome measures were premature ovulation rate, embryo transfer rate per scheduled cycle and clinical pregnancy and live birth rates per embryo transfer. NSAID use was associated with a significantly lower risk of premature ovulation (3.6% versus 6.8%, adjusted OR 0.24, 95% CI 0.15–0.39, P < 0.0001) and higher embryo transfer rate (46.8% versus 39.5%, adjusted OR 1.38, 95% CI 1.06–1.61, P = 0.012) per scheduled cycle. Clinical pregnancy (39.1% versus 35.9%) and live birth rates per embryo transfer (31.3% versus 31.4%) were comparable. In this retrospective series, short-term low-dose NSAID application positively influenced nIVF cycles by diminishing the rate of unwanted premature ovulations and increasing the proportion of cycles reaching embryo transfer.


Hormone Research in Paediatrics | 1991

Effects of prolactin on fertilization and cleavage of human oocytes.

Takahisa Oda; Yasunori Yoshimura; Y. Takehara; S. Kohriyama; Y. Sano; Kiyoo Tanabe; T. Kobayashi; Yukio Nakamura; T. Ohno; Shiro Nozawa

The effects of PRL on fertilization and cleavage of human oocytes and subsequent pregnancy were studied. Forty-five patients (47 cycles) with euprolactinemic normal menstrual cycles undergoing in vitro fertilization (IVF) for the treatment of tubal infertility were selected for this study. The patients were divided into three groups dependent upon their mean serum PRL concentrations for the 3 days prior to oocyte retrieval; hypoprolactinemic (less than 10 micrograms/l), euprolactinemic (10-30 micrograms/l) and hyperprolactinemic cycles (greater than or equal to 30 micrograms/l). Multiple follicular development was induced with hMG, and 10 patients were randomized to receive bromocriptine beginning with the previous menstrual cycle. In the hypoprolactinemic cycle group, the fertilization rate was significantly lower than in the hyperprolactinemic cycle group, and the cleavage rate was significantly lower than in the other groups. The fertilization rates and the cleavage rates in the hyperprolactinemic cycle group were higher than those in the euprolactinemic cycle group; however, these differences were not statistically significant. While the pregnancy rates in the euprolactinemic cycle group were higher than in the other two groups, the numbers were too small for meaningful statistical comparison. The present study demonstrates that below normal concentrations of PRL have deleterious effects on IVF outcome. These data suggest that PRL may play a beneficial stimulatory role in oocyte maturation and the acquisition of developmental capacity.


Biochimica et Biophysica Acta | 2012

Prevention of mitochondrial disease inheritance by assisted reproductive technologies: Prospects and challenges

Akiko Yabuuchi; Zeki Beyhan; Noriko Kagawa; Chiemi Mori; Kenji Ezoe; K. Kato; F. Aono; Y. Takehara; Osamu Kato

BACKGROUND Mitochondrial diseases are caused by the mutations in both nuclear and mitochondrial DNA (mtDNA) and the treatment options for patients who have mitochondrial disease are rather limited. Mitochondrial DNA is transmitted maternally and does not follow a Mendelian pattern of inheritance. Since reliable and predictable detection of mitochondrial disorders in embryos and oocytes is unattainable at present, an alternative approach to this problem has emerged as partial or complete replacement of mutated mtDNA with the wild-type mtDNA through embryo manipulations. Currently available methods to achieve this goal are germinal vesicle transfer (GVT), metaphase chromosome transfer (CT), pronuclear transfer (PNT) and ooplasmic transfer (OT). SCOPE OF REVIEW We summarize the state of the art regarding these technologies and discuss the implications of recent advances in the field for clinical practice. MAJOR CONCLUSIONS CT, PNT and GVT techniques hold promise to prevent transmission of mutant mtDNA through ARTs. However, it is clear that mtDNA heteroplasmy in oocytes, embryos and offspring produced by these methods remains as a legitimate concern. GENERAL SIGNIFICANCE New approaches to eliminate transmission of mutant mtDNA certainly need to be explored in order to bring the promise of clinical application for the treatment of mitochondrial disorders. This article is part of a Special Issue entitled Biochemistry of Mitochondria, Life and Intervention 2010.


Fertility and Sterility | 1991

Androstenedione and progesterone concentrations in preovulatory follicular fluid correlate with successful fertilization and cleavage of human oocytes in vitro**Presented at the 7th Annual Meeting of the Society of Japan Fertilization and Implantation, Fukui, Japan, July 15 to 16, 1989.

T. Kobayashi; Takahisa Oda; Yasunori Yoshimura; Y. Takehara; Michiya Natori; Shiro Nozawa

OBJECTIVE To determine if androstenedione (A) and progesterone (P) concentrations in preovulatory follicular fluid (FF) correlate with successful fertilization and cleavage of human oocytes in vitro. DESIGN A retrospective randomized trial. SETTING Hospital department of obstetrics and gynecology. PATIENTS Fifty-five patients, ages 24 to 39 years, with normal menstrual cycles undergoing in vitro fertilization (IVF) for tubal infertility. INTERVENTIONS Multiple follicular development was induced with clomiphene citrate and human menopausal gonadotropin. MAIN OUTCOME MEASURES Relationships among FF steroid hormone, morphological maturity of oocyte-corona-cumulus complexes, and fertilization and cleavage of oocytes. RESULTS Follicles with mature oocyte-corona-cumulus complexes and unfertilized oocytes contained significantly greater amounts of A (P less than 0.05) than those with mature oocyte-corona-cumulus complexes and fertilized ova, indicating the occurrence of atretic changes. Follicles yielding successfully fertilized and cleaved ova had significantly greater amounts of P (P less than 0.05) and A (P less than 0.01) but similar levels of 17 beta-estradiol compared with follicles yielding fertilized ova that failed to cleave. CONCLUSIONS Follicles yielding oocytes that cleaved as a result of IVF have both a shift in steroidogenesis from estrogen to progestin accumulation and declining aromatase activity, thus reflecting progressive luteinization of the follicles.


Human Reproduction | 2013

Reproductive and obstetric outcomes after radical abdominal trachelectomy for early-stage cervical cancer in a series of 31 pregnancies

Hiroshi Nishio; Takuma Fujii; Juri Sugiyama; Naoaki Kuji; Mamoru Tanaka; Toshio Hamatani; Kei Miyakoshi; Kazuhiro Minegishi; Hiroshi Tsuda; Takashi Iwata; Kyoko Tanaka; Takeshi Fukuchi; Y. Takehara; Yasunori Yoshimura; Daisuke Aoki


Fertility and Sterility | 1991

Androstenedione and progesterone concentrations in preovulatory follicular fluid correlate with successful fertilization and cleavage of human oocytes in vitro

Toshifumi Kobayashi; Takahisa Oda; Yasunori Yoshimura; Y. Takehara; Michiya Natori; Shiro Nozawa

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O. Kato

University of California

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K. Kato

Heidelberg University

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Daniel Bodri

Autonomous University of Barcelona

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