Publications by authors named "Kazuki Ohata"

Article Synopsis
  • The study investigated if hCG levels measured 10 days after a cleaved embryo transfer can help predict pregnancy and delivery results.
  • It analyzed data from 5,840 embryo transfer cycles, finding that the mean hCG level was 24.8 mIU/mL, with clinical pregnancy and live birth rates of 29.6% and 23.4%, respectively.
  • Key findings indicate maternal age and hCG levels significantly correlate with pregnancy outcomes, while low hCG levels may be linked to certain pregnancy complications but do not influence delivery outcomes.
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This study aimed to examine the viability of human blastocysts after warming with fatty acids (FAs) using an in vitro outgrowth model and to assess pregnancy outcomes after a single vitrified-warmed blastocyst transfer (SVBT). For the experimental study, we used 446 discarded vitrified human blastocysts donated for research purposes by consenting couples. The blastocysts were warmed using FA-supplemented (FA group) or non-FA-supplemented (control group) solutions.

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Purpose: The present study aimed to examine the correlations of the time interval from trophectoderm (TE) biopsy to vitrification with the blastocyst survival rate and blastocyst outgrowth ability.

Methods: A total of 1,202 mouse blastocysts were randomly divided into control (non-biopsy) and TE biopsy groups. The biopsied blastocysts were vitrified at various time points.

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Research Question: Does fatty acid supplementation in vitrification and warming media influence developmental competence in oocytes after vitrification and warming?

Design: Mouse oocytes and four-cell embryos were vitrified and warmed with solutions supplemented with fatty acid and cultured to the blastocyst stage. To study lipid metabolism after vitrification, quantitative real-time polymerase chain reaction was used to analyse the expression of genes related to beta oxidation in mouse embryos vitrified and warmed with or without fatty acids. The effects of fatty acid supplementation in the warming solutions on the developmental competence of bovine and human embryos were analysed.

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Research Question: What is the gene expression pattern of prolactin receptor (PRLR) in human pre-implantation embryos and what are its functions during the embryonic development and adhesion process?

Design: A total of 405 discarded human vitrified oocytes and embryos donated for research by consenting couples were used in this study. The oocytes and embryos were used to analyse PRLR expression and to evaluate the influence of prolactin (PRL) supplementation in the embryo culture medium on embryo developmental competence and viability. The rates of blastocyst development and adhesion, outgrowth area, cytoskeletal reorganization and nascent adhesion formation were compared between groups.

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Study Question: Do perturbations of embryo morphogenesis at compaction affect blastocyst development and clinical outcomes in assisted reproduction cycles?

Summary Answer: Cell exclusion and extrusion, i.e. cell disposal occurring respectively before or during morula compaction, affect blastocyst yield and quality, as well as rates of pregnancy and live birth.

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Background: Blastomere movement (BMov) occurs after the first cell division in human embryos. This movement has been suggested as a prognostic parameter for pregnancy outcome prediction following cleavage-stage embryo transfer. However, the effect of BMov on preimplantation development and pregnancy outcome after blastocyst transfer remains unclear.

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Research Question: What is the incidence, origin and clinical significance of blastomere movement after the first cell division in the human embryo?

Design: A total of 1096 embryos, cultured in the EmbryoScope+ ® time-lapse system and subjected to a single fresh cleaved embryo transfer, were retrospectively analysed. Type and duration of blastomere movement (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov during the 2-cell stage [dBMov/(t3-t2)] was calculated. Morphological evaluation of embryos was performed by referring to the size of the blastomere and fragmentation after first division in addition to Veeck's criteria on Day 2.

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