Dynamic changes in mitochondrial distribution in human oocytes during meiotic maturation.

Purpose: The change of mitochondrial distribution in human oocytes during meiotic maturation was assessed using 223 human oocytes donated from patients undergoing fertility treatment between June 2013 and February 2016.

Methods: Live cell images of fluorescence-labelled mitochondria in human oocytes were analysed to investigate dynamic changes in mitochondrial distribution during meiotic maturation using a confocal microscope combined with an incubator in the presence or absence of colchicine and cytochalasin B, inhibitors for tubulin and actin filament, respectively. Subcellular distribution of mitochondria in human oocytes was also assessed at various stages using a transmission electron microscope (TEM).

Good thermally conducting material supports follicle morphologies of porcine ovaries cryopreserved with ultrarapid vitrification.

Effects of supporting materials during vitrification procedure on the morphologies of preantral follicles of pig ovaries were assessed. Ovarian cortical sections of prepubertal pigs were randomly allocated to 5 groups. The sections were vitrified ultrarapidly with 5 different vitrification devices.

Growth retardation in human blastocysts increases the incidence of abnormal spindles and decreases implantation potential after vitrification.

Study Question: Does the human embryo growth rate affect the outcome of vitrified-warmed blastocyst transfer?

Summary Answer: Following vitrification, the incidence of abnormal spindle morphology was increased and the implantation competence was decreased in growth-retarded embryos compared with normally developing embryos.

What Is Known Already: Various types of spindle abnormality occur in human cleavage- and blastocyst-stage embryos. However, the incidence of abnormal spindle morphology in growth-retarded blastocysts is not known.

A closed system supports the developmental competence of human embryos after vitrification : Closed vitrification of human embryos.

Purpose: Closed-system vitrification may enable the risk of contamination to be minimised. We performed three studies to compare the developmental competence of human embryos vitrified using either a closed vitrification system (CVS; Rapid-i®) or an open vitrification system (OVS; Cryo-top®).

Methods: The first study was performed in vitro using 66 zygotes previously vitrified at pronuclear stage.

Developmental assessment of human vitrified-warmed blastocysts based on oxygen consumption.

Background: In this study, we aimed to develop a model for embryo selection based on oxygen consumption following cryopreservation, the relationship between the developmental competence of blastocysts and their oxygen consumption was assessed.

Methods: Oxygen consumption of vitrified-warmed human blastocysts was measured at 0, 1.5, 3, 4.