Correlation between female pronuclear/cytoplasmic ratio and number of chromosomes in mouse zygotic stage: implications for aneuploidy assessment in ART.

Purpose: The objective of this study was to investigate the correlation between the pronuclear/cytoplasmic (PN/C) ratio and the number of chromosomes in mouse zygotes to understand the implications of pronuclear size regulation in early embryonic development.

Methods: A combination of enucleation and aggregated chromosomes/chromatin (AC) transfer was utilized to create oocytes with varying numbers of chromosomes. Time-lapse imaging and immunofluorescence staining were employed to analyze pronuclear dynamics and chromosomal configurations.

The formation of aggregated chromatin/chromosomes in mouse oocytes treated with high concentration of IBMX as a model for a chromosome transfer in human.

The presence of cyclic adenosine monophosphate (cAMP) has been considered to be a fundamental factor in ensuring meiotic arrest prior to ovulation. cAMP is regarded as a key molecule in the regulation of oocyte maturation. However, it has been reported that increased levels of intracellular cAMP can result in abnormal cytokinesis, with some MI oocytes leading to symmetrically cleaved 2-cell MII oocytes.

Insecticidal activity against rice pest of oxazosulfyl, a novel sulfyl insecticide.

The development and commercialization of new chemical classes of insecticides are important for efficient crop protection, particularly for combatting insecticide resistance and providing sustainable agricultural production. This study reports on oxazosulfyl, a novel "sulfyl" class of insecticide, against a wide range of insect pests of rice. In the laboratory assay, oxazosulfyl showed insecticidal activity against all developmental stages of the brown planthopper (Stål).

Focusing on the accumulation of chromatin/chromosomes around nucleoli and optimizing the timing of ICSI to facilitate the rescue in vitro maturation of denuded GV stage oocytes.

Purpose: This study aims to achieve the methodological improvement of rescue IVM by predicting germinal vesicle breakdown (GVBD) and optimizing the timing of ICSI.

Methods: Time lapse analysis was performed retrospectively to evaluated the relationship between the presence of AC around the nucleoli and GVBD. To find the optimal timing of ICSI, the time from the initiation of the first polar body extrusion to ICSI were measured, and the rates of fertilization at each point were calculated.

Chromatin Morphology in Human Germinal Vesicle Oocytes and Their Competence to Mature in Stimulated Cycles.

The search for simple morphological predictors of oocyte quality is an important task for assisted reproduction technologies (ARTs). One such predictor may be the morphology of the oocyte nucleus, called the germinal vesicle (GV), including the level of chromatin aggregation around the atypical nucleolus (ANu)-a peculiar nuclear organelle, formerly referred to as the nucleolus-like body. A prospective cohort study allowed distinguishing three classes of GV oocytes among 135 oocytes retrieved from 64 patients: with a non-surrounded ANu and rare chromatin blocks in the nucleoplasm (Class A), with a complete peri-ANu heterochromatic rim assembling all chromatin (Class C), and intermediate variants (Class B).

Are tri-pronuclear embryos that show two normal-sized pronuclei and additional smaller pronuclei useful for embryo transfer?

Purpose: This study aimed to analyze whether tripronuclear (3PN) zygotes, with two normal-sized PNs and an additional smaller PN (2.1PN), can be used for embryo transfer.

Methods: A retrospective embryo cohort study was conducted on 695 patients who underwent intracytoplasmic sperm injection treatment.

The effect of betaine for mouse sperm cryopreservation.

Sperm cryopreservation is an effective method of preserving male fertility in humans, as well as domestic and experimental animals. However, various factors such as ice crystal formation, osmotic stress, and oxidative stress, negatively influence the motility and viability of post-thawed spermatozoa. Betaine, which works as an osmoprotectant is known to work as a nontoxic cryoprotectant.

A novel system based on artificial intelligence for predicting blastocyst viability and visualizing the explanation.

Purpose: The purpose of the study was to invent and evaluate the novel artificial intelligence (AI) system named Fertility image Testing Through Embryo (FiTTE) for predicting blastocyst viability and visualizing the explanations via gradient-based localization.

Methods: The authors retrospectively analyzed 19 342 static blastocyst images with related inspection histories from 9961 infertile patients who underwent in vitro fertilization. Among these data, 17 984 cycles of single-blastocyst transfer were used for training, and data from 1358 cycles were used for testing purposes.

Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization.

Background: Although rescue intracytoplasmic sperm injection (r-ICSI) is extensively used worldwide, the indication of r-ICSI and its optimal timing remains obscure. This study aimed to assess the outcomes of r-ICSI following in vitro fertilization in different timings when fertilization is confirmed.

Methods: This study included 5,156 cycles (47,785 eggs).

Clinical outcome of intrauterine infusion of platelet-rich plasma in patients with recurrent implantation failure.

Purpose: This study aimed to evaluate the effectiveness of intrauterine infusion of platelet-rich plasma (PRP) before embryo transfer (ET) in recurrent implantation failure (RIF) cases.

Methods: The authors retrospectively analyzed 54 ET cycles involving frozen and thawed high-quality blastocysts after intrauterine PRP infusion between September 2019 and November 2020. All patients had a history of at least two times of implantation failure on ET.

Developmental trajectory of monopronucleated zygotes after in vitro fertilization when they include both male and female genomes.

Objective: To examine the cause of monopronucleated zygote (1PN) formation that includes both maternal and paternal genomes.

Design: Retrospective cohort study.

Setting: Private fertility clinic.

Nuclear-to-cytoplasmic ratios of 1PN and 2PN zygotes after fertilization of mouse oocytes.

Numerous studies have reported comparisons of the nuclear-to-cytoplasmic (NC) ratio during mitosis. However, little information is known about how the pronuclear size is regulated and determined at the end of meiosis II in mammalian zygotes. The present study aims to analyze the NC ratio of female and male pronuclei, and also to compare the size of single pronuclei using photographs that were obtained during experiments to create chimeric hermaphrodites from 2-cell oocytes.

The Thickness and Density of the Ovarian Tunica Albuginea Increases with Age in Transgender Patients.

It is known that the extracellular matrix structure and composition changes with aging in many organs. Despite this, knowledge on how does the extracellular part of the ovary change with increasing age in women and how those changes might be related to women's loss of fertility is still lacking. For this, we propose that recurrent injury and repair events on the outermost layers of the ovary due to ovulation are partly responsible for those changes women experience with aging.

The inclusion of blastomeres into the inner cell mass in early-stage human embryos depends on the sequence of cell cleavages during the fourth division.

The fate of the ICM in humans is still unknown, due to the ethical difficulties surrounding experimentation in this field. In this study we have explored the existing time-lapse recording data of embryos in the early stages of development, taking advantage of the large refractile bodies (RBs) within blastomeres as cellular markers. Our study found that the cellular composition of the ICM in humans is largely determined at the time of the fourth division and blastomeres which cleave first to fourth, during the fourth division from 8 cells to 16 cells, have the potential to be incorporated in the ICM.

Predictive factors influencing pregnancy rate in frozen embryo transfer.

Purpose: To evaluate the outcomes of embryo transfer (ET) and to identify the parameters influencing pregnancy outcomes.

Methods: This study included 938 ET cycles involving single frozen and thawed good-quality blastocyst (Gardner grade ≥3BB) between August 2017 and January 2018. The significance of several parameters including endometrial thickness, position of the transferred air bubble, self-evaluation score by physicians, and uterus direction at ET as predictors of clinical pregnancy was evaluated using univariate and multivariate analyses.

Clinical outcomes of MII oocytes with refractile bodies in patients undergoing ICSI and single frozen embryo transfer.

Purpose: This study aimed to analyze whether the presence of refractile bodies (RFs) negatively affects fertilization, embryo development, and/or implantation rates following intracytoplasmic sperm injection (ICSI).

Methods: This retrospective embryo cohort study involved a total of 272 patients undergoing ICSI treatment of blastocyst cryopreservation.

Results: In the study, no significant differences were found regarding 2PN formation rates between RF(+) (76.

Noninvasive embryo selection: kinetic analysis of female and male pronuclear development to predict embryo quality and potential to produce live birth.

Objective: To evaluate a noninvasive method of examining euploid embryos, focusing on kinetic analyses, from second polar body extrusion to pronuclear membrane breakdown (PNMBD).

Design: Retrospective embryo cohort study.

Setting: Private IVF clinic.

A higher incidence of smooth endoplasmic reticulum clusters with aromatase inhibitors.

Purpose: This study aimed to analyze whether a regimen of aromatase inhibitor (AI) could reduce the occurrence of smooth endoplasmic reticulum clusters (sERCs) in oocytes.

Methods: The AI and the clomiphene citrate (CC) regimens were compared, regarding the sERC (+) rates and the serum estradiol and progesterone levels on the date of hCG administration, and the duration of AI, CC, and hMG administration.

Results: The occurrence of sERCs in oocytes from patients treated with AI was significantly higher than that in oocytes from those treated with CC.

A higher incidence of cleavage failure in oocytes containing smooth endoplasmic reticulum clusters.

Purpose: In human oocytes, sERCs are one of the dysmorphic phenotypes that have been reported. Significantly reduced pregnancy rates and a comparatively higher number of abnormities in live births appear to be associated with the presence of sERCs in oocytes. However, some reports have shown that healthy babies can be born, without any reduced pregnancy rates, from oocytes observed to contain sERCs.

Retrospective comparative study of the factors affecting birthweights in frozen-thawed embryo transfer, compared to fresh embryo transfer.

Aim: Several studies have indicated that the cause of the increased birthweight of frozen-thawed embryos was associated with assisted reproductive technology (ART) procedures, such as cryopreservation. In the present study, the mean birthweight of singletons was compared between the ovulatory and hormone replacement therapy (HRT) cycles in order to investigate the primary factor that leads to higher birthweights from frozen-thawed embryo transfer (FET).

Methods: This retrospective study was carried out from January 2011 to December 2014 on 2738 singletons who were born at 37-41 weeks' gestation, following ART in a single facility.

Potential of zygotes to produce live births can be identified by the size of the male and female pronuclei just before their membranes break down.

Aim: To determine whether there are differences in size between the male and female pronuclei immediately before the pronuclear membrane breakdown (PNMBD) and to evaluate whether pronuclear size differences influence normal birth rates.

Methods: Time-lapse photography was used to measure the size of each pronucleus, while the outcome of 71 frozen-thawed single blastocyst transfers in patients receiving hormone therapy was analyzed retrospectively. The pronuclear measurements were made 4 hours before the PNMBD, corresponding to 16-20 hours after insemination or intracytoplasmic sperm injection, and immediately before the PNMBD.

Grade and looseness of the inner cell mass may lead to the development of monochorionic diamniotic twins.

Objective: To examine the relationship between the inner cell mass (ICM) grade and its morphological configuration on the occurrence of monochorionic diamniotic (M-D) twinning.

Design: Retrospective embryo cohort study.

Setting: Private IVF clinic.

Detection and quantification of male-specific fetal DNA in the serum of pregnant cynomolgus monkeys (Macaca fascicularis).

Because of their developmental similarities to humans, nonhuman primates are often used as a model to study fetal development for potential clinical applications in humans. The detection of fetal DNA in maternal plasma or serum offers a source of fetal genetic material for prenatal diagnosis. However, no such data have been reported for cynomolgus monkeys (Macaca fascicularis), an important model in biomedical research.

Aggregated chromosomes transfer in human oocytes.

Germinal-vesicle (GV) transfer, spindle-chromosome complex transfer in metaphase-II oocytes and two pronuclei transfer have been evaluated as possible treatments for patients who have mitochondrial diseases. However, GV transfers often lead to heteroplasmy while the other two methods are frequently associated with aneuploidy. The present study used a new method based on the transfer of aggregated chromosomes, which occurs in human oocytes, before the metaphase spindle is established.