Assessment of embryologist sufficiency and associated regional disparities in Japanese assisted reproduction facilities using nationwide survey data (IZANAMI project).

AIMS: This study aims to comprehensively examine the employment and practices of embryologists in Japan's assisted reproductive technology (ART) laboratories, focusing on the impact of various factors such as ART cycle numbers, add-ons, and regional differences. Additionally, it seeks to assess the extent to which Japanese ART facilities meet international minimum standards set by the American Society for Reproductive Medicine (ASRM). METHODS: A survey was conducted from December 2021 to February 2022 among 621 ART facilities in Japan. The study categorized facilities into five ART cycle groups and compared the number of embryologists across these groups. It also examined the correlation between the number of embryologists, ART cycles, add-ons, and regional differences. Data were analyzed using linear regression and multiple linear regression analyses. RESULTS: The study's findings revealed a significant correlation between the total number of embryologists at each facility and the ART cycles. Notably, there were significant differences in the number of embryologists across all ART cycle categories. Of the 435 facilities, only 44.6% met the ASRM minimum embryologist staffing requirement. The regression analysis further highlighted the significance of ART cycles and preimplantation genetic testing for aneuploidies as factors. Moreover, the number of embryologists stationed at urban facilities was significantly higher than at nonurban facilities, indicating a potential regional disparity. CONCLUSION: In Japan, it was first found that more than 50% of ART facilities do not have sufficient embryologists in place relative to the number of ART cycles. Furthermore, the add-ons and regional differences affect the placement of embryologists.

Variation in diagnostic methods, criteria, and treatment for chronic endometritis: A nationwide survey in Japan.

AIM: To investigate variation in the diagnosis and treatment of chronic endometritis (CE) at the national level in Japan. METHODS: We performed a nationwide survey targeting all assisted reproductive technology (ART) facilities across Japan between 2021 and 2022. Diagnostic methods, criteria, and first- and second-line treatment protocols for CE were collected via a questionnaire. RESULTS: Among 616 ART facilities, 437 responded to the survey (response rate: 70.9%) of which 339 (77.6%) implemented diagnosis and treatment of CE. In the diagnosis of CE, 214 (63.1%) facilities used CD138 immunohistochemical staining of endometrial tissue, while hysteroscopy was the most frequently used as an adjunct diagnostic method (241 facilities, 71.1%). The most frequent cutoff value of CD138-positive cells for diagnosing CE was 3-5 cells/20 high-power fields (50%), but 7.9% (17 facilities) and 5.1% (11 facilities) used cutoff values of 1 and 2 cells, respectively. The most common first- and second-line treatment methods were doxycycline (210 facilities, 61.9%) and ciprofloxacin + metronidazole (164 facilities, 48.0%), respectively. CONCLUSIONS: There is considerable variation in the number of CD138-positive cells used for diagnosing CE. Establishing unified diagnostic criteria and therapeutic methods for CE is essential to provide standardized medicine for CE at the national level.

Fact-finding survey on assisted reproductive technology in Japan.

AIMS: In anticipation of the future development of assisted reproductive technology (ART) and to smoothly introduce new technology, it is necessary to understand the current staffing status of the medical system and the current state of treatment, as well as the status of in vitro fertilization add-ons, where the need for insurance coverage is currently a matter of debate. METHODS: ART facilities in Japan were surveyed (437 valid responses, response rate: 71%). Current staffing status of the medical system, implementation rates of ART, add-on treatments, and medical supplies were investigated. RESULTS: Despite the abundance of embryologists, nurses, and obstetricians and gynecologists in facilities, the majority of facilities lacked counselors, anesthesiologists, and other essential medical professionals. Conventional ovarian stimulation was widely adopted (median 120 [interquartile range 60-300] cycles), followed by mild ovarian simulation (60 [30-200]). Additionally, freeze-thaw embryo transfer cycles (300 [120-750]) were performed more frequently than fresh embryo transfer cycles (30 [30-60]). Among the add-ons, assisted hatching (85.1%), chronic endometritis examination (77.2%) and treatment (76.9%), artificial oocyte activation (67.3%), endometrial receptivity analysis (64.2%), and endometrial microbiome analysis (58.9%) were relatively widely employed. CONCLUSIONS: The implementation of frozen-thawed embryo transfer cycles, freeze-all strategies, and add-on treatments have become popular and widely accepted despite the lack of robust evidence regarding their safety and efficacy.

An approach for live imaging of first cleavage in mouse embryos using fluorescent chemical probes for DNA, microtubules, and microfilaments.

Purpose: Dynamic morphological changes in the chromosome and cytoskeleton occur in mammals and humans during early embryonic development, and abnormalities such as embryonic chromosomal aneuploidy occur when development does not proceed normally. Visualization of the intracellular organelles and cytoskeleton allows elucidation of the development of early mammalian embryos. The behavior of the DNA and cytoskeleton in early mammalian embryos has conventionally been observed by injecting target molecule mRNAs, incorporating a fluorescent substance-expressing gene, into embryos. In this study, we visualized the chronological behavior of male and female chromosome condensation in mouse embryos, beginning in the two-pronuclear zygote, through the first division to the two-cell stage, using fluorescent chemical probes to visualize the behavior of DNA, microtubules, and microfilaments. Method: Mouse two-pronuclear stage embryo were immersed in medium containing fluorescent chemical probes to visualize DNA, microtubules, and microfilaments. Observation was performed with a confocal microscope. Results: This method allowed us to observe how chromosome segregation errors in first somatic cell divisions in mouse embryos and enabled dynamic analysis of a phenomenon called lagging chromosomes. Conclusions: By applying this method, we can observe any stage of embryonic development, which may provide new insights into embryonic development in other mammals.

Effects of localisation of uterine adenomyosis on outcome of in vitro fertilisation/intracytoplasmic sperm injection fresh and frozen-thawed embryo transfer cycles: a multicentre retrospective cohort study.

BACKGROUND: Uterine adenomyosis is a benign disease, common among women in their 40 and 50 s, characterised by ectopic endometrial tissue in the uterine myometrial layer. Adenomyosis causes infertility and has a negative effect on the outcomes of in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) embryo transfer (ET) cycles. It has also been reported to have different characteristics depending on the adenomyotic lesion localisation. The effect of its localisation on IVF/ICSI-ET outcomes is unclear. This study aimed to investigate whether adenomyotic lesion localisation, assessed using magnetic resonance imaging (MRI), was associated with outcomes of IVF/ICSI-ET cycles. METHODS: This multicentre, joint, retrospective cohort study analysed the medical records of 67 infertile patients with adenomyosis who underwent IVF/ICSI with fresh and frozen-thawed ET at five participating facilities from January 2012 to December 2016 and for whom MRI data were available. Fifteen patients were excluded; therefore, the MRI data of 52 patients were evaluated by two radiologists. We assessed the localisation of and classified adenomyotic lesions into advanced (invades the full thickness of the uterine myometrium), extrinsic (localised on the serosal side), and intrinsic (localised on the endometrial side) subtypes. RESULTS: There were 40 advanced, nine extrinsic, and three intrinsic cases, and the outcomes of 100, 27, and nine ET cycles, respectively, were analysed. Pregnancy loss/clinical pregnancy and live birth rates of the advanced, extrinsic, and intrinsic groups were 64 % (16/25) and 9 % (9/100), 33.3 % (3/9) and 22.2 % (6/27), and 50 % (1/2) and 11.1 % (1/9), respectively. A logistic regression analysis adjusted for age, prior miscarriage, and body mass index showed that the extrinsic group had fewer pregnancy losses (odds ratio 0.06; 95 % confidence interval [CI]: 0.00-0.54, p = 0.026) and more live births (odds ratio 6.05; 95 % CI: 1.41-29.65, p = 0.018) than the advanced group. CONCLUSIONS: Adenomyotic lesions exert different effects on IVF/ICSI-ET outcomes. Thus, MRI assessments of adenomyosis in infertile patients are beneficial. Establishment of treatment plans based on adenomyotic lesion localisation should be considered.

An extragonadal yolk sac tumor presumed to be of postmeiotic germ cell origin by genetic zygosity analysis via single nucleotide polymorphism array.

An extragonadal yolk sac tumor (YST) is a rare malignant germ cell tumor that usually occurs in childhood. The pathogenesis of extragonadal YST remains largely unknown, especially with regards to its cell of origin. Herein, we report a case of extragonadal YST arising in the uterine round ligament. A 31-year-old Japanese woman, para 2, underwent partial resection of a left-sided, 5-cm, solid inguinal mass. Intraoperative findings showed enlargement of the uterine round ligament in the inguinal canal. Pathological evaluation diagnosed the mass as YST with a mature teratoma (MT) component. The preoperative α-fetoprotein level was markedly elevated, at 24 790 ng/mL. Postoperative magnetic resonance imaging revealed a right ovarian MT and a 3-cm mass remaining in the left lower abdominal wall. The patient underwent total abdominal hysterectomy, bilateral adnexectomy, and left inguinal mass resection. We sampled three frozen tissues (YST, right ovarian MT, and left normal ovary) and performed a single nucleotide polymorphism (SNP) array. Pathological evaluation revealed remnant extragonadal YST in the left inguinal region. The SNP array demonstrated a completely homozygous YST genotype. Copy number variations were gains of 1p, 1q, 2p, 3p, 7p, 8p, 10q, 14q, 18p, 20q, Xp, and Xq and losses of 12q, 20p, and Xq. The right ovarian MT and left normal ovary were partially homozygous and heterozygous, respectively. The evidence suggests that this neoplasm is presumed to be a postmeiotic germ cell origin.

Consistency between chromosomal status analysis of biopsied human blastocyst trophectoderm cells and whole blastocyst cells.

PURPOSE: This study investigated the consistency between results of preimplantation genetic testing for aneuploidy performed on trophectoderm (TE) cells and remaining blastocyst cells. METHODS: TE biopsy was performed on 29 surplus cryopreserved human blastocysts. Biopsy samples and remaining blastocysts were processed using the VeriSeq PGS kit, and chromosomal statuses were compared by next-generation sequencing. RESULTS: Discordance was observed in the chromosomal status of 11 out of 29 blastocysts between the biopsied TE and remaining blastocysts. Concordance was observed in 11 of 12 blastocysts classified as euploid by TE biopsy and in 7 of 17 blastocysts classified as aneuploid. There was 100% concordance (7/7) in cases diagnosed as aneuploid with no mosaicism by TE biopsy. However, discordance was observed in all 10 cases showing mosaicism or partial chromosomal abnormality. CONCLUSION: Chromosomal status analysis based on TE biopsy does not accurately reflect the chromosomal status of the whole blastocyst. The chromosomal status is usually the same between the TE and remaining blastocyst cells in cases diagnosed as euploid or aneuploid with no mosaicism. However, mosaic blastocysts and those with other types of structural rearrangements have a higher risk of inconsistency, warranting caution during embryo selection.

Promoting fertility awareness and preconception health using a chatbot: a randomized controlled trial.

RESEARCH QUESTION: What are the effects of using a fertility education chatbot, i.e. automatic conversation programme, on knowledge, intentions to improve preconception behaviour and anxiety? DESIGN: A three-armed, randomized controlled trial was conducted using an online social research panel. Participants included 927 women aged 20-34 years who were randomly allocated to one of three groups: a fertility education chatbot (intervention group), a document about fertility and preconception health (control group 1) or a document about an irrelevant topic (control group 2). Participants' scores on the Cardiff Fertility Knowledge Scale and the State-Trait Anxiety Inventory, their intentions to optimize preconception behaviours, e.g. taking folic acid, and the free-text feedback provided by chatbot users were assessed. RESULTS: A repeated-measures analysis of variance showed significant fertility knowledge gains after the intervention in the intervention group (+9.1 points) and control group 1 (+14.9 points) but no significant change in control group 2 (+1.1 points). Post-test increases in the intentions to optimize behaviours were significantly higher in the intervention group than in control group 2, and were similar to those in control group 1. Post-test state anxiety scores were significantly lower in the intervention group than in control group 1 and control group 2. User feedbacks about the chatbot suggested technical limitations, e.g. low comprehension of users' words, and pros and cons of using the chatbot, e.g. convenient versus coldness. CONCLUSIONS: Providing fertility education using a chatbot improved fertility knowledge and intentions to optimize preconception behaviour without increasing anxiety, but the improvement in knowledge was small. Further technical development and exploration of personal affinity for technology is required.

Associations of environmental exposures to methylmercury and selenium with female infertility: A case-control study.

BACKGROUND: Methylmercury exposure is a common health risk resulting from daily fish intake. However, studies addressing the link between methylmercury and infertility are limited and also inconsistent. In addition, no previous epidemiological studies have accounted for the interaction between methylmercury and selenium. We aimed to investigate the association between environmental exposures to metals and female fertility. METHODS: This case-control study included 98 infertile women receiving fertility treatment (infertile group) and 43 female workers in their thirties (control group) who provided blood samples and returned a questionnaire on lifestyles and dietary characteristics. Blood levels of mercury, lead, cadmium, arsenic, manganese, zinc, and selenium were compared between the groups. Spearman correlation analyses between anti-Müllerian hormone and the metals were conducted. RESULTS: The mean selenium level in blood (±â€¯SD) and the selenium/mercury molar ratio were significantly lower in the infertile group (189 ±â€¯25 µg/L and 94.6 ±â€¯44.3, respectively) than in the control group (200 ±â€¯25 µg/L and 118.4 ±â€¯70.5). By contrast, blood mercury levels after adjusting for blood selenium and age were significantly higher in the infertile group than in the control group. Multiple logistic regression analyses with the adjustment for the other metals and potential confounders confirmed significant associations of infertility with elevated mercury and reduced selenium levels. No significant correlations were observed between anti-Müllerian hormone and metals. CONCLUSIONS: Methylmercury and selenium exposures appear to have adverse and protective effects on female fertility, respectively. This is the first report to suggest the antagonistic interaction between methylmercury and selenium in relation to human female fertility.

Oocyte collection and in vitro maturation after train transportation of human follicular fluid aspirated from resected non-stimulated ovaries of patients with endometrial adenocarcinoma.

PURPOSE: Immature human oocytes from resected ovaries can be used for research and fertility preservation, though it is unknown whether it is feasible to transport oocytes for these purposes. This study examined in vitro maturation (IVM) outcomes after the transportation of human follicular fluid (HFF) containing oocytes. METHODS: Fourteen patients with endometrial adenocarcinoma were enrolled. Oocytes obtained from the resected ovaries of seven patients were transported with HFF by railway (transportation group). Samples of HFF from the other seven patients were not transported, and IVM was performed promptly (non-transportation group). The results of oocyte retrieval and IVM were compared. RESULTS: The average ages in the transportation and non-transportation groups were 40.1 ± 2.0 and 39.6 ± 1.8 years, respectively, and the average numbers of collected oocytes were 8.1 ± 8.4 and 5.1 ± 5.1, respectively. There was a significant negative correlation between the number of collected oocytes and age. The proportions of oocytes that reached meiosis II (maturation rate) after IVM were 38.6% and 69.2% in the transportation and non-transportation groups, respectively (P = 0.013). CONCLUSION: In this preliminary study, the usefulness of the transportation of HFF was limited. Further studies on maintaining oocyte normality during transportation are necessary for becoming the effective method for research and clinical use.

Clinical characteristics of Lynch-like cases collaterally classified by Lynch syndrome identification strategy using universal screening in endometrial cancer.

OBJECTIVE: Lynch syndrome (LS), an autosomal-dominant inherited disorder, increases the risk for LS-associated cancers (LS-AC). Molecular LS assessment for all cases is referred to as universal screening (U/S) and is recommended for endometrial cancer (EC) and colorectal cancer. Lynch-like cases (LL) lack LS-pathogenic mutations despite being suspected as LS by U/S, but have been poorly investigated in EC. The aim of this study was to capture the features of LL in EC and to devise LL management in EC. METHODS: U/S, consisting of immunohistochemistry and reflex methylation analysis, was applied to 348 Asian ECs, and sporadic cancer (SC) cases were screened out. Genetic testing was offered to "suspected-LS" cases selected by U/S. The features of the LS, LL, and SC groups were recorded and compared. RESULTS: U/S screened 306 ECs as SC. The recurrence rates of suspected-LS and SC cases were 14.3% (6/42) and 26.5% (81/306), respectively. Of the 42 suspected-LS cases, 10 were identified as LS, 17 were classified as LL, and 15 did not undergo genetic testing. In the LS group, the frequency of personal history (50%) and family history (100%) of LS-AC were prominent. Of note, the prevalence of family history of LS-AC and gastric cancer was significantly higher in the LL group than in the SC group (76.5% vs. 38.6% and 47.1% vs. 25.2%, respectively). CONCLUSIONS: Herein, we report the features of LL classified by LS identification via U/S in Asian EC. LL should be candidates for tailored surveillance based on regionality and family history.

Preventive effect of human papillomavirus vaccination on the development of uterine cervical lesions in young Japanese women.

AIM: To examine the effect that human papillomavirus (HPV) vaccination has had in Akita Prefecture, by comparing cervical cytology results from women aged 20-24 years with or without HPV vaccination. METHODS: We examined cervical cytology results from 2425 subjects who underwent cervical cancer screening under the jurisdiction of the Akita Foundation for Healthcare between January 2014 and October 2016. We compared the prevalence of cytologic abnormalities among women aged 20-24 years with or without HPV vaccination. RESULTS: The rate of atypical squamous cells of undetermined significance (ASC-US) or worse was 0.242% (1/413) with HPV vaccination, and 2.04% (41/2012) without HPV vaccination. Overall, the prevalence of abnormal cytology results was significantly lower in women aged 20-24 years who had received an HPV vaccination than in those who had not (P = 0.011). The reduction in the rate of abnormal cervical cytology results by HPV vaccination was 88.1%. CONCLUSION: Within a 4-year-5-year period following vaccination, women aged 20-24 years who received an HPV vaccination had significantly lower rates of abnormal cervical cytology results than those who did not receive the vaccine.

In vitro maturation of human immature oocytes for fertility preservation and research material.

Aim: In recent years, the importance of fertility preservation (FP) has increased. In vitro maturation (IVM), an important technique in FP, has started to be used in the clinic, but controversies persist regarding this technique. Here, a survey of IVM for FP is provided. Methods: Based on a literature review, the applications of FP, methods of FP, IVM of oocytes that had been collected in vivo and ex vivo, maturation of oocytes after IVM for FP, cryopreservation of oocytes for FP, explanation of the procedures to patients, and recent research on FP using IVM were investigated. Results: Although IVM for FP remains controversial, the application of FP is expected to expand. Depending on the age and disease status of the patient, various methods of oocyte collection and ovarian stimulation, as well as various needle types and aspiration pressures, have been reported. The maturation rate of IVM in FP ranges widely and requires optimization in the future. In regard to cryopreservation for matured oocytes, the vitrification method is currently recommended. Conclusion: Regarding FP for patients with cancer, the treatment of cancer is prioritized; thus, the time and use of medicines are often constrained. As several key points regarding IVM remain unclear, well-designed and specific counseling for patients is necessary.

Time-lapse monitoring reveals that vitrification increases the frequency of contraction during the pre-hatching stage in mouse embryos.

Contraction during the blastocyst stage is observed during embryonic development of various mammals, including humans, but the physiological role of this process is not well understood. Using time-lapse monitoring (TLM), we studied the influence of vitrification and contractions on embryonic development in mice. Mouse embryos were cultured at the 2-cell stage. At the 8-cell stage, embryos were randomly divided into a fresh group (FG) and vitrified group (VG) and observed for up to 144 h. Strong contractions (i.e., contractions causing a decrease in volume of more than 20% and expansion of the perivitelline space) occurred significantly more often in unhatched embryos than hatching embryos in both groups. Regarding hatching embryos, contractions in the pre-hatching stage were significantly more frequent in the VG than the FG. Furthermore, mRNA expression levels of genes related to contractions were determined at three time points, the 8-cell stage, early blastocyst stage, and 20 h after blastocoel formation, with quantitative reverse transcription-polymerase chain reaction. There was no significant difference in Hspa1a expression between the FG and VG, but Hspa1a overexpression was observed just after thawing and tended to decrease gradually thereafter in some blastocysts. Furthermore, in the VG, Atp1a1 tended to show higher expression in the strong contraction group than in the weak contraction group. Overall, vitrification is an excellent method for cryopreservation but could increase contractions in the pre-hatching stage and may increase energy demands of the embryo. Observation of contraction by TLM may improve the evaluation of embryo quality.

CRP 1846C>T Genetic Polymorphism Is Associated with Lymph Node Metastasis and/or Severe Lymphatic Invasion in Endometrial Cancer.

Endometrial cancer (EC) rates are rising in Japan. Lymph node (LN) metastasis is an important prognostic factor in EC, and its risk is increased with higher tumor grade, deep myometrial invasion, larger tumor size, and lymphovascular space invasion (LVSI). Current methodologies to assess these factors are unreliable. We previously showed the association between C-reactive protein (CRP) 1846C>T (rs1205) polymorphism and LN metastasis in esophageal, non-small cell lung, and breast cancers. The CRP gene is located on chromosome 1q21-q23, and the polymorphism in the noncoding region (1846C>T) of this gene decreases serum CRP levels. We investigated the relationship between CRP 1846C>T genetic polymorphism and LN metastasis or LVSI in 130 EC patients using polymerase chain reaction-restriction fragment length polymorphism. The CRP 1846C/T genotype was C/C in 11 patients, C/T in 58 patients and T/T in 61 patients. The patients were divided into two groups based on their CRP 1846 genotypes: "C/C" and "C/T + T/T". Nine (7%) and 18 (13%) patients, all with the polymorphism, had LN metastasis and moderate or prominent lymphatic invasion, respectively. LN metastasis and/or severe lymphatic invasion were observed in the C/T + T/T group, while patients with the C/C genotype had no LN metastases or severe lymphatic invasion. Univariate and multivariate logistic regression models revealed that the C/T + T/T patients had a significant likelihood of developing LN metastasis and/or severe lymphatic invasion. Our results suggest that CRP genetic polymorphism is a novel risk predictor of LN metastasis and/or lymphatic invasion in EC.

Impact of adjuvant chemotherapy for stage I ovarian carcinoma with intraoperative tumor capsule rupture.

AIM: Adjuvant chemotherapy is generally recommended for early stage epithelial ovarian cancer. However, it remains uncertain which histological subtypes and substages of stage I disease should receive adjuvant chemotherapy. The objective of this study is to determine the impact of chemotherapy among stage I epithelial ovarian cancer. MATERIAL AND METHODS: Of the 267 patients with stage I epithelial ovarian cancer analyzed in this study, 152 patients received adjuvant chemotherapy (AC-positive group) and 115 patients did not (AC-negative group). Survival analysis was retrospectively performed to determine the effectiveness of adjuvant chemotherapy in stage I epithelial ovarian cancer patients. RESULTS: Recurrence was observed in 14 patients in the AC-negative group and 20 patients in the AC-positive group. There were no statistically significant differences in disease-free survival (DFS) and overall survival between the two groups. In stage IA and IB patients, there was no statistically significant difference in DFS and overall survival based on adjuvant chemotherapy status. However, in patients with intraoperative tumor capsule rupture, the AC-positive group had significantly better DFS than the AC-negative group (P = 0.01). Patients with clear cell carcinoma who received adjuvant chemotherapy had better DFS than patients who did not (P = 0.004). CONCLUSIONS: Adjuvant chemotherapy may not be necessary for patients with stage IA or IB epithelial ovarian cancer, but may be beneficial for clear cell carcinoma patients with intraoperative tumor rupture.

Dysfunction in gap junction intercellular communication induces aberrant behavior of the inner cell mass and frequent collapses of expanded blastocysts in mouse embryos.

PURPOSE: We investigated the role of gap junctions (GJs) in embryological differentiation, and observed the morphological behavior of the inner cell mass (ICM) by time-lapse movie observation (TLM) with gap junction inhibitors (GJis). METHODS: ICR mouse embryos were exposed to two types of GJis in CZB medium: oleamide (0 to 50 µM) and 1-heptanol (0 to 10 mM). We compared the rate of blastocyst formation at embryonic day 4.5 (E4.5) with E5.5. We also observed and evaluated the times from the second cleavage to each embryonic developing stage by TLM. We investigated embryonic distribution of DNA, Nanog protein, and Connexin 43 protein with immunofluorescent staining. RESULTS: In the comparison of E4.5 with E5.5, inhibition of gap junction intercellular communication (GJIC) delayed embryonic blastocyst formation. The times from the second cleavage to blastocyst formation were significantly extended in the GJi-treated embryos (control vs with oleamide, 2224 ± 179 min vs 2354 ± 278 min, p = 0.013). Morphological differences were traced in control versus GJi-treated embryos until the hatching stage. Oleamide induced frequent severe collapses of expanded blastocysts (77.4 % versus 26.3 %, p = 0.0001) and aberrant ICM divisions connected to sticky strands (74.3 % versus 5.3 %, p = 0.0001). Immunofluorescent staining indicated Nanog-positive cells were distributed in each divided ICM. CONCLUSIONS: GJIC plays an important role in blastocyst formation, collapses of expanded blastocysts, and the ICM construction in mouse embryos.

Shape of the first mitotic spindles impacts multinucleation in human embryos.

During human embryonic development, early cleavage-stage embryos are more susceptible to errors. Studies have shown that many problems occur during the first mitosis, such as direct cleavage, chromosome segregation errors, and multinucleation. However, the mechanisms whereby these errors occur during the first mitosis in human embryos remain unknown. To clarify this aspect, in the present study, we image discarded living human two-pronuclear stage zygotes using fluorescent labeling and confocal microscopy without microinjection of DNA or mRNA and investigate the association between spindle shape and nuclear abnormality during the first mitosis. We observe that the first mitotic spindles vary, and low-aspect-ratio-shaped spindles tend to lead to the formation of multiple nuclei at the 2-cell stage. Moreover, we observe defocusing poles in many of the first mitotic spindles, which are strongly associated with multinucleation. Additionally, we show that differences in the positions of the centrosomes cause spindle abnormality in the first mitosis. Furthermore, many multinuclei are modified to form mononuclei after the second mitosis because the occurrence of pole defocusing is firmly reduced. Our study will contribute markedly to research on the occurrence of mitotic errors during the early cleavage of human embryos.

Retrieval and in vitro maturation of human oocytes from ovaries removed during surgery for endometrial carcinoma: a novel strategy for human oocyte research.

PURPOSE: To collect human oocytes from ovaries removed as part of surgical treatment for endometrial carcinoma, and to induce in vitro maturation of such oocytes to obtain material for research on human ovarian aging. DESIGN: Prospective clinical study. SETTING: University Hospital. PATIENTS: Eight patients aged 35-44 years with a preoperative diagnosis of Stage I endometrial cancer agreed to participate in this project. INTERVENTIONS: Surgically removed ovaries were punctured; oocytes were collected from follicular fluid and matured in vitro. Immunofluorescent detection of microtubules and DNA labeling were performed after in vitro maturation. MAIN OUTCOME MEASURES: Number of oocytes collected and their in vitro maturation stage. RESULTS: In total, 87 oocytes were collected, 11 of which had completed metaphase II. Of the oocytes collected, 75 % were from three patients in their 30s, while the remaining 25 % were from five patients in their 40s. Several stages of oocytes were collected and the detection of microtubule arrangement and chromatin in various stages using fluorescence was possible. CONCLUSION: Material for research on human ovarian aging can be obtained from ovaries removed during surgery for endometrial cancer.