Yasuyuki Mio - Academia.edu (original) (raw)

Papers by Yasuyuki Mio

Journal of Assisted Reproduction and Genetics, 2019

Purpose To investigate the stability of osmolality in non-humidified and humidified incubators fo... more Purpose To investigate the stability of osmolality in non-humidified and humidified incubators for assisted reproductive technologies (ART). Methods Drops of three single-step culture media (media A, B, and C) were incubated for 5 or 6 days covered with four different mineral oils (oils A, B, C, and D) in non-humidified incubator A, non-humidified incubator B, or humidified incubator C to investigate the effects of incubator environment (humidification), drop volume, culture media, and mineral oil on the stability of osmolality in microdrops. Results A significant and linear increase was shown in the osmolality of 50-μL and 200-μL microdrops covered with mineral oil during 5 days incubation in non-humidified benchtop incubators. The maximum increase was 20 mOsm/kg, and the extent of the increase was affected by microdrop volume and possibly by the type of mineral oil used to cover the drops. In contrast, the osmolality of 50-μL and 200-μL microdrops did not change during 5 days incubation in a humidified benchtop incubator. Conclusions Mineral oil alone may not adequately prevent gradual changes in the osmolality of low-volume microdrops during extended in vitro culture of human embryos in non-humidified incubators. As a result, the osmolality may increase to high enough levels to stress some human embryos and adversely affect clinical outcomes. We therefore recommend that the stability of osmolality should be given more consideration to ensure optimal culture conditions for ART.

Journal of Ultrasound in Medicine, 2016

Journal of Mammalian Ova Research, 2011

Time-lapse cinematography(TLC)を用いてヒト胚盤胞期胚を観察した．体外培養時のヒト胚盤胞期胚では，胞胚腔の拡張と虚脱が頻繁に起っており，TLC 映像から，虚脱の機序... more Time-lapse cinematography(TLC)を用いてヒト胚盤胞期胚を観察した．体外培養時のヒト胚盤胞期胚では，胞胚腔の拡張と虚脱が頻繁に起っており，TLC 映像から，虚脱の機序は栄養膜細胞(trophectoderm; TE) の破綻であることが明らかとなった．また，内細胞塊(inner cell mass; ICM)が対側の TE と不規則に接着し，糸を引き合う現象(strand 現象)が初めて確認でき，この現象により，ICM が 2 分されると単一の TE 内に 2 個の ICM が形成され，これが，1 卵性双胎(monozygotic twin; MZT)の発生機序であることも明らかとなった．また，ヒト拡張胚盤胞が透明帯から脱出(hatching)する様式に 2 通り(inward，outward)が存在し，体外培養時には inward 様式が高率に認められたが，脱出にかかる所要時間は，有意に outward 様式が短く，生体内での生理的 hatching は outward 様式の可能性が考えられた．今回の TLC 解析結果から，ヒト胚の胚盤胞期までの体外培養延長は，種々の胚に対する負の影響を招いている可能性が示唆され，体外培養環境の改善，あるいは，体外培養期間の短縮等，再考を要すると考えられた．

Analysis of Physiological Process in Early Stage of Human Embryos after ICSI using Time-lapse Cinematography

Journal of Mammalian Ova Research, 2005

ABSTRACT

The Tohoku Journal of Experimental Medicine, 1991

To illustrate the influence of kallikrein on the hypoosmotic swelling test, 84 human semen sample... more To illustrate the influence of kallikrein on the hypoosmotic swelling test, 84 human semen samples were classified into 4 groups : normospermia (n = 34, group A), oligospermia (n =18, group B), asthenospermia (n = 8, group C), and oligoasthenospermia (n = 24, group D). Two aliquots of 0.45 ml were prepared from each specimen in all the groups : one was incubated for 3 hr in a glass tube containing kallikrein and the other was incubated without kallikrein (control). Quantitative and qualitative assessment of sperm motility and the hypoosmotic swelling test (HOST) were subsequently performed in each pair of samples. Percentage of motile spermatozoa, speed of forward progression of motile spermatozoa and the percentage of swollen sperm were significantly lower in the control samples than in samples treated with kallikrein in all the groups. Kallikrein was also proved effective in increasing the outcome of the HOST, the percentage of motile spermatozoa and the speed of forward progression of washed spermatozoa received from normospermic men (n =15). It seems that kallikrein has a direct effect on sperm membrane and improves its properties and functions. kallikrein ; hypoosmotic swelling test

The Tohoku Journal of Experimental Medicine, 1992

Twenty semen samples were collected and two aliquots of 1.5 ml were prepared from each sample. On... more Twenty semen samples were collected and two aliquots of 1.5 ml were prepared from each sample. One sample of each pair (fraction-one) was used for evaluation of semen parameters and total acrosin activity of spermatozoa. The other sample of each pair (fraction-two) was mixed with an equal volume of Ham's F-10 medium and filtered through the Sperm PrepTMII. At the end of the filtration, the filtrate was pooled, sperm parameters were evaluated and total acrosin activity was assessed. Percentage of normal spermatozoa, sperm motility, and total acrosin activity of spermatozoa were significantly higher in the postfiltered fraction-two than in the fresh fraction-one. Considering the great importance of acrosin for fertilization, it is suggested that Sperm PrepTMII filtration method may be beneficial in preparing spermatozoa from infertile men with low acrosin profiles for assisted reproduction programs. Further studies will be necessary, however, in order to confirm this, since the present study concerned men with known fertility, human ; spermatozoa ; acrosin Acrosin, a serine proteinase associated with the acrosome of spermatozoa, appears to be involved in the acrosome reaction as well as the capability of spermatozoa to bind to and penetrate the zona pellucida (Rogers and Bentwood 1982; Zaneveld et al. 1990). Most of acrosin is present in the acrosome as a precursor, proacrosin. Proacrosin becomes activated during the fertilization process (Green 1978; Goodpasture et al. 1981). In vitro, proacrosin rapidly

Systems Biology in Reproductive Medicine, 1992

Semen samples collected from fertile donors (n-13) and pooled samples from idiopathic infertile m... more Semen samples collected from fertile donors (n-13) and pooled samples from idiopathic infertile men (n = 19) were used in this study. Measurements of the total sperm acrosin activity and the hypoosmotic swelling test (HOST) were performed in all the samples. The percentage of swollen spermatozoa and acrosin profiles were significantly lower in the infertile men than in the fertile donors. Considering the lowest values of the outcome of the HOST and the acrosin activity assay in the group of fertile men as the lowest normal values, it was proven that HOST and acrosin activity assay could identify subpopulations of infertile men of 37 and 26%, respectively. The results tend to support the employment of the HOST and the acrosin activity assay in the evaluation of idiopathic infertile men.

Journal of In Vitro Fertilization and Embryo Transfer, 1991

Journal of Assisted Reproduction and Genetics, 2012

Purpose To analyze the fertilization process related to polyspermy block in human oocytes using a... more Purpose To analyze the fertilization process related to polyspermy block in human oocytes using an in vitro culturing system for time-lapse cinematography. Methods We had 122 oocytes donated for this study from couples that provided informed consent. We recorded human oocytes at 2,000 to 2,800 frames every 10 s during the fertilization process and thereafter every 2 min using a new in vitro culture system originally developed by the authors for timelapse cinematography. We displayed 30 frames per second for analysis of the polyspermy block during fertilization. Results Three oocytes showed the leading and following sperm within the zona pellucida in the same microscopic field. The dynamic images obtained during the fertilization process using this new system revealed that once a leading sperm penetrated the zona pellucida and attached to the oocyte membrane, a following sperm was arrested from further penetration into the zona pellucida within 10 s. Conclusions The present results strongly suggest the existence of a novel mechanism of polyspermy block that takes place at the zona pellucida immediately after fertilization. These findings are clearly different from previous mechanisms describing polyspermy block as the oocyte membrane block to sperm penetration and the zona reaction. The finding presented herein thus represents a novel discovery about the highly complicated polyspermy block mechanism occurring in human oocytes. Keywords Polyspermy block. Time-lapse cinematography (TLC). Human fertilization process. Zona pellucida. Embryonic development Capsule We found that the novel mechanism of polyspermy block which is definitely different from the membrane block or zona reaction in human fertilization process using time-lapse cinematography. Preliminary results of this study have been presented at the 65th annual meeting of American Society of Reproductive Medicine (ASRM) in 2009 and 3rd Congress of the Asia Pacific Initiative on Reproduction (ASPIRE) in 2010.

Measurement of uptake and incorporation of nucleic acid precursors by preimplantation mouse embryos after development in vivo and in vitro

Journal of Assisted Reproduction and Genetics, 1992

To assay DNA and RNA synthesis by developing mouse embryos in vitro and in vivo, we measured the ... more To assay DNA and RNA synthesis by developing mouse embryos in vitro and in vivo, we measured the uptake and incorporation of 3H-thymidine and 3H-uridine by morulae and blastocysts. We also evaluated the effect of adding EDTA to the culture medium on the uptake and incorporation of nucleic acid precursors by blastocysts. Thymidine and uridine incorporation increased after morulae developed into early blastocysts both in vitro and in vivo. However, the rates of uptake and incorporation were significantly lower by embryos grown in vitro than by those grown in vivo. The ratios of incorporation to total uptake were similar in embryos grown in vitro and in vivo. EDTA (100 microM) added to the culture medium significantly increased the incorporation of uridine into RNA by blastocysts grown in vitro (P < 0.01) but did not increase the total uptake of uridine. These observations showed that both DNA and RNA synthesis increased during the early development of preimplantation embryos and that those activities were reduced in embryos undergoing development in vitro. The results also suggested that through the mechanism of EDTA effect in embryo culture remains unknown, it appeared to reduce the retardation of RNA synthesis by embryos cultured in vitro through a selective stimulation of uridine incorporation.

Human Reproduction Update, 2005

Induction of meiotic and post-meiotic alterations of male germ cells in vitro has been the target... more Induction of meiotic and post-meiotic alterations of male germ cells in vitro has been the target of several research efforts since 1960. However, to date, the establishment of an ideal culture system in which spermatogonial stem cells can be maintained and directed to proliferate and undergo meiosis and complete spermiogenesis does not exist. This is attributed to the difficulties concerning the isolation and purification of defined subpopulations of germ cells and the establishment of male germ cell lines. In addition, there is no adequate knowledge regarding the optimal biochemical conditions that promote the survival and differentiation of germ cells in long-term cultures. This review focuses on the methodologies that have been proved sufficient to achieve differentiation of cultured male germ cells. Furthermore, the factors regulating spermatogenesis and the technical prerequisites to achieve differentiation of cultured male germ cells are described. Finally, the role of in vitro cultures of immature diploid germ cells in the therapeutic management of men negative for haploid cells in their testes and the subsequent potential genetic and epigenetic risks are discussed.

Human Reproduction Update, 2003

Results from the transplantation of donor male germ cells into xenogeneic recipient seminiferous ... more Results from the transplantation of donor male germ cells into xenogeneic recipient seminiferous tubules indicate that donor spermatogonia are capable of differentiating to form spermatozoa morphologically characteristic of the donor species. Germ cell transplantation procedures combined with developments in freezing, culturing or enriching germ cell populations have applications of paramount importance in medicine, basic sciences and animal reproduction. Additionally, these techniques can serve as an alternative approach for gonadal protection and fertility preservation in patients with cancer. This article is a chronological critical review of the technological advances that followed the initial successful transplantation of mouse germ cells into recipient mice. Furthermore, the factors responsible for the immunological privilege properties of the testis and the parameters in¯uencing the potential of mammalian germ cells to undergo mitosis and meiosis within a xenogeneic testis are described. Finally, the role of human germ cell transplantation procedures in the therapeutic management of non-obstructive azoospermia is discussed.

Human Reproduction, 2002

BACKGROUND: Klinefelter's syndrome is the most frequent chromosomal abnormality in infertile men.... more BACKGROUND: Klinefelter's syndrome is the most frequent chromosomal abnormality in infertile men. In this study, the chromosomes of round spermatids and spermatogonia/primary spermatocytes from men with non-mosaic Klinefelter's syndrome were examined, together with the Sertoli cell secretory function and sperm morphometry. METHODS: Twenty-four men with non-mosaic Klinefelter's syndrome and nine men with obstructive azoospermia underwent therapeutic testicular biopsy. When spermatozoa in the final filtrate were present, they were processed for sperm morphometry or ICSI. Sperm morphometry was evaluated by the maximal length and width of the sperm head, the length of the midpiece and the ratio of the acrosomal region to the total surface area of the head. When round spermatids were present, they were processed for fluorescent in-situ hybridization (FISH). FISH was also applied to fragments of seminiferous tubules. Sertoli cell secretory function was measured by the amount of androgen binding protein (ABP) secreted in vitro. RESULTS: More than 93% of the evaluated round spermatids were normal. The proportions of 24,XY and of 24,XX round spermatids to the total number were significantly larger in men with Klinefelter's syndrome than in obstructed azoospermic men. Men with Klinefelter's syndrome who had spermatozoa in their testicular tissue (n ⍧ 12) were positive for both 46,XY and 47,XXY spermatogonia in their seminiferous tubules. In contrast, men with Klinefelter's syndrome without spermatozoa in their testicular tissue (n ⍧ 12) were positive for 47,XXY spermatogonia but negative for 46,XY spermatogonia in their seminiferous tubules. ABP profiles were significantly smaller in men with Klinefelter's syndrome who were negative for spermatozoa compared with men who were positive. Four pregnancies were achieved and five healthy babies were born. CONCLUSIONS: This study suggests that few 46,XXY spermatogonia undergo meiosis with an XX pairing and a Y univalent type of pairing. Hyperhaploid round spermatids (24,XY and 24,XX) may be produced by meiosis of 47,XXY spermatogonia. Men with Klinefelter's syndrome who are negative for testicular spermatozoa have a greater degree of Sertoli cell secretory dysfunction compared with men with Klinefelter's syndrome who are positive for spermatozoa. There are several defects in sperm morphometry with functional significance in men with Klinefelter's syndrome.

Human Reproduction, 1998

We applied the technique of ooplasmic elongating spermatid injection to the treatment of non-obst... more We applied the technique of ooplasmic elongating spermatid injection to the treatment of non-obstructive azoospermia. Mature oocytes were injected with elongating spermatids isolated from testicular biopsy material obtained from 13 non-obstructed azoospermic men. Seventy-three oocytes were successfully injected with elongating spermatids and were then cultured for 36 h. At 13 h post-injection 68 oocytes were found to be activated and 52 of them were fertilized. Forty-one 2-to 4-cell stage embryos developed from normally fertilized oocytes were transferred. At least two embryos were transferred to each female partner. Two pregnancies were achieved. Elongating spermatid injection may have a role in the treatment of non-obstructive azoospermia.

Human Reproduction, 2013

framework. First, it does not offer an adequate account of the reality in the clinic. Many fertil... more framework. First, it does not offer an adequate account of the reality in the clinic. Many fertility centers offer treatments to patients that are neither considered established medical treatment, nor regarded as experimental. Second, this view may bring about several negative effects for the patient. On the one hand, considering all procedures that are not yet established, as experimental treatment, would imply that these procedures can only be performed with the specific review of an Institutional Review Board. This could leave many patients waiting for a treatment they could benefit from, as most of them do not have the time to wait until the procedure is considered an established medical procedure. On the other hand, also the opposite may be the case: techniques being considered established too early, sometimes holding risks unknown to patients. A further drawback of the dichotomy is that if a technique is no longer considered experimental, centers offering the technique may no longer consider it useful to gather and critically examine (follow up) data. On EXCO's request, the special interests groups (SIG's) on Safety & Quality in ART and on Ethics & Law have considered this issue and drawn up a document on the notion of 'experimental'. We propose a conceptual framework that distinguishes between three instead of two types of treatment and describe a continuum from experimental over innovative to established treatment. With the introduction of the category 'innovative treatment', we want to provide an answer to the problematic dichotomy between the two extreme points of the continuum: experimental treatment and established treatment. In our proposal, a procedure is to be viewed experimental, innovative, or established based on four criteria: efficacy (proof of principle), safety, efficiency, and procedural transparency/certainty. We also provide a tool to facilitate the discussion and reach an agreement about the classification of treatments in the field of infertility. Finally, we formulate recommendations regarding the role and responsibilities of centers offering specific treatments with regard to: the informed consent of the patient; the collection of data that allow continued and long-term evaluation; the publication of these data, regardless of treatment success; the need for specific or general approval of local ethics committees, etc.

Fertility and Sterility, 2004

Fertility and Sterility, 2003

Materials and Methods: Twenty frozen semen samples were obtained from 16 subjects (cancer patient... more Materials and Methods: Twenty frozen semen samples were obtained from 16 subjects (cancer patients, nϭ6 and male infertility patients enrolled in an ART program, nϭ10) who required disposal of their samples stored in our sperm bank. Each sample was evaluated for motile sperm count, percent and progressive motility, viability and morphology (strict criteria). Wilcoxon signed-rank test was used to test for statistical differences in sperm parameters. Results: There was a significant decrease in all sperm parameters after the thaw-refreeze process. Motile sperm count, percent sperm motility, progressive sperm motility, viability and morphology decreased from 5.8 million/mL to 1.9 million/mL (PϽ0.01), 38.3% to 20.2% (PϽ0.01), 28.4% to 11.5% (PϽ0.01), 38.7% to 19.3% (PϽ0.01), and from 5.3% to 4.3%, respectively. There was no difference between cancer and ART patients regarding the outcome of the refreeze-thaw process. Conclusion: Normal and viable motile sperm can be obtained after thaw-refreeze sperm using the standard vapor freezing method. The number of good quality spermatozoa are adequate for in vitro fertilization using intracytoplasmic sperm injection. Therefore, leftover frozen-thawed specimens can be refrozen for future use. This approach has benefits specially for cancer patients who urge to start the chemotherapy/radiotherapy and cannot freeze multiple specimens. P-323 The effect of varicocelectomy on men with painful varicoceles. Alexander Epelbaum, William Blank. SUNY Downstate, Brooklyn, NY. P-328 Microdissection testis sperm extraction does not increase sperm retrieval rates but does yield improved sperm concentration.

Fertility and Sterility, 2005

(IVF) cycle is effective at reducing the multiple pregnancy rate (MPR) and the ovarian hyperstimu... more (IVF) cycle is effective at reducing the multiple pregnancy rate (MPR) and the ovarian hyperstimulation syndrome (OHSS) rate, without compromising the pregnancy rate per embryo transfer (PR/ET). DESIGN: Retrospective chart review from January 1, 2003 to December 31, 2004. MATERIALS AND METHODS: In IVF there is a group of high prognosis patients characterized by age Յ 36, two embryos transferred on D3, and having Ն one embryo cryopreserved. Within this group is a particular subset that was physician-elected to be candidates for ESET (Group I). The parameters assessed to recommend ESET included response to hMG, number of supernumerary embryos cryopreserved, risk of OHSS, and preexisting medical conditions. Group II are the remainder high prognosis patients. Exclusions were poor responders, ICSI rescue and poor embryo quality (requiring day 2 assisted hatching) patients. A retrospective chart review was undertaken to calculate the mean age, number of oocytes retrieved and number of supernumerary embryos cryopreserved. The PR/ET, implantation rate per embryo transferred (IR), MPR, and the incidence of OHSS that required hospitalization was calculated. Chi square and t-test statistical analysis were applied where appropriate. RESULTS: CONCLUSION: One embryo transferred versus two embryos on D3 significantly reduced the PR/ET and the MPR. However, the IR was not significantly different suggesting that elective transfer of a single embryo can result in an acceptable pregnancy rate, with a significant reduction in the MPR, in the particularly high responder patient. Even though the numbers are small, elective transfer of a single embryo does not appear to reduce the incidence of OHSS. Further study is indicated.