ovum cleavage stage


Summary: The earliest developmental stage of a fertilized ovum (ZYGOTE) during which there are several mitotic divisions within the ZONA PELLUCIDA. Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally covers the period up to 16-cell MORULA.

Top Publications

  1. Yang W, Hwu Y, Lee R, Li S, Lin S, Fleming S. Early cleavage does not predict treatment outcome following the use of GnRH antagonists in women older than 35. Fertil Steril. 2007;88:1573-8 pubmed
    ..To compare the early-cleavage rates and the implantation potential of embryos between the GnRH antagonist and agonist long stimulation protocols in women older than 35 years...
  2. Alvarez C, Taronger R, García Garrido C, González de Merlo G. Zygote score and status 1 or 2 days after cleavage and assisted reproduction outcome. Int J Gynaecol Obstet. 2008;101:16-20 pubmed publisher
    ..To determine whether pronuclear morphology is a useful additional criterion when selecting embryos for transfer...
  3. van Montfoort A, Dumoulin J, Kester A, Evers J. Early cleavage is a valuable addition to existing embryo selection parameters: a study using single embryo transfers. Hum Reprod. 2004;19:2103-8 pubmed
    ..This study investigated the predictive value of early cleavage (EC) as an additional parameter for selecting the embryo with the highest implantation potential by using data from SET's...
  4. Herrid M, Nguyen V, Hinch G, McFarlane J. Leptin has concentration and stage-dependent effects on embryonic development in vitro. Reproduction. 2006;132:247-56 pubmed
  5. Jeong H, Kim H, Lee S, Kwack K, Ahn S, Choi Y, et al. Gene expression profiling of the pre-implantation mouse embryo by microarray analysis: comparison of the two-cell stage and two-cell block. Theriogenology. 2006;66:785-96 pubmed
  6. Holte J, Berglund L, Milton K, Garello C, Gennarelli G, Revelli A, et al. Construction of an evidence-based integrated morphology cleavage embryo score for implantation potential of embryos scored and transferred on day 2 after oocyte retrieval. Hum Reprod. 2007;22:548-57 pubmed
    ..Evidence-based morphological embryo scoring models for ranking of implantation potential are still scarce, and the need for a precise model increases when aiming for singleton pregnancies...
  7. Ohsugi M, Zheng P, Baibakov B, Li L, Dean J. Maternally derived FILIA-MATER complex localizes asymmetrically in cleavage-stage mouse embryos. Development. 2008;135:259-69 pubmed
    ..If so, the plasticity of the FILIA-MATER complex localization may reflect the regulative nature of preimplantation mouse development...
  8. Edwards R. Genetics of polarity in mammalian embryos. Reprod Biomed Online. 2005;11:104-14 pubmed
    ..Some implications of these findings are considered...
  9. Vajta G, Nagy Z. Are programmable freezers still needed in the embryo laboratory? Review on vitrification. Reprod Biomed Online. 2006;12:779-96 pubmed
    ..The opinion of the authors is that vitrification is the future of cryopreservation. The public have the final say in whether they want and allow this future to arrive...

More Information


  1. Windt M, Kruger T, Coetzee K, Lombard C. Comparative analysis of pregnancy rates after the transfer of early dividing embryos versus slower dividing embryos. Hum Reprod. 2004;19:1155-62 pubmed
    ..We compared retrospectively the pregnancy outcome in two subgroups of ICSI patients, using early division (26 h post injection) to the 2-cell stage as a criterion for embryo quality and viability (ability to produce a pregnancy)...
  2. Chen C, Kattera S. Comparison of pronuclear zygote morphology and early cleavage status of zygotes as additional criteria in the selection of day 3 embryos: a randomized study. Fertil Steril. 2006;85:347-52 pubmed
    ..However, in routine practice, it is impractical to use both these criteria to select embryos on day 3. The objective of the present study was to find which of the two criteria is more predictive in terms of implantation and pregnancy...
  3. Fisch J, Rodriguez H, Ross R, Overby G, Sher G. The Graduated Embryo Score (GES) predicts blastocyst formation and pregnancy rate from cleavage-stage embryos. Hum Reprod. 2001;16:1970-5 pubmed
    ..Algorithms for predicting IVF outcomes based on the presence of early developmental milestones have been proposed. Here we introduce the Graduated Embryo Score (GES)...
  4. Salumets A, Hyden Granskog C, Suikkari A, Tiitinen A, Tuuri T. The predictive value of pronuclear morphology of zygotes in the assessment of human embryo quality. Hum Reprod. 2001;16:2177-81 pubmed
    ..In the present study PN stage morphology was assessed and combined with a single embryo transfer in order to investigate whether currently used zygote classifications are able to predict embryo quality and implantation rates...
  5. Nagy Z, Dozortsev D, Diamond M, Rienzi L, Ubaldi F, Abdelmassih R, et al. Pronuclear morphology evaluation with subsequent evaluation of embryo morphology significantly increases implantation rates. Fertil Steril. 2003;80:67-74 pubmed
    ..To elucidate the relative predictive value of implantation markers at different stages of preimplantation development...
  6. Ma J, Svoboda P, Schultz R, Stein P. Regulation of zygotic gene activation in the preimplantation mouse embryo: global activation and repression of gene expression. Biol Reprod. 2001;64:1713-21 pubmed
  7. Li X, Morris L, Allen W. Influence of co-culture during maturation on the developmental potential of equine oocytes fertilized by intracytoplasmic sperm injection (ICSI). Reproduction. 2001;121:925-32 pubmed
    ..These results demonstrate a beneficial influence of co-culture with either oviduct epithelial cells or fetal fibroblasts for maturation of oocytes in vitro...
  8. Ciray H, Ulug U, Bahceci M. Transfer of early-cleaved embryos increases implantation rate in patients undergoing ovarian stimulation and ICSI-embryo transfer. Reprod Biomed Online. 2004;8:219-23 pubmed
    ..These results indicate that, when inspected, early cleavage increases the implantation rate in ICSI patients...
  9. Łukaszuk K, Liss J, Białobrzeska D, Wójcikowski C. [Prognostic value of the pronuclear morphology pattern of zygotes for implantation rate]. Ginekol Pol. 2003;74:508-13 pubmed
    ..Pronuclear stage scoring system has been used in IVF recently as an additional parameter...
  10. Kawamura K, Sato N, Fukuda J, Kodama H, Kumagai J, Tanikawa H, et al. The role of leptin during the development of mouse preimplantation embryos. Mol Cell Endocrinol. 2003;202:185-9 pubmed
    ..These findings raise the possibility that leptin regulates the development of mouse preimplantation embryo through a paracrine pathway...
  11. Scott L. Pronuclear scoring as a predictor of embryo development. Reprod Biomed Online. 2003;6:201-14 pubmed
    ..The use of PN scoring can help predict embryos that have poor developmental potential, aid in early selection and may indicate the health of the oocyte...
  12. Salumets A, Hyden Granskog C, Mäkinen S, Suikkari A, Tiitinen A, Tuuri T. Early cleavage predicts the viability of human embryos in elective single embryo transfer procedures. Hum Reprod. 2003;18:821-5 pubmed
    ..The current study was undertaken to assess whether early cleavage could be used as a marker of embryo competence in eSET procedures...
  13. Rienzi L, Ubaldi F, Iacobelli M, Ferrero S, Minasi M, Martinez F, et al. Day 3 embryo transfer with combined evaluation at the pronuclear and cleavage stages compares favourably with day 5 blastocyst transfer. Hum Reprod. 2002;17:1852-5 pubmed
    ..The respective advantages of day 3 and day 5 embryo transfer are a matter of debate. Previous comparisons did not include pronuclear stage zygote scoring and cumulative success rates (fresh and cryopreserved embryos)...
  14. Lundin K, Bergh C, Hardarson T. Early embryo cleavage is a strong indicator of embryo quality in human IVF. Hum Reprod. 2001;16:2652-7 pubmed
    ..It has been shown that human embryos which cleave early, i.e. complete the first mitotic division within 25-27 h post insemination, provide higher pregnancy and implantation rates...
  15. Bos Mikich A, Mattos A, Ferrari A. Early cleavage of human embryos: an effective method for predicting successful IVF/ICSI outcome. Hum Reprod. 2001;16:2658-61 pubmed
    ..We investigated whether extending the time for selection of cleaved embryos to 29 h post-insemination/ICSI had a similar effect on pregnancy and implantation rates...
  16. Petersen C, Mauri A, Ferreira R, Baruffi R, Franco Junior J. Embryo selection by the first cleavage parameter between 25 and 27 hours after ICSI. J Assist Reprod Genet. 2001;18:209-12 pubmed
    ..The objective of this study was to assess first embryo cleavage (FEC) 25-27 h after intracytoplasmic sperm injection (ICSI) as a parameter for the embryo selection process...
  17. Borowczyk E, Caton J, Redmer D, Bilski J, Weigl R, Vonnahme K, et al. Effects of plane of nutrition on in vitro fertilization and early embryonic development in sheep. J Anim Sci. 2006;84:1593-9 pubmed
    ..These data indicate that undernutrition of donor ewes, resulting in lower BW and BCS, has a negative effect on oocyte quality, which results in lower rates of cleavage and blastocyst formation. ..
  18. Zernicka Goetz M. First cell fate decisions and spatial patterning in the early mouse embryo. Semin Cell Dev Biol. 2004;15:563-72 pubmed
    ..This could influence development of patterning after implantation. These early polarity cues serve to bias patterning and not as definitive determinants. ..
  19. Somfai T, Ozawa M, Noguchi J, Kaneko H, Ohnuma K, Karja N, et al. Diploid porcine parthenotes produced by inhibition of first polar body extrusion during in vitro maturation of follicular oocytes. Reproduction. 2006;132:559-70 pubmed
    ..0%) was similar to that in diploid parthenotes. These results suggest that the proportion of homozygous and heterozygous genes does not affect in vitro embryo development to the blastocyst stage. ..
  20. Song H, Cauffman K, Chan A, Zhou Y, King M, Etkin L, et al. Hermes RNA-binding protein targets RNAs-encoding proteins involved in meiotic maturation, early cleavage, and germline development. Differentiation. 2007;75:519-28 pubmed
    ..We propose that as an RNA-binding protein, Hermes may be involved in maturation, cleavage events at the vegetal pole and germ cell development by negatively regulating the expression of RINGO/Spy, Mos, and Xcat2 mRNAs. ..
  21. Wang Q, Zhuang G, Zhou C, Li J, Zhong Y, Xu Y, et al. [Expression of soluble human leukocyte antigen G and its relationship to embryo development]. Zhonghua Fu Chan Ke Za Zhi. 2005;40:112-5 pubmed
    ..05), but it had relationship with the cell number (r = 0.267). Cleavage embryos express sHLA-G which is related with the embryo development. ..
  22. Neuber E, Mahutte N, Arici A, Sakkas D. Sequential embryo assessment outperforms investigator-driven morphological assessment at selecting a good quality blastocyst. Fertil Steril. 2006;85:794-6 pubmed
    ..The sequential embryo assessment algorithm was significantly better at selecting the best embryo and selecting a blastocyst compared with the morphology-only method. ..
  23. Suzuki C, Yoshioka K, Sakatani M, Takahashi M. Glutamine and hypotaurine improves intracellular oxidative status and in vitro development of porcine preimplantation embryos. Zygote. 2007;15:317-24 pubmed
    ..These results indicate that the presence of Gln and HT in PZM-5 from day 2 to day 3 promotes the development of porcine embryos by improvement of intracellular oxidative status. ..
  24. Yavin S, Aroyo A, Roth Z, Arav A. Embryo cryopreservation in the presence of low concentration of vitrification solution with sealed pulled straws in liquid nitrogen slush. Hum Reprod. 2009;24:797-804 pubmed publisher
    ..5% VS. This method enables maintenance of high cooling rates as well as reduction of cryoprotectant concentration, despite the use of a sealed container that helps to reduce the potential risk of contamination. ..
  25. Bergh C, Loft A, Lundin K, Ziebe S, Nilsson L, Wikland M, et al. Chromosomal abnormality rate in human pre-embryos derived from in vitro fertilization cycles cultured in the presence of Follicular-Fluid Meiosis Activating Sterol (FF-MAS). Hum Reprod. 2004;19:2109-17 pubmed
    ..FF-MAS increased the rate of aneuploidy and had detrimental effects on cleavage and pre-embryo development, when exposed both before and after fertilization. ..
  26. Kameyama Y, Ohnishi H, Shimoi G, Hashizume R, Ito M, Smith L. Asymmetrical allocation of mitochondrial DNA to blastomeres during the first two cleavages in mouse embryos. Reprod Fertil Dev. 2010;22:1247-53 pubmed publisher
  27. Ottosen L, Hindkjaer J, Lindenberg S, Ingerslev H. Murine pre-embryo oxygen consumption and developmental competence. J Assist Reprod Genet. 2007;24:359-65 pubmed
    ..Preliminary data from the present study suggest that oxygen consumption in cleavage stage embryos may be an indicator, but a not a strong predictor, of subsequent development to expanded blastocysts. ..
  28. Rooke J, Ainslie A, Watt R, Alink F, McEvoy T, Sinclair K, et al. Dietary carbohydrates and amino acids influence oocyte quality in dairy heifers. Reprod Fertil Dev. 2009;21:419-27 pubmed
    ..These findings have implications for both diet formulation and feeding regimes. ..
  29. Lyons D, Weisblat D. D quadrant specification in the leech Helobdella: actomyosin contractility controls the unequal cleavage of the CD blastomere. Dev Biol. 2009;334:46-58 pubmed publisher
  30. Gonzalez R, Ruiz León Y, Gomendio M, Roldan E. The effect of glucocorticoids on mouse oocyte in vitro maturation and subsequent fertilization and embryo development. Toxicol In Vitro. 2010;24:108-15 pubmed publisher
  31. Check J, Bollendorf A, Dix E, Katsoff D. Effect of fertilization by intracytoplasmic sperm injection versus conventional insemination on embryo cleavage rates. Clin Exp Obstet Gynecol. 2010;37:183-4 pubmed
  32. Khatir H, Anouassi A. The first dromedary (Camelus dromedarius) offspring obtained from in vitro matured, in vitro fertilized and in vitro cultured abattoir-derived oocytes. Theriogenology. 2006;65:1727-36 pubmed
    ..In conclusion, this is the first reported offspring in camelids obtained by transfer of embryos produced by IVM, IVF and IVC using abattoir-derived oocytes, fresh semen and culture in a semi-defined medium. ..
  33. Vural B, Sofuoglu K, Caliskan E, Delikara N, Aksoy E, Uslu H, et al. Predictors of intracytoplasmic sperm injection (ICSI) outcome in couples with and without male factor infertility. Clin Exp Obstet Gynecol. 2005;32:158-62 pubmed
    ..4 +/- 24.6, p = 0.02). Leucocytospermia, hCG-day E2 level and endometrial thickness, normal sperm morphology, and number of good quality embryos are predictors of implantation, clinical pregnancy and live birth rate following ICSI. ..
  34. Li G, Bunch T, White K, Rickords L, Liu Y, Sessions B. Denuding and centrifugation of maturing bovine oocytes alters oocyte spindle integrity and the ability of cytoplasm to support parthenogenetic and nuclear transfer embryo development. Mol Reprod Dev. 2006;73:446-51 pubmed
    ..Embryo development of denuded and centrifuged oocytes may differ depending on the time of removal of cumulus cells. ..
  35. Probst A, Okamoto I, Casanova M, el Marjou F, Le Baccon P, Almouzni G. A strand-specific burst in transcription of pericentric satellites is required for chromocenter formation and early mouse development. Dev Cell. 2010;19:625-38 pubmed publisher
    ..We conclude that the exquisite strand-specific expression dynamics at major satellites during the 2-cell stage, with both up and downregulation, are necessary events for proper chromocenter organization and developmental progression. ..
  36. Tusell L, Latre L, Ponsa I, Miro R, Egozcue J, Genesca A. Capping of radiation-induced DNA breaks in mouse early embryos. J Radiat Res. 2004;45:415-22 pubmed
    ..The presence of additional telomere signals at the broken chromosome ends in mouse germ cells and early embryos, compatible with de novo formation of telomeres, was not frequent. ..
  37. Vandaele L, Mateusen B, Maes D, de Kruif A, Van Soom A. Is apoptosis in bovine in vitro produced embryos related to early developmental kinetics and in vivo bull fertility?. Theriogenology. 2006;65:1691-703 pubmed
    ..In vivo bull fertility could hardly be correlated with in vitro blastocyst yield and could not be correlated with appearance of apoptosis. ..
  38. Rogers N, Halet G, Piao Y, Carroll J, Ko M, Swann K. The absence of a Ca(2+) signal during mouse egg activation can affect parthenogenetic preimplantation development, gene expression patterns, and blastocyst quality. Reproduction. 2006;132:45-57 pubmed
    ..These data suggest that activation of mouse eggs in the absence of a Ca(2+) signal does not affect initial parthenogenetic events, but can influence later gene expression and development. ..
  39. Anas M, Lee M, Zhou C, Hammer M, Slow S, Karmouch J, et al. SIT1 is a betaine/proline transporter that is activated in mouse eggs after fertilization and functions until the 2-cell stage. Development. 2008;135:4123-30 pubmed publisher
    ..Thus, SIT1 is likely to be a developmentally restricted betaine transporter in mouse preimplantation embryos that is activated by fertilization. ..
  40. Mel nikova E, Uteshev V, Pashovkin T, Sokolova A, Iashin V, Karnaukhov V, et al. [Changes in the permeability of amphibian embryo envelope for fluorochromes under the action of ultrasound]. Biofizika. 2005;50:500-4 pubmed
    ..64 MHz and the same intensity increased that for fluorescein with the retention of low permeability for FDA. Embryos continued the normal development after treatment with ultrasound under these conditions. ..
  41. Revel A, Moshe N, Helman A, Safran A, Simon A, Koler M. Mouse embryos generated from frozen-thawed oocytes can successfully survive a second cryopreservation. Hum Reprod. 2004;19:666-9 pubmed
    ..Nevertheless, embryos generated from cryopreserved oocytes can survive cryopreservation and develop to the blastocyst stage at rates comparable with embryos obtained from fresh oocytes. ..
  42. Webb S, Miller A. Ca2+ signalling and early embryonic patterning during zebrafish development. Clin Exp Pharmacol Physiol. 2007;34:897-904 pubmed
    ..4. The potential downstream targets of these Ca2+ transients are also discussed, as well as how they may integrate with other pattern-forming signalling pathways known to modulate early developmental events. ..
  43. Dumont M. [Embryo quality and selection]. J Gynecol Obstet Biol Reprod (Paris). 2008;37 Suppl 1:S9-13 pubmed publisher
    ..Imaging software (Fertimorph) now facilitates the evaluation of embryo quality. ..
  44. Rehman K, Bukulmez O, Langley M, Carr B, Nackley A, Doody K, et al. Late stages of embryo progression are a much better predictor of clinical pregnancy than early cleavage in intracytoplasmic sperm injection and in vitro fertilization cycles with blastocyst-stage transfer. Fertil Steril. 2007;87:1041-52 pubmed
    ..The embryo progression index and BQS may also be used for this purpose. ..
  45. Hourvitz A, Maman E, Brengauz M, Machtinger R, Dor J. In vitro maturation for patients with repeated in vitro fertilization failure due to "oocyte maturation abnormalities". Fertil Steril. 2010;94:496-501 pubmed publisher
    ..Two patients with previous genuine EFS conceived and delivered. IVM should be considered for women with previous genuine EFS. The role of IVM in other indications of oocyte maturation deficits warrants further investigation. ..
  46. Leoni G, Succu S, Satta V, Paolo M, Bogliolo L, Bebbere D, et al. In vitro production and cryotolerance of prepubertal and adult goat blastocysts obtained from oocytes collected by laparoscopic oocyte-pick-up (LOPU) after FSH treatment. Reprod Fertil Dev. 2009;21:901-8 pubmed publisher
    ..However, we can assume that the quality of re-expanded embryos does not differ between the two groups. ..
  47. Torres Padilla M, Zernicka Goetz M. Role of TIF1alpha as a modulator of embryonic transcription in the mouse zygote. J Cell Biol. 2006;174:329-38 pubmed
    ..These studies indicate that TIF1alpha is a factor that modulates the expression of a set of genes during the first wave of genome activation in the mouse embryo. ..
  48. Piliszek A, Modlinski J, Pysniak K, Karasiewicz J. Foetal fibroblasts introduced to cleaving mouse embryos contribute to full-term development. Reproduction. 2007;133:207-18 pubmed
    ..Transdifferentiation as opposed to reprogramming by cell fusion can be considered as underlying cellular processes in these chimeras. ..
  49. Wongsrikeao P, Kaneshige Y, Ooki R, Taniguchi M, Agung B, Nii M, et al. Effect of the removal of cumulus cells on the nuclear maturation, fertilization and development of porcine oocytes. Reprod Domest Anim. 2005;40:166-70 pubmed
    ..Particularly, the attachment of cumulus cells to the oocyte during IVF promotes embryonic development. ..
  50. Ninhaus Silveira A, Foresti F, de Azevedo A. Structural and ultrastructural analysis of embryonic development of Prochilodus lineatus (Valenciennes, 1836) (Characiforme; Prochilodontidae). Zygote. 2006;14:217-29 pubmed
    ..At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption. ..
  51. Vlaisavljevic V, Cizek Sajko M, Kovac V. Multinucleation and cleavage of embryos derived from in vitro-matured oocytes. Fertil Steril. 2006;86:487-9 pubmed
    ..1%). The embryos derived from in vitro-matured oocytes after the hCG priming protocol also showed a lower incidence of multinucleated blastomeres. Pregnancies were recorded only in the hCG primed patients. ..
  52. Männer J, Thrane L, Norozi K, Yelbuz T. In vivo imaging of the cyclic changes in cross-sectional shape of the ventricular segment of pulsating embryonic chick hearts at stages 14 to 17: a contribution to the understanding of the ontogenesis of cardiac pumping function. Dev Dyn. 2009;238:3273-84 pubmed publisher
    ..The functional significance of our data is discussed with respect to early cardiac pumping function...
  53. Fujimori T. Preimplantation development of mouse: a view from cellular behavior. Dev Growth Differ. 2010;52:253-62 pubmed publisher
    ..Here, mouse preimplantation embryonic development is briefly summarized and our current understanding of this complex process based on recent observations is reviewed...
  54. Schulze J, Schierenberg E. Cellular pattern formation, establishment of polarity and segregation of colored cytoplasm in embryos of the nematode Romanomermis culicivorax. Dev Biol. 2008;315:426-36 pubmed publisher
    ..A scenario is sketched suggesting why and how during evolution the observed differences between R. culicivorax and C. elegans may have evolved...
  55. Theusch E, Brown K, Pelegri F. Separate pathways of RNA recruitment lead to the compartmentalization of the zebrafish germ plasm. Dev Biol. 2006;292:129-41 pubmed
    ..Our observations suggest that separate pathways of RNA recruitment facilitate the compartmentalization of the zebrafish germ plasm...
  56. Brezinova J, Oborna I, Svobodova M, Fingerova H. Evaluation of day one embryo quality and IVF outcome--a comparison of two scoring systems. Reprod Biol Endocrinol. 2009;7:9 pubmed publisher
  57. Racowsky C, Vernon M, Mayer J, Ball G, Behr B, Pomeroy K, et al. Standardization of grading embryo morphology. Fertil Steril. 2010;94:1152-3 pubmed publisher
  58. Felipe A, Teruel M, Cabodevila J, Callejas S. Morphological aspects of in vivo cleavage in Myocastor coypus (coypu). Anat Histol Embryol. 2004;33:75-80 pubmed
    ..The percentage of peri-vitelline space occupied by the embryonic mass ranged from 74.1 to 95.8% for all the substages. The cleavage pattern, developed in the oviduct, was of a rotational holoblastic type and asynchronic...
  59. Loutradi K, Kolibianakis E, Venetis C, Papanikolaou E, Pados G, Bontis I, et al. Cryopreservation of human embryos by vitrification or slow freezing: a systematic review and meta-analysis. Fertil Steril. 2008;90:186-93 pubmed
    ..the literature systematically in order to identify prospective comparative trials answering the following question: Is vitrification of human embryos associated with a higher postthawing survival rate as compared with slow freezing?..
  60. Calongos G, Hasegawa A, Komori S, Koyama K. Comparison of urinary and recombinant follicle-stimulating hormone in in vitro growth, maturation, and fertilization of mouse preantral follicles. Fertil Steril. 2008;89:1482-9 pubmed
    ..To compare the effects of urinary and recombinant follicle-stimulating hormone (FSH) on follicular development, oocyte maturation, and fertilization...
  61. Kawahara A, Che Y, Hanaoka R, Takeda H, Dawid I. Zebrafish GADD45beta genes are involved in somite segmentation. Proc Natl Acad Sci U S A. 2005;102:361-6 pubmed
    ..These results indicate that regulated expression of gadd45beta genes in the anterior PSM is required for somite segmentation...
  62. Liao H, Lin G, Lu C, Gong F, Xiao H, Lu G. [Research on the selection of embryos for transfer using a combined grading for embryo growth rate and morphology and zygote pronuclear morphology]. Zhonghua Fu Chan Ke Za Zhi. 2006;41:319-21 pubmed
    ..To evaluate the value of using a combined grading for embryo growth rate and morphology and zygote pronuclear morphology, and to select embryos for transfer in clinical in-vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI)...
  63. Vinot S, Le T, Ohno S, Pawson T, Maro B, Louvet Vallee S. Asymmetric distribution of PAR proteins in the mouse embryo begins at the 8-cell stage during compaction. Dev Biol. 2005;282:307-19 pubmed
    ..Finally, they reinforce the idea that the first developmentally relevant asymmetries are set up during compaction...
  64. Hiiragi T, Alarcon V, Fujimori T, Louvet Vallee S, Maleszewski M, Marikawa Y, et al. Where do we stand now? Mouse early embryo patterning meeting in Freiburg, Germany (2005). Int J Dev Biol. 2006;50:581-6; discussion 586-7 pubmed
    ..However, if the "prepatterning model" is correct, the latter will require critical reassessment...
  65. Wu Y, Tang L, Cai J, Lu X, Xu J, Zhu X, et al. High bone morphogenetic protein-15 level in follicular fluid is associated with high quality oocyte and subsequent embryonic development. Hum Reprod. 2007;22:1526-31 pubmed
    ..The aim of this study is to investigate BMP-15 level in human follicular fluid (FF) and its possible role in determining oocyte quality and developmental potential...
  66. Méo S, Yamazaki W, Ferreira C, Perecin F, Saraiva N, Leal C, et al. Parthenogenetic activation of bovine oocytes using single and combined strontium, ionomycin and 6-dimethylaminopurine treatments. Zygote. 2007;15:295-306 pubmed
  67. Lu C, Mains P. Mutations of a redundant alpha-tubulin gene affect Caenorhabditis elegans early embryonic cleavage via MEI-1/katanin-dependent and -independent pathways. Genetics. 2005;170:115-26 pubmed
    ..Genetic studies suggest that this tba-2 mutation has a "poisonous" effect on microtubule function...
  68. Ye J, Coleman J, Hunter M, Craigon J, Campbell K, Luck M. Physiological temperature variants and culture media modify meiotic progression and developmental potential of pig oocytes in vitro. Reproduction. 2007;133:877-86 pubmed
    ..Inclusion of 20% follicular fluid in the oocyte medium restored the blastocyst rate to that seen at higher temperatures. Thus, FSH and follicular fluid may allow oocytes to achieve normal developmental potential at in vivo temperatures...
  69. Yang C, Kou Z, Wang K, Jiang Y, Mao W, Sun Q, et al. Quantitative analysis of mitochondrial DNAs in macaque embryos reprogrammed by rabbit oocytes. Reproduction. 2004;127:201-5 pubmed
    ..The ratio of nuclear donor mtDNA to oocyte mtDNA dropped sharply from 2% at the 1-cell stage to 0.011% at the blastocyst stage. These results suggest that maternal mtDNA replicates after the morula stage...
  70. Stern J, Goldman M, Hatasaka H, MacKenzie T, Surrey E, Racowsky C. Optimizing the number of cleavage stage embryos to transfer on day 3 in women 38 years of age and older: a Society for Assisted Reproductive Technology database study. Fertil Steril. 2009;91:767-76 pubmed publisher
    ..To determine the optimal number of day 3 embryos to transfer in women >or=38 years by conducting an evidence-based evaluation...
  71. Edwards R, Hansis C. Initial differentiation of blastomeres in 4-cell human embryos and its significance for early embryogenesis and implantation. Reprod Biomed Online. 2005;11:206-18 pubmed
    ..Special attention is paid to well-characterized trophectoderm, the trophectoderm stem cell, and possible new forms of clinical application...
  72. Fancsovits P, Tóthné Z, Murber A, Takács F, Papp Z, Urbancsek J. Correlation between first polar body morphology and further embryo development. Acta Biol Hung. 2006;57:331-8 pubmed
    ..However, we observed a lower viability of oocytes with a large PB. Since there are contradictions in this and previous observations, an extensive study is needed with standard hormonal stimulation protocol and oocyte evaluation criteria...
  73. Paternot G, Devroe J, Debrock S, D Hooghe T, Spiessens C. Intra- and inter-observer analysis in the morphological assessment of early-stage embryos. Reprod Biol Endocrinol. 2009;7:105 pubmed publisher
    ..The aim of this study was to determine the intra- and inter-observer variability in the evaluation of embryo quality. Multilevel images of embryos on day 1, day 2 and day 3, were analysed using different morphological parameters...
  74. Sonehara H, Nagata M, Aoki F. Roles of the first and second round of DNA replication in the regulation of zygotic gene activation in mice. J Reprod Dev. 2008;54:381-4 pubmed
    ..These results suggest that the transcriptionally repressive state seems to be established after the second round of DNA replication...
  75. Luna M, Duke M, Copperman A, Grunfeld L, Sandler B, Barritt J. Blastocyst embryo transfer is associated with a sex-ratio imbalance in favor of male offspring. Fertil Steril. 2007;87:519-23 pubmed
    ..To evaluate the sex ratio of offspring born after blastocyst transfers...
  76. Naether O, Rudolf K, Fischer R, Baukloh V, Schmidt C, Held K. Pregnancy after vitrification of pronuclear stage oocytes biopsied for polar body aneuploidy screening. Reprod Biomed Online. 2008;16:268-70 pubmed
    ..After 2 weeks, a positive pregnancy test indicated successful implantation. The gestation is developing normally and is presently (end of September 2007) in the 22nd week...
  77. Amarin Z. A flexible protocol for cryopreservation of pronuclear and cleavage stage embryos created by conventional in vitro fertilization and intracytoplasmic sperm injection. Eur J Obstet Gynecol Reprod Biol. 2004;117:189-93 pubmed
    ..To evaluate the hospital's cryopreservation protocol...
  78. Luo Q, Yang J, Zeng Q, Zhu X, Qian Y, Huang H. 50-Hertz electromagnetic fields induce gammaH2AX foci formation in mouse preimplantation embryos in vitro. Biol Reprod. 2006;75:673-80 pubmed
    ..The DNA damage induced by EMFs could be at least partly repaired by the natural activation of DNA damage-repair mechanism or prevented by the simultaneous treatment of noise magnetic fields...
  79. Papanikolaou E, Camus M, Kolibianakis E, Van Landuyt L, Van Steirteghem A, Devroey P. In vitro fertilization with single blastocyst-stage versus single cleavage-stage embryos. N Engl J Med. 2006;354:1139-46 pubmed
  80. Rodriguez K, Farin C. Developmental capacity of bovine cumulus oocyte complexes after transcriptional inhibition of germinal vesicle breakdown. Theriogenology. 2004;61:1499-511 pubmed
    ..001 ). Following release from arrest, maturation and fertilization, the proportion of COC that cleaved by 72 hpi was decreased by treatment with DRB (DRB: 78+/-3% versus..
  81. Saikhun J, Kitiyanant N, Songtaveesin C, Pavasuthipaisit K, Kitiyanant Y. Development of swamp buffalo (Bubalus bubalis) embryos after parthenogenetic activation and nuclear transfer using serum fed or starved fetal fibroblasts. Reprod Nutr Dev. 2004;44:65-78 pubmed
    ..The results of this work can be used to establish effective activation protocols for buffalo oocytes which can be used during nuclear transfer experiments...
  82. Aktan T, Montag M, Duman S, Gorkemli H, Rink K, Yurdakul T. Use of a laser to detect viable but immotile spermatozoa. Andrologia. 2004;36:366-9 pubmed
    ..It is concluded that laser sperm interaction allows for the identification of viable but immotile spermatozoa...
  83. Webb S, Li W, Miller A. Calcium signalling during the cleavage period of zebrafish development. Philos Trans R Soc Lond B Biol Sci. 2008;363:1363-9 pubmed publisher
    ..Finally, we will present a hypothetical model that summarizes what has been suggested to be the various roles of Ca(2+) signalling during cytokinesis in teleost embryos...
  84. Johnson J, Higdon H, Boone W. Effect of human granulosa cell co-culture using standard culture media on the maturation and fertilization potential of immature human oocytes. Fertil Steril. 2008;90:1674-9 pubmed
    ..To determine whether culture of immature human oocytes with and without autologous cumulus cells (CC) in standard culture medium would provide additional oocytes for use in IVF procedures...
  85. Akiyama M, Tero A, Kobayashi R. A mathematical model of cleavage. J Theor Biol. 2010;264:84-94 pubmed publisher
    ..By considering chemotactic motion of the centrosomes, we constructed a mathematical model that describes the processes in the early stages of cleavage...
  86. Papp A, Somfai T, Tartaglione M, Varga E, Gardon J. The effect of nerve growth factor on nuclear progression of porcine oocytes during in vitro maturation and embryo development. Acta Vet Hung. 2005;53:91-101 pubmed
    ..These results suggest that NGF during IVM accelerates nuclear progression of porcine oocytes by enhancing the post-diakinetic events of meiosis...
  87. Cohen Levy J, Berdal A. [Twins: a response to the question of genetic/environmental influence on development?]. Orthod Fr. 2007;78:63-7 pubmed
    ..These natural experiences of growth phenomenon can give clues about genetic/environment interactions during development...
  88. Sansinena M, Taylor S, Taylor P, Schmidt E, Denniston R, Godke R. In vitro production of llama (Lama glama) embryos by intracytoplasmic sperm injection: effect of chemical activation treatments and culture conditions. Anim Reprod Sci. 2007;99:342-53 pubmed
    ..05). The co-culture of ICSI embryos with llama oviduct epithelial cells resulted in progression to morula (25%) and blastocyst (12%) stages; whereas, all embryos cultured in CR1aa medium arrested at the 8-16-cell developmental stage...