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Journal Article•DOI•

Preimplantation development of in vitro-matured and in vitro-fertilized ovine zygotes: comparison between coculture on oviduct epithelial cell monolayers and culture under low oxygen atmosphere.

01 Apr 1994-Biology of Reproduction (Society for the Study of Reproduction)-Vol. 50, Iss: 4, pp 715-724
TL;DR: Two distinct culture environments are characterized, each capable of supporting the development of high frequencies of unselected IVMF zygotes to the blastocyst stage in vitro, and survival of the embryo under a reduced oxygen atmosphere is investigated.
Abstract: The roles of medium composition, serum source, embryo coculture, and culture under low O2 conditions on the development of in vitro-matured and in vitro-fertilized (IVMF) ovine zygotes were investigated in three separate experiments. In the first experiment, the proportion of cocultured IVMF zygotes developing to the blastocyst stage was significantly higher (38.0% vs. 3.5%; p < 0.05) than that of non-cocultured zygotes treated within three embryo culture media (TCM-199 + 10% fetal bovine serum [FBS]; bicarbonate-buffered, glucose-free synthetic oviduct fluid medium [mod-SOFM] + 10% FBS; and bicarbonate-buffered BSA-free Tyrode's salt solution [mod-TALP] + 10% FBS) under a 5% CO2 atmosphere in air. In a second experiment, a significantly higher (p < 0.05) proportion of cocultured zygotes placed in TCM-199 medium survived to the blastocyst stage (37.4% blastocysts vs. 23.4% in mod-SOFM). No significant effect of serum (FBS vs. human serum [HS]) was observed on embryonic development, but coculture was confirmed to exert a significant influence on development to the blastocyst stage. In the final experiment, survival of the embryo under a reduced oxygen (5% CO2:5% O2:90% N2) atmosphere was investigated. In contrast to results in the initial experiments, embryonic survival was significantly higher (p < 0.05) in the non-cocultured treatment groups (21.9% blastocysts vs. 0.4% for cocultured zygotes). Serum source also had a significant (p < 0.05) influence upon the development of non-cocultured zygotes: 32.3% of zygotes cultured with HS progressed to the blastocyst stage vs. 11.5% of zygotes cultured in FBS-supplemented medium. These results have characterized two distinct culture environments, each capable of supporting the development of high frequencies of unselected IVMF zygotes to the blastocyst stage in vitro.

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Citations
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Journal Article•DOI•
TL;DR: The role of oxidative stress in the etiology and pathophysiology of human IVF is summarized, as well as considering different strategies and approaches to be followed to prevent the harmful effects of oxidative Stress on IVF.
Abstract: Gametes and embryos are natural sources of free radicals. When manipulated in vitro during assisted reproductive techniques, these cells run the risk of generating and being exposed to supraphysiological levels of reactive oxygen species. It is therefore clear that free radicals and oxidative stress can have a significant impact on IVF outcome. This review summarizes the role of oxidative stress in the etiology and pathophysiology of human IVF, as well as considering different strategies and approaches to be followed to prevent the harmful effects of oxidative stress on IVF.

124 citations

Journal Article•DOI•
TL;DR: This is the first report of live foals resulting from in vitro fertilization (via ICSI) of in vitro matured oocytes recovered from pregnant mares using an efficient, repeatable transvaginal ultrasound-guided procedure.

119 citations

Journal Article•DOI•
TL;DR: Further work to investigate interactions between oxygen and other signaling pathways such as pH and Ca(2+), mitochondria and metabolism is required, as well as exposure of embryos at different time points, to determine the mechanisms that control preimplantation development, the interactions of a range of stimuli and to establish culture procedures that support optimal development and minimize risks to health.

117 citations


Cites background from "Preimplantation development of in v..."

  • ..., 1991), pig (Watson et al., 1994), rabbit (Li and Foote, 1993) and mouse (Umaoka et al....

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Journal Article•DOI•
TL;DR: The results expand on previous work showing that oocytes with early signs of atresia have good development potential and indicate that transcriptional activity was determined by the interval after fertilization rather than the number of cell cycles.

114 citations

Journal Article•DOI•
TL;DR: Primary ovine oviduct cell cultures express the transcripts for IGF-II, IGF-I, TGF alpha, bFGF, T GF beta 1, and the receptors for insulin and IGF-i, suggesting that paracrine growth factor circuits may exist between the Oviduct epithelium and the early ovine embryo.
Abstract: The reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the patterns of expression for several growth factor ligand and receptor genes during ovine preimplantation development. Transcripts for insulin-like growth factor (IGF)-I, IGF-II, and the receptors for insulin and IGF-I were detected throughout ovine preimplantation development from the 1-cell to the blastocyst stage. Transforming growth factor alpha (TGF alpha) transcripts were also detected throughout ovine preimplantation development. The mRNAs encoding basic fibroblast growth factor (bFGF) were detected in all stages of the ovine preimplantation embryo, although the relative abundance of this transcript consistently decreased from the 1-cell to the blastocyst stage, suggesting that it may represent a maternal transcript in early sheep embryos. Transcripts encoding ovine trophoblast protein (oTP) were detected only within blastocyst-stage embryos. Primary ovine oviduct cell cultures express the transcripts for IGF-II, IGF-I, TGF alpha, bFGF, TGF beta 1, and the receptors for insulin and IGF-I, suggesting that paracrine growth factor circuits may exist between the oviduct epithelium and the early ovine embryo. Transcripts for insulin, epidermal growth factor (EGF), and nerve growth factor (NGF) were not detected in any stage of the ovine preimplantation embryo or within the oviduct cell preparations. The expression of growth factor transcripts very early in mammalian development would predict that these molecules fulfil a necessary role(s) in supporting the progression of early embryos through the preimplantation interval. Our future efforts will be directed to understanding the nature of these putative regulatory pathways.

114 citations


Cites methods from "Preimplantation development of in v..."

  • ...[48] were employed in the production of preimplantation ovine embryos from follicular aspirates obtained from slaughterhouse ovaries....

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  • ...The methods employed in the establishment of these cultures were as previously described [12,48]....

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References
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Journal Article•DOI•
Peter McCullagh1•
TL;DR: In this article, a general class of regression models for ordinal data is developed and discussed, which utilize the ordinal nature of the data by describing various modes of stochastic ordering and this eliminates the need for assigning scores or otherwise assuming cardinality instead of ordinality.
Abstract: SUMMARY A general class of regression models for ordinal data is developed and discussed. These models utilize the ordinal nature of the data by describing various modes of stochastic ordering and this eliminates the need for assigning scores or otherwise assuming cardinality instead of ordinality. Two models in particular, the proportional odds and the proportional hazards models are likely to be most useful in practice because of the simplicity of their interpretation. These linear models are shown to be multivariate extensions of generalized linear models. Extensions to non-linear models are discussed and it is shown that even here the method of iteratively reweighted least squares converges to the maximum likelihood estimate, a property which greatly simplifies the necessary computation. Applications are discussed with the aid of examples.

3,647 citations

Journal Article•DOI•
TL;DR: A procedure to obtain high and repeatable fertilization frequencies for bovine in vitro fertilization (IVF) with frozen-thawed sperm was developed and Heparin was the most important factor in increasing IVF frequencies.

1,165 citations

Journal Article•DOI•
TL;DR: The Two Faces of Oxygen Molecular oxygen is both benign and malign and the superoxide dismutases, by catalytically scavenging 0;, provide a defense against it and against any reactive radical species which can be derived from it.
Abstract: The Two Faces of Oxygen Molecular oxygen is both benign and malign On the one hand it provides enormous advantages and on the other it imposes a universal toxicity This toxicity is largely due to the intermediates of oxygen reduction, ie 0;, H202, and OH·, and any organism that avails itself of the benefits of oxygen does so at the cost of maintaining an elaborate system of defenses against these intermediates We will here concern ourselves with the superoxide dismutases which, by catalytically scavenging 0;, provide a defense against it and against any reactive radical species which can be derived from it

1,139 citations

Journal Article•DOI•
TL;DR: The in-vitro development of 1-cell embryos beyond the 2-cell stage in response to the removal of glucose and the addition of glutamine to the culture medium suggests that glucose may block some essential metabolic process, and that glutamine may be a preferred energy substrate during early development for these mouse embryos.
Abstract: One-cell CF-1 x B6SJLF1/J embryos, which usually exhibit a 2-cell block to development in vitro, have been cultured to the blastocyst stage using CZB medium and a glucose washing procedure. CZB medium is a further modification of modified BMOC-2 containing an increased lactate/pyruvate ratio of 116, 1 mM-glutamine and 0.1 mM-EDTA but lacking glucose. Continuous culture of one-cell embryos in CZB medium allowed 83% of embryos to develop beyond the 2-cell stage of which 63% were morulae at 72 h of culture, but blastocysts did not develop. However, washing embryos into CZB medium containing glucose after 48 h of culture (3-4-cell stage) was sufficient to allow development to proceed, with 48% of embryos reaching the blastocyst stage by 96 h of culture. Exposure of embryos to glucose was only necessary from the 3-4-cell stage through the early morula stage since washing back into medium CZB without glucose at 72 h of culture still promoted the development of 50% of embryos to the blastocyst stage. The presence of glucose in this medium for the first 48 h of culture (1-cell to 4-cell stage) was detrimental to embryo development. Glutamine, however, exerted a beneficial effect on embryo development from the 1-cell to the 4-cell stage although its presence was not required for development to proceed during the final 48 h of culture. Blastocysts which developed under optimum conditions contained an average of 33.7 total cells. The in-vitro development of 1-cell embryos beyond the 2-cell stage in response to the removal of glucose and the addition of glutamine to the culture medium suggests that glucose may block some essential metabolic process, and that glutamine may be a preferred energy substrate during early development for these mouse embryos.

1,119 citations

Journal Article•DOI•
TL;DR: This communication describes the successful culture of one-cell to eight-cell sheep ova and one- cell and eight- cell cattle ova to the morula and blastocyst stages and reports a high embryo survival after transfer of cultured Ova to recipient animals.
Abstract: Fertilized sheep and cattle ova have not been reported to develop readily during culture in vitro. Up to 60% of sheep morulae develop normally during culture (Moor & Cragle, 1971) but earlier cleavage stages undergo limited development (Hancock, 1963; Kraemer, 1966; Tervit & McDonald, 1969; Moore, 1970) and it has been suggested that there is a block to development in vitro at the eightto twelve-cell stage (Wintenberger, Dauzier & Thibault, 1953). Only the early cleavage stages of cattle ova have been cultured and these have not been reported to develop beyond the twenty-four-cell stage in vitro (Thibault, 1966; Brinster, 1968; Sreenan, 1968; Sreenan, Scanlon & Gordon, 1968). This communication describes the successful culture of one-cell to eight-cell sheep ova and one-cell and eight-cell cattle ova to the morula and blastocyst stages and reports a high embryo survival after transfer of cultured ova to recipient animals.

1,009 citations