The Experts below are selected from a list of 5034 Experts worldwide ranked by ideXlab platform

Keith E. Latham - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of procedures for cloning by somatic cell nuclear transfer in mice.
    Methods of Molecular Biology, 2006
    Co-Authors: Young Gie Chung, Shaorong Gao, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer is a complex procedure that is dependent on correct interactions between oocyte and donor cell genome. These interactions require minimal insult to either the oocyte or the transplanted nucleus. Available data also indicate that reprogramming the donor cell genome may be slow, so that the Cloned Embryo expresses genes typical of the donor cell, and thus has different characteristics from normal Embryos. Procedures that minimize damage to the donor genome and that address the unique characteristics of the Cloned construct should enhance the efficacy of the method.

  • protease inhibitor mg132 in cloning no end to the nightmare
    Trends in Biotechnology, 2005
    Co-Authors: Shaorong Gao, Zhiming Han, Maki Kihara, Eli Y Adashi, Keith E. Latham
    Abstract:

    Nuclear reprogramming directed by the ooplasm is essential for producing Cloned animals by somatic cell nuclear transfer (SCNT). One component of the reprogramming process is the removal of somatic histone H1 variants followed by replacement by the oocyte-specific form, H1FOO [1]. Despite occurrence of this transition in 100% of SCNT constructs, Cloned Embryo development remains poor and Cloned Embryos express numerous somatic cell characteristics [2], indicating that reprogramming is slow or incomplete.

  • somatic cell like features of Cloned mouse Embryos prepared with cultured myoblast nuclei
    Biology of Reproduction, 2003
    Co-Authors: Young Gie Chung, Jean W Williams, Joan K Riley, Kelle H Moley, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer requires silencing of the donor cell gene expression program and the initiation of the Embryonic gene expression program (nuclear reprogramming). Failure to silence the donor cell program could lead to altered Embryonic phenotypes. Cloned mouse Embryos produced using myoblast nuclei fail to thrive in standard Embryo culture media but flourish in somatic cell culture media favored by the donor myoblasts themselves, forming blastocysts at a significant rate, with robust morphologies, high total cell number, and a normal allocation of cells to the inner cell mass in most Embryos. Myoblast Cloned Embryos continue expressing the GLUT4 glucose transporter, which is typically expressed in muscle but not in preimplantation stage Embryos. Myoblast clones also exhibit precocious enrichment of GLUT1 at the cell surface. Both myoblast and cumulus cell Cloned Embryos exhibit enhanced rates of glucose uptake. These observations indicate that silencing of the donor cell genome during cloning either is incomplete or occurs progressively over the course of preimplantation development. As a result, Cloned Embryos initially exhibit many somatic cell-like characteristics. Tetraploid constructs, which possess a transplanted somatic cell genome plus the oocyte-derived chromosomes, exhibit a more Embryonic-like pattern of gene expression and culture preference. We conclude that preimplantation stage Cloned Embryos have profoundly altered characteristics that are donor cell type specific and that exposure of Cloned Embryos to standard Embryo culture conditions may lead to disruptions in basic homeostasis and inhibition of a range of essential processes including further nuclear reprogramming, contributing to Cloned Embryo demise. developmental biology, early development, Embryo, gene regulation

  • somatic cell like features of Cloned mouse Embryos prepared with cultured myoblast nuclei
    Biology of Reproduction, 2003
    Co-Authors: Shaorong Gao, Young Gie Chung, Jean W Williams, Joan K Riley, Kelle H Moley, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer requires silencing of the donor cell gene expression program and the initiation of the Embryonic gene expression program (nuclear reprogramming). Failure to silence the donor cell program could lead to altered Embryonic phenotypes. Cloned mouse Embryos produced using myoblast nuclei fail to thrive in standard Embryo culture media but flourish in somatic cell culture media favored by the donor myoblasts themselves, forming blastocysts at a significant rate, with robust morphologies, high total cell number, and a normal allocation of cells to the inner cell mass in most Embryos. Myoblast Cloned Embryos continue expressing the GLUT4 glucose transporter, which is typically expressed in muscle but not in preimplantation stage Embryos. Myoblast clones also exhibit precocious enrichment of GLUT1 at the cell surface. Both myoblast and cumulus cell Cloned Embryos exhibit enhanced rates of glucose uptake. These observations indicate that silencing of the donor cell genome during cloning either is incomplete or occurs progressively over the course of preimplantation development. As a result, Cloned Embryos initially exhibit many somatic cell-like characteristics. Tetraploid constructs, which possess a transplanted somatic cell genome plus the oocyte-derived chromosomes, exhibit a more Embryonic-like pattern of gene expression and culture preference. We conclude that preimplantation stage Cloned Embryos have profoundly altered characteristics that are donor cell type specific and that exposure of Cloned Embryos to standard Embryo culture conditions may lead to disruptions in basic homeostasis and inhibition of a range of essential processes including further nuclear reprogramming, contributing to Cloned Embryo demise.

  • nuclear cytoplasmic tug of war during cloning effects of somatic cell nuclei on culture medium preferences of preimplantation Cloned mouse Embryos
    Biology of Reproduction, 2002
    Co-Authors: Young Gie Chung, Mellissa R W Mann, Marisa S Bartolomei, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer is critically dependent upon early events that occur immediately after nuclear transfer, and possibly additional events that occur in the cleaving Embryo. Embryo culture conditions have not been optimized for Cloned Embryos, and the effects of culture conditions on these early events and the successful initiation of clonal development have not been examined. To evaluate the possible effect of culture conditions on early Cloned Embryo development, we have compared a number of different culture media, either singly or in sequential combinations, for their ability to support preimplantation development of clones produced using cumulus cell nuclei. We find that glucose is beneficial during the 1-cell stage when CZB medium is employed. We also find that potassium simplex optimized medium (KSOM), which is optimized to support efficient early cleavage divisions in mouse Embryos, does not support development during the 1-cell or 2-cell stages in the Cloned Embryos as well as other media. Glucose-supplemented CZB medium (CZB-G) supports initial development to the 2-cell stage very well, but does not support later cleavage stages as well as Whittten medium or KSOM. Culturing Cloned Embryos either entirely in Whitten medium or initially in Whittens medium and then changing to KSOM at the late 4-cell/early 8-cell stage produces consistent production of blastocysts at a greater frequency than using CZB-G medium alone. The combination of Whitten medium followed by KSOM resulted in an increased number of cells per blastocyst. Because normal Embryos do not require glucose during the early cleavage stages and develop efficiently in all of the media employed, these results reveal unusual culture medium requirements that are indicative of altered physiology and metabolism in the Cloned Embryos. The relevance of this to understanding the kinetics and mechanisms of nuclear reprogramming and to the eventual improvement of the overall success in cloning is discussed.

Young Gie Chung - One of the best experts on this subject based on the ideXlab platform.

  • Embryonic and extraEmbryonic stem cell lines derived from single mouse blastomeres
    Nature, 2006
    Co-Authors: Young Gie Chung, Irina Klimanskaya, Sandy Becker, Robert Lanza, Joel Marh, Shijiang Lu, Julie Johnson, Lorraine F Meisner
    Abstract:

    The usual methods for establishing human Embryonic stem cell lines are controversial as Embryos are destroyed in the process. Two papers in this issue present different means of deriving such cells from mice without the loss of a Cloned Embryo with potential to develop. Meissner and Jaenisch describe a proof-of-principle experiment in mice based on altered nuclear transfer (ANT), a process that creates blastocysts unable to implant in the uterus. The new technique involves blocking the Cdx2 gene, but as Cdx2 might be needed for therapeutic strategies using these cells, the gene knockout is made reversible and Cdx2 can be turned back on once an Embryonic stem-cell culture is established. ANT is one alternative being discussed in US Congress hearings on the possible use of NIH funds for stem-cell research (tinyurl.com/dhwvx). Chung et al. describe a new way of deriving mouse Embryonic stem cell lines that does not disrupt the Embryo's ability to implant into the womb and develop. This procedure is based on pre-implantation genetic diagnosis (PGD) as used in fertility treatments, where Embryos are screened for genetic defects. If healthy, they are then implanted into the uterus and develop normally. If the procedure can be transferred to human Embryos already undergoing PGD, it may be possible to create banks of human Embryonic stem cell lines without additional risk to the Embryos. The most basic objection to human Embryonic stem (ES) cell research is rooted in the fact that ES cell derivation deprives Embryos of any further potential to develop into a complete human being1,2. ES cell lines are conventionally isolated from the inner cell mass of blastocysts3,4,5 and, in a few instances, from cleavage stage Embryos6,7,8,9. So far, there have been no reports in the literature of stem cell lines derived using an approach that does not require Embryo destruction. Here we report an alternative method of establishing ES cell lines—using a technique of single-cell Embryo biopsy similar to that used in pre-implantation genetic diagnosis of genetic defects10—that does not interfere with the developmental potential of Embryos. Five putative ES and seven trophoblast stem (TS) cell lines were produced from single blastomeres, which maintained normal karyotype and markers of pluripotency or TS cells for up to more than 50 passages. The ES cells differentiated into derivatives of all three germ layers in vitro and in teratomas, and showed germ line transmission. Single-blastomere-biopsied Embryos developed to term without a reduction in their developmental capacity. The ability to generate human ES cells without the destruction of ex utero Embryos would reduce or eliminate the ethical concerns of many.

  • Optimization of procedures for cloning by somatic cell nuclear transfer in mice.
    Methods of Molecular Biology, 2006
    Co-Authors: Young Gie Chung, Shaorong Gao, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer is a complex procedure that is dependent on correct interactions between oocyte and donor cell genome. These interactions require minimal insult to either the oocyte or the transplanted nucleus. Available data also indicate that reprogramming the donor cell genome may be slow, so that the Cloned Embryo expresses genes typical of the donor cell, and thus has different characteristics from normal Embryos. Procedures that minimize damage to the donor genome and that address the unique characteristics of the Cloned construct should enhance the efficacy of the method.

  • somatic cell like features of Cloned mouse Embryos prepared with cultured myoblast nuclei
    Biology of Reproduction, 2003
    Co-Authors: Young Gie Chung, Jean W Williams, Joan K Riley, Kelle H Moley, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer requires silencing of the donor cell gene expression program and the initiation of the Embryonic gene expression program (nuclear reprogramming). Failure to silence the donor cell program could lead to altered Embryonic phenotypes. Cloned mouse Embryos produced using myoblast nuclei fail to thrive in standard Embryo culture media but flourish in somatic cell culture media favored by the donor myoblasts themselves, forming blastocysts at a significant rate, with robust morphologies, high total cell number, and a normal allocation of cells to the inner cell mass in most Embryos. Myoblast Cloned Embryos continue expressing the GLUT4 glucose transporter, which is typically expressed in muscle but not in preimplantation stage Embryos. Myoblast clones also exhibit precocious enrichment of GLUT1 at the cell surface. Both myoblast and cumulus cell Cloned Embryos exhibit enhanced rates of glucose uptake. These observations indicate that silencing of the donor cell genome during cloning either is incomplete or occurs progressively over the course of preimplantation development. As a result, Cloned Embryos initially exhibit many somatic cell-like characteristics. Tetraploid constructs, which possess a transplanted somatic cell genome plus the oocyte-derived chromosomes, exhibit a more Embryonic-like pattern of gene expression and culture preference. We conclude that preimplantation stage Cloned Embryos have profoundly altered characteristics that are donor cell type specific and that exposure of Cloned Embryos to standard Embryo culture conditions may lead to disruptions in basic homeostasis and inhibition of a range of essential processes including further nuclear reprogramming, contributing to Cloned Embryo demise. developmental biology, early development, Embryo, gene regulation

  • somatic cell like features of Cloned mouse Embryos prepared with cultured myoblast nuclei
    Biology of Reproduction, 2003
    Co-Authors: Shaorong Gao, Young Gie Chung, Jean W Williams, Joan K Riley, Kelle H Moley, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer requires silencing of the donor cell gene expression program and the initiation of the Embryonic gene expression program (nuclear reprogramming). Failure to silence the donor cell program could lead to altered Embryonic phenotypes. Cloned mouse Embryos produced using myoblast nuclei fail to thrive in standard Embryo culture media but flourish in somatic cell culture media favored by the donor myoblasts themselves, forming blastocysts at a significant rate, with robust morphologies, high total cell number, and a normal allocation of cells to the inner cell mass in most Embryos. Myoblast Cloned Embryos continue expressing the GLUT4 glucose transporter, which is typically expressed in muscle but not in preimplantation stage Embryos. Myoblast clones also exhibit precocious enrichment of GLUT1 at the cell surface. Both myoblast and cumulus cell Cloned Embryos exhibit enhanced rates of glucose uptake. These observations indicate that silencing of the donor cell genome during cloning either is incomplete or occurs progressively over the course of preimplantation development. As a result, Cloned Embryos initially exhibit many somatic cell-like characteristics. Tetraploid constructs, which possess a transplanted somatic cell genome plus the oocyte-derived chromosomes, exhibit a more Embryonic-like pattern of gene expression and culture preference. We conclude that preimplantation stage Cloned Embryos have profoundly altered characteristics that are donor cell type specific and that exposure of Cloned Embryos to standard Embryo culture conditions may lead to disruptions in basic homeostasis and inhibition of a range of essential processes including further nuclear reprogramming, contributing to Cloned Embryo demise.

  • nuclear cytoplasmic tug of war during cloning effects of somatic cell nuclei on culture medium preferences of preimplantation Cloned mouse Embryos
    Biology of Reproduction, 2002
    Co-Authors: Young Gie Chung, Mellissa R W Mann, Marisa S Bartolomei, Keith E. Latham
    Abstract:

    Cloning by somatic cell nuclear transfer is critically dependent upon early events that occur immediately after nuclear transfer, and possibly additional events that occur in the cleaving Embryo. Embryo culture conditions have not been optimized for Cloned Embryos, and the effects of culture conditions on these early events and the successful initiation of clonal development have not been examined. To evaluate the possible effect of culture conditions on early Cloned Embryo development, we have compared a number of different culture media, either singly or in sequential combinations, for their ability to support preimplantation development of clones produced using cumulus cell nuclei. We find that glucose is beneficial during the 1-cell stage when CZB medium is employed. We also find that potassium simplex optimized medium (KSOM), which is optimized to support efficient early cleavage divisions in mouse Embryos, does not support development during the 1-cell or 2-cell stages in the Cloned Embryos as well as other media. Glucose-supplemented CZB medium (CZB-G) supports initial development to the 2-cell stage very well, but does not support later cleavage stages as well as Whittten medium or KSOM. Culturing Cloned Embryos either entirely in Whitten medium or initially in Whittens medium and then changing to KSOM at the late 4-cell/early 8-cell stage produces consistent production of blastocysts at a greater frequency than using CZB-G medium alone. The combination of Whitten medium followed by KSOM resulted in an increased number of cells per blastocyst. Because normal Embryos do not require glucose during the early cleavage stages and develop efficiently in all of the media employed, these results reveal unusual culture medium requirements that are indicative of altered physiology and metabolism in the Cloned Embryos. The relevance of this to understanding the kinetics and mechanisms of nuclear reprogramming and to the eventual improvement of the overall success in cloning is discussed.

Sung Keun Kang - One of the best experts on this subject based on the ideXlab platform.

  • role of messenger rna expression of platelet activating factor and its receptor in porcine in vitro fertilized and Cloned Embryo development
    Biology of Reproduction, 2004
    Co-Authors: So Hyun Lee, Daeyoung Kim, Dong Hyun Nam, Sanghwan Hyun, Gabsang Lee, Hye Soo Kim, Changkyu Lee, Sung Keun Kang
    Abstract:

    Platelet activating factor (PAF) is known as an autocrine growth/survival factor in mammalian preimplantation Embryos. This study investigated the expression of porcine PAF receptor (PAFr) mRNA and its role in porcine in vitro fertilized (IVF) or somatic cell nuclear transfer (SCNT) Embryo development. The expression of PAFr mRNA in IVF or SCNT blastocysts was shown by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis. Semiquantitative RT-PCR and Southern blot analysis demonstrated that PAFr mRNA was expressed during preimplantation Embryo development, it was highly expressed through the 2-cell to 8-cell Embryo stage, and it decreased at the morula stage. PAFr mRNA expression was detected steadily in IVF Embryos, whereas it was varied at the 2-cell, 4-cell, and blastocyst stages in SCNT Embryos. To determine the role of PAF in IVF and SCNT Embryo development, Embryos were cultured in North Carolina State University (NCSU)-23 medium supplemented with different concentrations of PAF (0, 0.037, 0.37, 3.72, or 37.2 nM). The PAF supplement significantly increased the rate of blastocyst formation in SCNT Embryos, but not in IVF Embryos. The PAF supplement for the entire 168 h of culture showed significantly higher blastocyst formation in SCNT Embryos. Upregulation of PAFr mRNA by PAF in SCNT Embryos indicated that the Embryotrophic effect of PAF was mediated through its functional receptors in SCNT Embryos. In conclusion, the present study demonstrated that PAFr mRNA was expressed in porcine IVF and SCNT Embryos, and that PAF supplement improved the developmental competence of SCNT Embryos through its specific receptors.

  • effects of exogenous hexoses on bovine in vitro fertilized and Cloned Embryo development improved blastocyst formation after glucose replacement with fructose in a serum free culture medium
    Molecular Reproduction and Development, 2003
    Co-Authors: Jean Kwun, Sung Keun Kang, Kyung Hee Chang, Jeong Mook Lim, Eunsong Lee, Byeong Chun Lee, Woosuk Hwang
    Abstract:

    To evaluate the Embryotrophic role of three hexoses (glucose, fructose, and galactose), bovine Embryos derived from somatic cell nuclear transfer (SCNT) or in vitro-fertilization (IVF) were cultured in a modified synthetic oviductal fluid (mSOF), which contained either glucose (1.5 or 5.6 mM), fructose (1.5 or 5.6 mM), or galactose (1.5 or 5.6 mM). Compared to 1.5 mM glucose, use of 1.5 mM fructose significantly enhanced blastocyst formation in both SCNT (23 vs. 33%) and IVF Embryos (26 vs. 34%), while 5.6 mM fructose did not improve blastocyst formation. Using 1.5 mM galactose did not improve blastocyst formation in SCNT Embryos (22 vs. 23%), whereas it significantly inhibited blastocyst formation in IVF Embryos (26 vs. 0%). In both SCNT and IVF Embryos, 5.6 mM glucose or galactose significantly inhibited Embryo development. In a second experiment, in glucose-free mSOF, fructose at concentrations of 0.75, 1.5, 3.0, or 5.6 mM was able to support to morula (32–42 vs. 12%) and blastocyst formation (30–38 vs. 12%) compared to 0 mM fructose. In Experiment 3, addition of fructose (1.5, 3.0, or 5.6 mM) to mSOF containing 1.5 mM glucose did not further promote blastocyst formation in SCNT Embryos compared with replacement with 1.5 mM fructose only. Replacement of glucose with 1.5 mM fructose significantly increased total blastomeres (143 vs. 123 cells) and trophectodermal (TE) cells (116 vs. 94 cells) and decreased inner cell mass (ICM) to TE cell ratio (0.24 vs. 0.31) in blastocysts, compared to 1.5 mM glucose. The combined addition of 1.5 mM fructose and glucose significantly increased ICM cell number (36.7 cells) and ICM/TE ratio (0.46). In conclusion, fructose might be a more efficient energy substrate than glucose for producing large number of transferable blastocysts derived from SCNT. Mol. Reprod. Dev. 65: 167–174, 2003. © 2003 Wiley-Liss, Inc.

  • effects of exogenous hexoses on bovine in vitro fertilized and Cloned Embryo development improved blastocyst formation after glucose replacement with fructose in a serum free culture medium
    Molecular Reproduction and Development, 2003
    Co-Authors: Jean Kwun, Sung Keun Kang, Kyung Hee Chang, Jeong Mook Lim, Eunsong Lee, Byeong Chun Lee, W S Hwang
    Abstract:

    To evaluate the Embryotrophic role of three hexoses (glucose, fructose, and galactose), bovine Embryos derived from somatic cell nuclear transfer (SCNT) or in vitro-fertilization (IVF) were cultured in a modified synthetic oviductal fluid (mSOF), which contained either glucose (1.5 or 5.6 mM), fructose (1.5 or 5.6 mM), or galactose (1.5 or 5.6 mM). Compared to 1.5 mM glucose, use of 1.5 mM fructose significantly enhanced blastocyst formation in both SCNT (23 vs. 33%) and IVF Embryos (26 vs. 34%), while 5.6 mM fructose did not improve blastocyst formation. Using 1.5 mM galactose did not improve blastocyst formation in SCNT Embryos (22 vs. 23%), whereas it significantly inhibited blastocyst formation in IVF Embryos (26 vs. 0%). In both SCNT and IVF Embryos, 5.6 mM glucose or galactose significantly inhibited Embryo development. In a second experiment, in glucose-free mSOF, fructose at concentrations of 0.75, 1.5, 3.0, or 5.6 mM was able to support to morula (32-42 vs. 12%) and blastocyst formation (30-38 vs. 12%) compared to 0 mM fructose. In Experiment 3, addition of fructose (1.5, 3.0, or 5.6 mM) to mSOF containing 1.5 mM glucose did not further promote blastocyst formation in SCNT Embryos compared with replacement with 1.5 mM fructose only. Replacement of glucose with 1.5 mM fructose significantly increased total blastomeres (143 vs. 123 cells) and trophectodermal (TE) cells (116 vs. 94 cells) and decreased inner cell mass (ICM) to TE cell ratio (0.24 vs. 0.31) in blastocysts, compared to 1.5 mM glucose. The combined addition of 1.5 mM fructose and glucose significantly increased ICM cell number (36.7 cells) and ICM/TE ratio (0.46). In conclusion, fructose might be a more efficient energy substrate than glucose for producing large number of transferable blastocysts derived from SCNT.

Robert Lanza - One of the best experts on this subject based on the ideXlab platform.

  • Embryonic and extraEmbryonic stem cell lines derived from single mouse blastomeres
    Nature, 2006
    Co-Authors: Young Gie Chung, Irina Klimanskaya, Sandy Becker, Robert Lanza, Joel Marh, Shijiang Lu, Julie Johnson, Lorraine F Meisner
    Abstract:

    The usual methods for establishing human Embryonic stem cell lines are controversial as Embryos are destroyed in the process. Two papers in this issue present different means of deriving such cells from mice without the loss of a Cloned Embryo with potential to develop. Meissner and Jaenisch describe a proof-of-principle experiment in mice based on altered nuclear transfer (ANT), a process that creates blastocysts unable to implant in the uterus. The new technique involves blocking the Cdx2 gene, but as Cdx2 might be needed for therapeutic strategies using these cells, the gene knockout is made reversible and Cdx2 can be turned back on once an Embryonic stem-cell culture is established. ANT is one alternative being discussed in US Congress hearings on the possible use of NIH funds for stem-cell research (tinyurl.com/dhwvx). Chung et al. describe a new way of deriving mouse Embryonic stem cell lines that does not disrupt the Embryo's ability to implant into the womb and develop. This procedure is based on pre-implantation genetic diagnosis (PGD) as used in fertility treatments, where Embryos are screened for genetic defects. If healthy, they are then implanted into the uterus and develop normally. If the procedure can be transferred to human Embryos already undergoing PGD, it may be possible to create banks of human Embryonic stem cell lines without additional risk to the Embryos. The most basic objection to human Embryonic stem (ES) cell research is rooted in the fact that ES cell derivation deprives Embryos of any further potential to develop into a complete human being1,2. ES cell lines are conventionally isolated from the inner cell mass of blastocysts3,4,5 and, in a few instances, from cleavage stage Embryos6,7,8,9. So far, there have been no reports in the literature of stem cell lines derived using an approach that does not require Embryo destruction. Here we report an alternative method of establishing ES cell lines—using a technique of single-cell Embryo biopsy similar to that used in pre-implantation genetic diagnosis of genetic defects10—that does not interfere with the developmental potential of Embryos. Five putative ES and seven trophoblast stem (TS) cell lines were produced from single blastomeres, which maintained normal karyotype and markers of pluripotency or TS cells for up to more than 50 passages. The ES cells differentiated into derivatives of all three germ layers in vitro and in teratomas, and showed germ line transmission. Single-blastomere-biopsied Embryos developed to term without a reduction in their developmental capacity. The ability to generate human ES cells without the destruction of ex utero Embryos would reduce or eliminate the ethical concerns of many.

Jean Kwun - One of the best experts on this subject based on the ideXlab platform.

  • effects of exogenous hexoses on bovine in vitro fertilized and Cloned Embryo development improved blastocyst formation after glucose replacement with fructose in a serum free culture medium
    Molecular Reproduction and Development, 2003
    Co-Authors: Jean Kwun, Sung Keun Kang, Kyung Hee Chang, Jeong Mook Lim, Eunsong Lee, Byeong Chun Lee, Woosuk Hwang
    Abstract:

    To evaluate the Embryotrophic role of three hexoses (glucose, fructose, and galactose), bovine Embryos derived from somatic cell nuclear transfer (SCNT) or in vitro-fertilization (IVF) were cultured in a modified synthetic oviductal fluid (mSOF), which contained either glucose (1.5 or 5.6 mM), fructose (1.5 or 5.6 mM), or galactose (1.5 or 5.6 mM). Compared to 1.5 mM glucose, use of 1.5 mM fructose significantly enhanced blastocyst formation in both SCNT (23 vs. 33%) and IVF Embryos (26 vs. 34%), while 5.6 mM fructose did not improve blastocyst formation. Using 1.5 mM galactose did not improve blastocyst formation in SCNT Embryos (22 vs. 23%), whereas it significantly inhibited blastocyst formation in IVF Embryos (26 vs. 0%). In both SCNT and IVF Embryos, 5.6 mM glucose or galactose significantly inhibited Embryo development. In a second experiment, in glucose-free mSOF, fructose at concentrations of 0.75, 1.5, 3.0, or 5.6 mM was able to support to morula (32–42 vs. 12%) and blastocyst formation (30–38 vs. 12%) compared to 0 mM fructose. In Experiment 3, addition of fructose (1.5, 3.0, or 5.6 mM) to mSOF containing 1.5 mM glucose did not further promote blastocyst formation in SCNT Embryos compared with replacement with 1.5 mM fructose only. Replacement of glucose with 1.5 mM fructose significantly increased total blastomeres (143 vs. 123 cells) and trophectodermal (TE) cells (116 vs. 94 cells) and decreased inner cell mass (ICM) to TE cell ratio (0.24 vs. 0.31) in blastocysts, compared to 1.5 mM glucose. The combined addition of 1.5 mM fructose and glucose significantly increased ICM cell number (36.7 cells) and ICM/TE ratio (0.46). In conclusion, fructose might be a more efficient energy substrate than glucose for producing large number of transferable blastocysts derived from SCNT. Mol. Reprod. Dev. 65: 167–174, 2003. © 2003 Wiley-Liss, Inc.

  • effects of exogenous hexoses on bovine in vitro fertilized and Cloned Embryo development improved blastocyst formation after glucose replacement with fructose in a serum free culture medium
    Molecular Reproduction and Development, 2003
    Co-Authors: Jean Kwun, Sung Keun Kang, Kyung Hee Chang, Jeong Mook Lim, Eunsong Lee, Byeong Chun Lee, W S Hwang
    Abstract:

    To evaluate the Embryotrophic role of three hexoses (glucose, fructose, and galactose), bovine Embryos derived from somatic cell nuclear transfer (SCNT) or in vitro-fertilization (IVF) were cultured in a modified synthetic oviductal fluid (mSOF), which contained either glucose (1.5 or 5.6 mM), fructose (1.5 or 5.6 mM), or galactose (1.5 or 5.6 mM). Compared to 1.5 mM glucose, use of 1.5 mM fructose significantly enhanced blastocyst formation in both SCNT (23 vs. 33%) and IVF Embryos (26 vs. 34%), while 5.6 mM fructose did not improve blastocyst formation. Using 1.5 mM galactose did not improve blastocyst formation in SCNT Embryos (22 vs. 23%), whereas it significantly inhibited blastocyst formation in IVF Embryos (26 vs. 0%). In both SCNT and IVF Embryos, 5.6 mM glucose or galactose significantly inhibited Embryo development. In a second experiment, in glucose-free mSOF, fructose at concentrations of 0.75, 1.5, 3.0, or 5.6 mM was able to support to morula (32-42 vs. 12%) and blastocyst formation (30-38 vs. 12%) compared to 0 mM fructose. In Experiment 3, addition of fructose (1.5, 3.0, or 5.6 mM) to mSOF containing 1.5 mM glucose did not further promote blastocyst formation in SCNT Embryos compared with replacement with 1.5 mM fructose only. Replacement of glucose with 1.5 mM fructose significantly increased total blastomeres (143 vs. 123 cells) and trophectodermal (TE) cells (116 vs. 94 cells) and decreased inner cell mass (ICM) to TE cell ratio (0.24 vs. 0.31) in blastocysts, compared to 1.5 mM glucose. The combined addition of 1.5 mM fructose and glucose significantly increased ICM cell number (36.7 cells) and ICM/TE ratio (0.46). In conclusion, fructose might be a more efficient energy substrate than glucose for producing large number of transferable blastocysts derived from SCNT.