@article{sommer_estrada_collins_bedell_alexander_yang_hughes_mir_gilger_grob_et al._2011, title={Production of ELOVL4 transgenic pigs: a large animal model for Stargardt-like macular degeneration}, volume={95}, ISSN={0007-1161}, url={http://dx.doi.org/10.1136/bjophthalmol-2011-300417}, DOI={10.1136/bjophthalmol-2011-300417}, abstractNote={Background Truncation mutations in the elongation of very long chain fatty acids-4 (AF277094, MIM #605512) (ELOVL4) gene cause Stargardt-like macular dystrophy type 3 (STGD3). Mice expressing truncated ELOVL4 develop rapid retinal degeneration, but are poor STGD3 models since mice lack a macula. Photoreceptor topography in the pig retina is more similar to that in humans as it includes the cone rich, macula-like area centralis. The authors generated transgenic pigs expressing human disease-causing ELOVL4 mutations to better model the pathobiology of this macular disease. Methods Pronuclear DNA microinjection and somatic cell nuclear transfer were used to produce transgenic pigs for two different ELOVL4 mutations: the 5 base pair deletion (5 bpdel) and the 270 stop mutation (Y270terEYFP). Retinal transgene expression, morphology and electrophysiology were examined. Results The authors obtained four lines of Y270terEYFP and one line of 5 bpdel transgenic animals. Direct fluorescence microscopy indicated that the Y270terEYFP protein is expressed in photoreceptors and mislocalised within the cell. Immunohistochemical examination of transgenic pigs showed photoreceptor loss and disorganised inner and outer segments. Electroretinography demonstrated diminished responses in both transgenic models. Conclusions These transgenic pigs provide unique animal models for examining macular degeneration and STGD3 pathogenesis.}, number={12}, journal={British Journal of Ophthalmology}, publisher={BMJ}, author={Sommer, J. R. and Estrada, J. L. and Collins, E. B. and Bedell, M. and Alexander, C. A. and Yang, Z. and Hughes, G. and Mir, B. and Gilger, B. C. and Grob, S. and et al.}, year={2011}, month={Aug}, pages={1749–1754} }
 @article{mccalla-martin_chen_linder_estrada_piedrahita_2010, title={Varying phenotypes in swine versus murine transgenic models constitutively expressing the same human Sonic hedgehog transcriptional activator, K5-HGLI2ΔN}, volume={19}, ISSN={0962-8819 1573-9368}, url={http://dx.doi.org/10.1007/s11248-010-9362-0}, DOI={10.1007/s11248-010-9362-0}, abstractNote={This study was undertaken to characterize the effects of constitutive expression of the hedgehog transcriptional activator, Gli2, in porcine skin. The keratinocyte-specific human transgene, K5-hGli2 Delta N, was used to produce transgenic porcine lines via somatic cell nuclear transfer techniques. In mice, K5-hGli2 Delta N induces epithelial downgrowths resembling basal cell carcinomas. Our porcine model also developed these basal cell carcinoma-like lesions, however gross tumor development was not appreciated. In contrast to the murine model, diffuse epidermal changes as well as susceptibility to cutaneous infections were seen in the swine model. Histologic analysis of transgenic piglets revealed generalized epidermal changes including: epidermal hyperplasia (acanthosis), elongated rete ridges, parakeratotic hyperkeratosis, epidermal neutrophilic infiltration, capillary loop dilation and hypogranulosis. By 2 weeks of age, the transgenic piglets developed erythematic and edematous lesions at high contact epidermal areas and extensor surfaces of distal limb joints. Despite antibiotic treatment, these lesions progressed to a deep bacterial pyoderma and pigs died or were euthanized within weeks of birth. Non-transgenic littermates were phenotypically normal by gross and histological analysis. In summary, constitutive expression of the human hGli2 Delta N in keratinocytes, results in cutaneous changes that have not been reported in the K5-hGli2 Delta N murine model. These findings indicate a need for a multiple species animal model approach in order to better understand the role of Gli2 in mammalian skin.}, number={5}, journal={Transgenic Research}, publisher={Springer Science and Business Media LLC}, author={McCalla-Martin, Amy C. and Chen, Xiaoxin and Linder, Keith E. and Estrada, Jose L. and Piedrahita, Jorge A.}, year={2010}, month={Jan}, pages={869–887} }
 @article{lee_estrada_piedrahita_2008, title={A comparative study on the efficiency of two enucleation methods in pig somatic cell nuclear transfer: Effects of the squeezing and the aspiration methods}, volume={19}, ISSN={["1532-2378"]}, DOI={10.1080/10495390701839264}, abstractNote={In this study, two enucleation methods, the squeezing and the aspiration methods, were compared. The efficiency of these two methods to enucleate pig oocytes and the in vitro and in vivo viability of somatic cell nuclear transfer (SCNT) pig embryos, were evaluated. In the squeezing method, the zona pellucida was partially dissected and a small amount of cytoplasm containing metaphase II (MII) chromosomes and the first polar body (PB) were pushed out. In the aspiration method, the PB and MII chromosomes were aspirated using a beveled micropipette. After injection of fetal fibroblasts into the perivitelline space, reconstructed oocytes were fused and activated electrically, and then cultured in vitro for 6 days or transferred to surrogates. The squeezing method resulted in a higher proportion of degenerated oocytes than the aspiration method (14% vs. 5%). The squeezing method took longer to enucleate 100 oocytes (306 minutes) than the aspirating method (113 minutes). Fusion rate (72–78%) and cleavage rate (67%) were not influenced by the enucleation method but blastocyst formation was improved (P < 0.05) in oocytes enucleated by the aspiration method (5 vs. 9%). When SCNT embryos were transferred to recipients, pregnancy rates to term were similar (27%, 3/11 and 27%, 3/11) in both methods with the birth of 10 piglets/3 litters and 16 piglets/3 litters in the squeezing and the aspiration methods, respectively. Our results indicate that the aspiration method for oocyte enucleation is more efficient than the squeezing method in producing a large number of pig SCNT embryos with normal in vivo viability.}, number={2}, journal={ANIMAL BIOTECHNOLOGY}, author={Lee, Eunsong and Estrada, Jose and Piedrahita, Jorge A.}, year={2008}, pages={71–79} }
 @article{estrada_collins_york_bischoff_sommer_tsai_petters_piedrahita_2008, title={Successful cloning of the Yucatan minipig using commercial/occidental breeds as oocyte donors and embryo recipients}, volume={10}, ISSN={["1536-2302"]}, DOI={10.1089/clo.2008.0005}, abstractNote={The widespread application of porcine SCNT to biomedical research is being hampered by the large adult size (300-600 lbs) of the commercial breeds commonly used for SCNT. The Yucatan minipig, in contrast, has an adult weight of 140-150 lbs and a long history of utility in biomedical research. In order to combine the wide availability of commercial swine with the biomedical value of the Yucatan minipig, we utilized SCNT using the Yucatan as nuclear donors and commercial swine as both oocyte donors and recipients. Of six recipient gilts receiving 631 SCNT embryos, three went to term and delivered seven piglets, four of which survived to adulthood. Additionally, we obtained fetal fibroblasts from a cloned Yucatan and used them for a second round of SCNT. Of three recipients receiving 315 reconstructed embryos, one went to term and delivered three piglets, one of which survived to adulthood. Both microsatellite and D-loop sequence analysis confirmed that all of the piglets generated were nuclear-mitochondrial hybrids carrying Yucatan nuclear DNA and commercial breed mitochondrial DNA. This report shows that it is possible to produce viable Yucatan SCNT clones and opens up the possibility of developing valuable biomedical models in this porcine breed.}, number={2}, journal={CLONING AND STEM CELLS}, author={Estrada, Jose L. and Collins, Bruce and York, Abby and Bischoff, Steve and Sommer, Jeff and Tsai, Shengdar and Petters, Robert M. and Piedrahita, Jorge A.}, year={2008}, month={Jun}, pages={287–296} }
 @misc{miguel_agustin_jose_2007, title={Growth factors in the follicular development, embryonic early and implantation. Implications in the production of bovine embryos}, volume={12}, number={1}, journal={Revista MVZ Cordoba}, author={Miguel, P. J. and Agustin, G. O. and Jose, E. L.}, year={2007}, pages={942–954} }
 @article{estrada_sommer_collins_mir_martin_york_petters_piedrahita_2007, title={Swine generated by somatic cell nuclear transfer have increased incidence of intrauterine growth restriction (IUGR)}, volume={9}, ISSN={["1536-2302"]}, DOI={10.1089/clo.2006.0079}, abstractNote={While somatic cell nuclear transfer (SCNT) has been successful in several species, many pregnancies are lost and anomalies are found in fetal and perinatal stages. In this study SCNT and artificial inseminations (AI) populations were compared for litter size, average birth weight, piglets alive at birth, stillborn, mummies, dead at the first week, intrauterine growth restriction (IUGR) and large for gestational age (LGA). Twenty-three SCNT litters (143 individuals) were compared to 112 AI litters (1300 individuals). Litter size average was 11.5 for AI and 6.2 for SCNT. Litter weight and average birth weight adjusted by litter size were significantly (p < 0.05) higher in AI than in SCNT litters. The SCNT population had a significant (p < 0.01) increase in the number of IUGRs per litter with LSmeans 7.2 +/- 1.4 versus 19.4 +/- 3.5 and means 8.0 +/- 10.8 versus 15.5 +/- 24.5 for AI and SCNT, respectively. Additionally, there was a trend for higher postnatal mortality and stillbirths in the SCNT population. These findings demonstrate that there are some differences between SCNT-derived and AI litters. SCNT-derived pigs are excellent models to study epigenetic factors and genes involved in IUGRs, and to develop effective means to improve fetal growth in humans and animals.}, number={2}, journal={CLONING AND STEM CELLS}, author={Estrada, Jose and Sommer, Jeffrey and Collins, Bruce and Mir, Bashir and Martin, Amy and York, Abby and Petters, Robert M. and Piedrahita, Jorge A.}, year={2007}, pages={229–236} }
 @article{sommer_collins_estrada_petters_2007, title={Synchronization and superovulation of mature cycling gilts for the collection of pronuclear stage embryos}, volume={100}, ISSN={["1873-2232"]}, DOI={10.1016/j.anireprosci.2006.10.010}, abstractNote={An efficient protocol was developed to synchronize and superovulate mature pigs for the collection of pronuclear stage embryos suitable for DNA microinjection. A timed and coordinated regimen of Lutalyse, PG600 and Chorulon along with daily checking for estrus allowed synchronization of groups of gilts having estrous cycles at regular intervals. Pigs 10-16 days after the beginning of standing estrus have been successfully synchronized into estrus using this protocol. A standard dose of each drug was used independent of size or age of the animal. One protocol averaged 38.9 ovulations and 31.1 one-cell embryos recovered per animal.}, number={3-4}, journal={ANIMAL REPRODUCTION SCIENCE}, author={Sommer, Jeffrey R. and Collins, E. Bruce and Estrada, Jose L. and Petters, Robert M.}, year={2007}, month={Aug}, pages={402–410} }
 @article{tsai_mir_martin_estrada_bischoff_hsieh_cassady_freking_nonneman_rohrer_et al._2006, title={Detection of transcriptional difference of porcine imprinted genes using different microarray platforms}, volume={7}, journal={BMC Genomics}, author={Tsai, S. and Mir, B. and Martin, A. C. and Estrada, J. L. and Bischoff, S. R. and Hsieh, W. P. and Cassady, J. P. and Freking, B. A. and Nonneman, D. J. and Rohrer, G. A. and et al.}, year={2006} }
 @article{estrada_jones_johnson_petters_1991, title={Effect of insulin-like growth factor-I on protein synthesis in porcine embryonic discs cultured in vitro}, volume={93}, DOI={10.1530/jrf.0.0930053}, abstractNote={Porcine embryos at Day 13 (Day 0 = first day of oestrus) were collected surgically and embryonic discs were isolated microsurgically. The discs were washed and cultured in Dulbecco's modified Eagle's medium without serum, with either 14C-leucine alone or 14C-leucine plus insulin-like growth factor-I (IGF-I) (100 ng/ml) at 37 degrees C for 48 h in 5% CO2 in air. After incubation, discs were morphologically evaluated, frozen in liquid nitrogen and stored at -70 degrees C. No statistical differences in morphology were observed between embryonic discs cultured in medium with IGF-I and those cultured in medium alone (control). Although more radioactivity was incorporated by embryonic discs in the presence of IGF-I than by those cultured in medium without the growth factor, the difference between the two groups was not significant. From two-dimensional gel electrophoresis, it was observed that IGF-I selectively stimulated the synthesis of four new proteins with Mr of 24,000, 70,000, 77,000 and 95,000, respectively and pI between 5.5 and 6.5. At least 90% of the other proteins in the gels was synthesized in greater amount by embryonic discs cultured in the presence of IGF-I than in the controls. These results show that IGF-I can stimulate protein synthesis in pig embryonic discs cultured in vitro and suggest that this growth factor may play an important role in regulating early development.}, number={1}, journal={Journal of Reproduction & Fertility}, author={Estrada, J. L. and Jones, E. E. and Johnson, B. H. and Petters, R. M.}, year={1991}, pages={53} }