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| 1 | Asynchronous Embryo Transfer in Sheep:Lack of Survival in Progestinized Recipient Ewes显示文摘Synchronization of development between the embryo and uterus is required for successful pregnancy establishment.Transfer of early embryos requires synchrony with the recipient uterus of 2 days or less in sheep,because asynchrony of 3 days or more results in failure of pregnancy recognition signaling for maintenance of corpus luteum (CL) and progesterone (P4) production and/or uterine support of the embryo.The objective was to determine if P4 treatment of recipient ewes would obviate the need for pregnancy recognition signaling and maintain a uterine environment conducive to embryo survival after asynchronous transfer,thereby establishing a universal recipient.Embryos (morulae/blastocysts) were recovered on day 6 from super-ovulated donor ewes.Recipient ewes received 25 mg P4 daily from day 6 post-estrus until 60 days after embryo transfer.Embryos were transferred into recipients on day 6,9,12,18,or 30 post-estrus.The pregnancy rate on day 22 post-transfer was 60% for synchronous transfers to day 6 ewes,44% and 22% for asynchronous transfers to day 9 and 12 ewes,and 0% for asynchronous transfers to day 18 and 30 ewes.On day 39 post-transfer,pregnancy rates remained 60% for day 6 ewes,33% for day 9 ewes,and 0% for day 12,18,and 30 ewes.The P4 treatment did extend the window of uterine receptivity to early embryos in ewes by one day,but did not create a universal recipient.Available results support the idea that a window of uterine receptivity to the conceptus exists in sheep that is independent of pregnancy recognition signaling. | M.Carey Satterfield Thomas E.Spencer | 2011 | Journal of Animal Science and Biotechnology2011，2，1： | 5 |
| 2 | A comparative study of leaf nutrient concentrations in a regional herbaceous flora显示文摘 | KENTHOMPSON JOHN A.PARKINSON STUART R.BAND RITA E.SPENCER | 2008 | New Phytologist2008，，4： | 3 |
| 3 | Word‐Learning Skills of Deaf Preschoolers: The Development of Novel Mapping and Rapid Word‐Learning Strategies显示文摘 | Amy R.Lederberg Amy K.Prezbindowski Patricia E.Spencer | 2003 | Child Development2003，，6： | 1 |
| 4 | Retinoid X receptor α downregulation is required for tail and caudal spinal cord regeneration in the adult newt显示文摘Some adult vertebrate species,such as newts,axolotls and zebrafish,have the ability to regenerate their central nervous system(CNS).However,the factors that establish a permissive CNS environment for correct morphological and functional regeneration in these species are not well understood.Recent evidence supports a role for retinoid signaling in the intrinsic ability of neurons,in these regeneration-competent species,to regrow after CNS injury.Previously,we demonstrated that a specific retinoic acid receptor(RAR)subtype,RARβ,mediates the effects of endogenous retinoic acid(RA)on neuronal growth and guidance in the adult newt CNS after injury.Here,we now examine the expression of the retinoid X receptor RXRα(a potential heterodimeric transcriptional regulator with RARβ),in newt tail and spinal cord regeneration.We show that at 21 days post-amputation(dpa),RXRαis expressed at temporally distinct periods and in non-overlapping spatial domains compared to RARβ.Whereas RARβprotein levels increase,RXRαproteins level decrease by 21 dpa.A selective agonist for RXR,SR11237,prevents both this downregulation of RXRαand upregulation of RARβand inhibits tail and caudal spinal cord regeneration.Moreover,treatment with a selective antagonist for RARβ,LE135,inhibits regeneration with the same morphological consequences as treatment with SR11237.Interestingly,LE135 treatment also inhibits the normal downregulation of RXRαin tail and spinal cord tissues at 21 dpa.These results reveal a previously unidentified,indirect regulatory feedback loop between these two receptor subtypes in regulating the regeneration of tail and spinal cord tissues in this regeneration-competent newt. | Sarah E.Walker Rachel Nottrodt Lucas Maddalena Christopher Carter Gaynor E.Spencer Robert L.Carlone | 2018 | Neural Regeneration Research2018，13，6： | 1 |
| 5 | Fine-tuning the response of growth cones to guidance cues: a perspective on the role of microRNAs显示文摘In the development and regeneration of the nervous system, neurons face the complex task of establishing and/or repairing neuronal connections and contacts. The formation of these neuronal circuits is largely coordinated by tightly regulated temporal and spatial changes in mRNA translation, which enables incredibly precise control over protein expression and localization (Jung and Holt, 2011). Local mRNA translation in specific cellular compartments appears to play a role in many processes that are important to nervous system development and regeneration, including: cell survival, migration, growth cone guidance, and synaptogenesis (Jung and Holt, 2011). | Sarah E.Walker Gaynor E.Spencer Robert L.Carlone | 2019 | Neural Regeneration Research2019，14，10： | 0 |
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