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Madakamutil LT Christen U Lena CJ Wang-Zhu Y Attinger A Sundarrajan M Ellmeier W von Herrath MG Jensen P Littman DR Cheroutre H 《Science (New York, N.Y.)》2004,304(5670):590-593
Memory T cells are long-lived antigen-experienced T cells that are generally accepted to be direct descendants of proliferating primary effector cells. However, the factors that permit selective survival of these T cells are not well established. We show that homodimeric alpha chains of the CD8 molecule (CD8alphaalpha) are transiently induced on a selected subset of CD8alphabeta+ T cells upon antigenic stimulation. These CD8alphaalpha molecules promote the survival and differentiation of activated lymphocytes into memory CD8 T cells. Thus, memory precursors can be identified among primary effector cells and are selected for survival and differentiation by CD8alphaalpha. 相似文献
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Lipid profiles of canine spermatozoa as revealed via matrix‐assisted laser desorption/ionization mass spectrometry
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LT Braga Jr. NRS Bravo KRA Belaz D Zampieri MN Eberlin VA Conforti 《Reproduction in domestic animals》2016,51(6):1055-1058
In this study, we investigated the ability of matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) to characterize the lipid contents of canine spermatozoa. For that, samples of pure semen were analysed. Indeed, quite comprehensive lipid coverage was observed, and the most abundant phospholipid ions detected were from four phosphatidylcholines, that is those of m/z 760.6; 782.6; 808.6; and 830.6 and one of m/z 725.6 from a sphingomyelin. In conclusion, MALDI‐MS was found to offer an easy, fast, accurate, and sensitive analytical method for lipid profiling in canine spermatozoa and could be used as a tool to select sires by assessing the relationship between sperm lipid profiles and variables such as age and breeding history as well as to study the effects of cryopreservation on lipid contents. 相似文献
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C Feltrin CA Cooper N Mohamad‐Fauzi VHV Rodrigues LH Aguiar S Gaudencio‐Neto LT Martins CEM Calderón AS Morais IS Carneiro TM Almeida ING Silva JL Rodrigues EA Maga JD Murray AB Libório LR Bertolini M Bertolini 《Reproduction in domestic animals》2014,49(4):648-656
The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona‐free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre‐treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona‐free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo‐ vs in vitro‐matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona‐free and zona‐intact goat cloned embryos. 相似文献
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Reproductive performance of immobilized cryopreserved bovine semen used for timed artificial insemination
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AH Alm‐Kristiansen G Dalen G Klinkenberg L Bekk LT Thorkildsen KE Waterhouse E Kommisrud 《Reproduction in domestic animals》2017,52(6):1019-1024
The SpermVital® technology comprises embedding of spermatozoa within an alginate gel to facilitate release of sperm cells over a prolonged period in utero after AI. The aim of this study was to examine whether the survival time of spermatozoa is extended when applying this immobilization technology in combination with cryopreservation. Sperm cell survival (acrosome and plasma membrane integrity) was studied in vitro for 48 hr at physiological temperature. One dose of SpermVital® (SV) semen was compared with single doses of Biladyl® (B) processed semen as well as double doses of B (B double). B double was obtained by adding a second B dose the following day, thereby mimicking double AI. Furthermore, reproductive performance applying single early timed AI (TAI) with SV following oestrus synchronization was studied in a field trial. Double insemination (TAI on two consecutive days) with B semen served as control. Number of acrosome‐intact live sperm cells decreased over time in vitro for all treatments (p < .05). There was no difference between SV sperm cell survival and B double after 24 hr (p > .05). However, after 48 hr, SV sperm cell survival was higher than B double (p < .05). Moreover, multivariate analysis showed that the outcome of single early TAI with SV was not significantly different from B double (p > .05). Likelihood of pregnancy and calving in the heifer group was higher than in the cow group (p < .05). These results imply that spermatozoa immobilized in alginate gel have prolonged survival. 相似文献
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