No abstract

Large White (LW) and Meishan (MS) gilts were killed on Days 8, 10, 11, 12, 14 and 30 of gestation. Mean diameters (mm) for MS and LW conceptuses, respectively, were: Day 8, 0.45 and 0.69; Day 10, 2.7 and 1.9; Day 11, 5.3 and 2.7, with the differences among days being affected by breed (P less than 0.01). Variation in diameter among conceptuses from LW gilts was greater (P less than 0.01) than that for MS gilts on Days 8-11, respectively: Day 8, 20 and 46%; Day 10, 29 and 38%; and Day 11, 22 and 44%. Conceptuses had elongated in 3 of 5 MS and 1 of 4 LW gilts on Day 11, 6 and 6 MS and 2 of 4 LW gilts on Day 12 and all gilts of both breeds on Day 14. These results indicate that conceptuses of MS gilts develop more rapidly and more uniformly between Days 8 and 14 of gestation. Overall, embryonic survival for Days 8-12 for gilts not having elongated conceptuses was 90.2% for MS and 73.2% for LW gilts (P less than 0.01). On Day 30 of gestation, embryonic survival was also higher (P less than 0.01) for MS (89%) than LW (55%) gilts. However, embryonic weight, crown-rump length, placental length, allantoic fluid volume, amniotic fluid volume, as well as total glucose, fructose and protein in allantoic fluid were not affected by breed. Placental weight was greater (P less than 0.01) for LW gilts. Uterine development at Day 30 of gestation, based on total length and weight of uterine horns, width of uterine horns, total endometrial surface area and total endometrial weight was greater (P less than 0.01) for LW gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

No abstract

No abstract

The aims of this study were to assess the effectiveness of roscovitine, a potent inhibitor of cell cyclin kinases, to prevent meiotic resumption in porcine oocytes, and to test the subsequent fertilisability and developmental competence of these oocytes. Roscovitine blocked porcine oocytes at the GV stage during 22-44 hr of culture. This effect was dose-dependent, and a concentration of 25 microM was sufficient to prevent meiotic resumption in 92+/-5% of the oocytes after 22 hr in the presence of EGF and FSH. Cumulus expansion was also inhibited under these conditions. The histone H1 kinase activity in oocytes was inhibited in a dose-dependent way, and maintained at a basal level with 25 microM of roscovitine. Synthesis of proteins of 29, 47 and 79 kDa, normally synthesized during maturation, was inhibited too. All these effects were fully reversible. However, the kinetics of maturation were accelerated after roscovitine removal, and the acceleration was more pronounced after 44 hr of inhibition than after 22 hr. Fertilization of oocytes blocked for 22 hr before a 44 hr maturation was decreased compared to control, but was not different from that of oocytes matured for 66 hr. The developmental competence was decreased for the oocytes cultured for 66 hr, including or not an inhibition period, but it was less reduced for oocytes maintained under inhibition for 22 hr. Roscovitine may thus protect oocytes against the aging mechanisms responsible for developmental competence loss, but not against loss of fertilisability. In conclusion, roscovitine provides a useful tool to study the morphological and biochemical basis of porcine oocyte terminal differentiation.

No abstract

No abstract

The transplantation of fetal porcine neurons is a potential therapeutic strategy for the treatment of human neurodegenerative disorders. A major obstacle to xenotransplantation, however, is the immune-mediated rejection that is resistant to conventional immunosuppression. To determine whether genetically modified donor pig neurons could be used to deliver immunosuppressive proteins locally in the brain, transgenic pigs were developed that express the human T cell inhibitory molecule hCTLA4-Ig under the control of the neuron-specific enolase promoter. Expression was found in various areas of the brain of transgenic pigs, including the mesencephalon, hippocampus and cortex. Neurons from 28-day old embryos secreted hCTLA4-Ig in vitro and this resulted in a 50% reduction of the proliferative response of human T lymphocytes in xenogenic proliferation assays. Transgenic embryonic neurons also secreted hCTLA4-Ig and had developed normally in vivo several weeks after transplantation into the striatum of immunosuppressed rats that were used here to study the engraftment in the absence of immunity. In conclusion, these data show that neurons from our transgenic pigs express hCTLA4-Ig in situ and support the use of this material in future pre-clinical trials in neuron xenotransplantation.