No abstract

In vivo-derived bovine embryos are of higher quality than those derived in vitro. Many of the differences in quality can be related to culture environment-induced changes in mRNA abundance. The aim of this study was to identify a range of mRNA transcripts that are differentially expressed between bovine blastocysts derived from in vitro versus in vivo culture. Microarray (BOTL5) comparison between in vivo-and in vitro-cultured bovine blastocysts identified 384 genes and expressed sequence tags (ESTs) that were differentially expressed; 85% of these were down-regulated in in vitro cultured blastocysts, showing a much reduced overall level of mRNA expression in in vitro-compared with in vivo-cultured blastocysts. Relative expression of 16 out of 23 (70%) differentially expressed genes (according to P value) were verified in new pools of in vivo-and in vitrocultured blastocysts, using quantitative real-time PCR. Most (10 out of 16) are involved in transcription and translation events, suggesting that the reason why in vitro-derived embryos are of inferior quality compared with in vivo-derived embryos is due to a deficiency of the machinery associated with transcription and translation.

No abstract

Term and near-term infants account for a significant proportion of neonatal admissions and deserve regular audit. Many admissions are potentially avoidable. Survival for infants weighing 2,500 grams or greater is excellent. Only one normally formed infant died following admission during the study period. The number of "social" admissions of "well" infants highlighted by this study reflects poorly on the services available for well infant whose mothers are unable to care for them for whatever reason. We recommend regular audit of these infants in order to ensure efficient use of neonatal resources and to ensure optimum levels of neonatal intensive care.

The post-fertilization embryo culture environment can have a dramatic effect on the pattern of gene expression in the embryo and it is widely acknowledged that bovine embryos derived from in vitro culture are of inferior quality to those derived in vivo. The objective of this study was to examine temporal variation in the mRNA abundance of several transcription and translation factors known to differ between blastocysts produced following culture in vitro and in vivo. Embryos were recovered from two in vitro culture systems SOF1 or SOF2 at five developmental stages: 2- to 4-cell, 8-cell, 16-cell, morula, and blastocyst. In vivo embryos were produced from superovulated and artificially inseminated heifers and recovered at approximately 40 hr or 3, 4, 5, and 7 days postinsemination. Blastocysts were also produced following in vitro maturation, in vitro fertilization and culture in the ewe oviduct. Analysis of relative transcript abundance for FOXO3A, EEF1G, HMG2, and REA was performed using quantitative real-time PCR. Irrespective of culture environment each transcript followed, approximately the same general pattern of expression where relative abundance decreased dramatically from the 2- to 4-cell stage to 8-cell stage and increased from the morula to blastocyst stage (P < 0.05). Transcripts for GNBL2 were not observed between the 2- and 16-cell stage of development. Relatively high expression at the 2- to 4-cell indicated that these transcripts are most likely of maternal origin produced in the oocyte during growth and final maturation. A culture-induced change in mRNA abundance of transcription and translation factors was evident in embryos that were produced not only between in vivo and in vitro culture environments but also between different in vitro culture systems.