What is it that defines an animal? The definition provided here, made on the basis of developmental biology, suggests methods for resolving phylogenetic problems.
Fertilization-induced cytoplasmic flows are a conserved feature of eggs in many species. However, until now the importance of cytoplasmic flows for the development of mammalian embryos has been unknown. Here, by combining a rapid imaging of the freshly fertilized mouse egg with advanced image analysis based on particle image velocimetry, we show that fertilization induces rhythmical cytoplasmic movements that coincide with pulsations of the protrusion forming above the sperm head. We find that these movements are caused by contractions of the actomyosin cytoskeleton triggered by Ca2+ oscillations induced by fertilization. Most importantly, the relationship between the movements and the events of egg activation makes it possible to use the movements alone to predict developmental potential of the zygote. In conclusion, this method offers, thus far, the earliest and fastest, non-invasive way to predict the viability of eggs fertilized in vitro and therefore can potentially improve greatly the prospects for IVF treatment.
The results have significant implications for quality improvement in the NHS. The finding that some NHS providers consistently perform better than others suggests that there are system-wide determinants of patient experience and the potential for learning from innovators. However, there is room for improvement overall. Given the large samples of these surveys, the messages could also have relevance for healthcare systems elsewhere.
The A&E department questionnaire is a valid and reliable questionnaire to assess patients' experiences with the A&E. The discriminative power of six summary scores offers a reliable comparison of healthcare performance between A&Es to increase patient centredness and quality of care.
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