Rhythmic actomyosin-driven contractions induced by sperm entry predict mammalian embryo viability.

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 Ca(2+) 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

Evaluating the accuracy of preoperative imaging for diagnosing rotator cuff tears in a regional centre

To review the diagnostic performance of ultrasonography (US) and magnetic resonance imaging (MRI) for the detection of rotator-cuff tears, we performed a retrospective audit of patients who underwent shoulder arthroscopy at Hinchingbrooke hospital. The diagnostic accuracies of US for full and partial-thickness tears were 82% and 28% respectively. Those of MRI were 82% and 81% respectively. These were lower than expected from the literature. This discrepancy is likely to be the consequence of over-diagnosis in imaging and under-diagnosis at arthroscopy