The models resulting from such synthesis have revealed many novel insights into heart morphogenesis and, by extrapolation to humans, have shed light on the likely origins of several cardiac malformations. Generating accurate 3D models of complex structures such as the embryonic heart is an age-old problem, initially addressed over a century ago using camera lucida techniques with microtome sections as the basis for wax models. Despite the many advances in imaging technologies including 3D imaging modalities that have transformed medical diagnosis, adapting these to analyse in the

millimetre range necessary for embryos has proved challenging. As yet, neither magnetic resonance imaging nor the various tomographic methods Trametinib concentration (such as OPT and CT) can provide the resolution required to accurately model the changing morphology of the mouse heart over the course of embryonic development. The modern counterpart to the plate modelling of such nineteenth century pioneers as Born, His and Ziegler [1, 2 and 3] remains remarkably similar: computer-based 3D rendering using realigned images of histological tissue sections. Paradoxically, Idelalisib datasheet although images of histological sections are unmatched in the extraordinary detail of tissue and cellular architecture they can reveal, much

of this is lost from the 3D models produced by realigning sequential section images. This is a consequence of the variable and unpredictable distortions produced by tissue sectioning and staining and attempts to overcome this through choice of embedding medium, the inclusion of fiduciary markers or by computation have had only limited success [4, 5, 6, 7, 8, 9, 10, 11•, 12, 13, 14, 15, 16 and 17]. Episcopic 3D imaging methods provide a solution to this problem, replacing individual section

images with images of the embedded tissue block face [18•, 19•, 20, 21, 22, 23 and 24]. High-resolution episcopic microscopy (HREM) has proved the most effective of these, using the simple expedient of fluorescent dyes in the plastic embedding medium to obtain very detailed greyscale images from Methisazone a wide range of biological tissues and optical magnifications [25••]. For this reason it is particularly well suited to provide accurate data sets with which to explore the changing morphology of the developing heart (Figure 1a). Automation of a relatively rapid image capture cycle and the ability to choose inter-image distances as little as 1 μm with HREM equipment have several important benefits. Firstly, it is practical to analyse large numbers of samples. This is particularly helpful for analysing subtle or rapid developmental changes that make analysis of cardiac morphogenesis so challenging.