Creating a Lizard Brain Atlas

Until recently, reptilian evolutionary studies lacked an important resource – a lizard brain atlas. As the subject of numerous ecological and behavioural studies, the Australian tawny dragon (Agamidae: Ctenophorus decresii) was an ideal candidate for creating a high-resolution MRI atlas of a representative scaled reptile (squamata). Such data is not only a resource for studies of the genus but also informs environmental decision making through an improved understanding of animal adaptation and evolution.

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MRI investigations of placental structure and function

Preeclampsia is a medical condition affecting up to 3% of pregnant women in Australia. Characterised by high blood pressure and protein in the urine, it is a leading cause of morbidity and mortality in both mothers and infants. Furthermore, preeclampsia has been linked to long-term health consequences for both mother and child.

3-D reconstructions of the placenta from MRI images. (left) Foetal surface view of the placenta. (middle) Maternal surface view of the placenta with an overlay showing maternal vasculature. (right) Side view showing maternal vasculature alone

Hampering early diagnosis, prevention, and treatment efforts is a lack of understanding of preeclampsia pathophysiology.  Currently, the cause of this condition is unknown. Prof Annemarie Hennessy and a team of researchers at Western Sydney University are utilising the WSU NIF Node, in collaboration with NIF Fellow Dr Timothy Stait-Gardner, to learn more about this serious condition.

In this project, high-resolution magnetic resonance imaging is being used to examine placental changes in vivo in mouse models of preeclampsia. In addition to the in vivo studies, high-resolution scans of fixed mouse placentas, normal and abnormal, have been used to create a placental atlas. The creation of a placental atlas and a number of publications have provided important information on mouse models of preeclampsia, including its characterisation and how to differentiate between different models of preeclampsia from T2 maps of the mouse placentas. These works have provided some of the basis for investigations of new treatments of preeclampsia.

Publications:

This story was contributed by the Western Sydney University NIF Node. For further information, please contact Dr Timothy Stait-Gardner.

Grape split imaging to examine physical changes before and after splitting using diffusion magnetic resonance

Berry split is a condition in which the grape epidermis splits which often occurs during periods of high rainfall and is a significant cause of grape crop loss. In damp conditions there is increased uptake of water via osmosis and decreased water loss from transpiration. The pre-dawn turgor pressure of table grape cultivars lies in the vicinity of 5-38 kPa but prior to berry split can be as high as 1.5-3.7 MPa.
In order to examine and characterise the immediate effect of fruit split on grape, National Wine & Grape Industry and Western Sydney University node of National Imaging Facility have been collaborating on an ongoing project, which investigates the physical changes within the grape berry both before and after splitting using diffusion magnetic resonance imaging. Thirty-six table grapes of the Thompson Seedless variety were involved in the study and assigned to three groups: a control group (12 berries), a group in which they were wrapped in damp tissue (12 berries), and a total immersion group (12 berries). Five axial images (including diffusion tensor images) spaced evenly apart along the length of each berry were acquired simultaneously every hour to create a time-course study of each grape.
For each grape that split within the MRI during the study it was observed that there was an immediate change in the diffusion coefficient in the region of the wound. This region increased in volume over the course of the subsequent scans and correlated with regions of non-vital cells (as determined by fluorescence microscopy). It was determined from the study that grape berries left exposed to standing water after splitting exhibit greater cell death within the vicinity of the split. Therefore, the surface of split berries should be kept dry if possible to reduce further damage.

 

Collaborators

Nanoscale Organisation and Dynamics Group, University of Western Sydney
School of Medicine, University of Western Sydney
National Wine & Grape Industry Centre
NSW Department of Primary Industries

Sources

Dean, R.J., Bobek, G., Stait-Gardner, T., Clarke, S.J., Rogiers, S.Y. and Price, W.S. (2015), Time-course study of grape berry split using diffusion magnetic resonance imaging. Aust. J. Grape Wine R. doi: 10.1111/ajgw.12184
Dean R.J., Stait-Gardner, T., Clarke, S.J., Rogiers, S.Y., Bobek, G. and Price, W.S. (2014) Use of diffusion magnetic resonance imaging to correlate the developmental changes in grape berry tissue structure with water diffusion patterns. Plant methods 10(1):35

 

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