This DOI contains a micro CT stack of the frozen head of a King penguin (<i>Aptenodytes pat... more This DOI contains a micro CT stack of the frozen head of a King penguin (<i>Aptenodytes patagonicus</i>), originally from South Georgia. <br> <br>
OBJECTIVE To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging... more OBJECTIVE To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging (3-D MRI) with gadolinium contrast agent enhancement in monitoring soft tissue and hard tissue changes during the course of antigen-induced arthritis in rabbits, comparing the images with the final histologic outcome. METHODS Arthritis was induced by intraarticular injection of methylated bovine serum albumin into rabbits that had been presensitized to the same antigen. MRI was carried out before and on predetermined days after the onset of inflammatory arthritis, up to day 60. At each time point, 3-D gradient-echo images were acquired. At the end of the study, the knee joints were processed for histologic study. RESULTS Time-related inflammatory changes, such as soft tissue swelling, were seen initially, followed by a reduction in the acute swelling and a progression to hard tissue damage at later time points. The final 3-D data sets were then used to compare MR images with the histologic sections. The knee joints were sectioned in the sagittal, coronal, or transverse direction. Comparison of final images and histologic features at day 60 enabled a more complete interpretation of the MR images, allowing direct correlation of joint damage observed using the MRI technique with that seen in the final histologic analysis. CONCLUSION Qualitative information derived from MR images correlated extremely well with histologic findings. These results indicate the great potential of MRI for noninvasive investigation of drug effects in this model of arthritis.
Traumatic brain injury (TBI) is a leading cause of death and disability. The way mechanical impac... more Traumatic brain injury (TBI) is a leading cause of death and disability. The way mechanical impact is transferred to the brain has been shown to be a major determinant for structural damage and subsequent pathological sequalae. Although finite element (FE) models have been used extensively in the investigation of various aspects of TBI and have been instrumental in characterising a TBI injury threshold and the pattern of diffuse axonal injuries, subject-specific analysis has been difficult to perform due to the complexity of brain structures and its material properties. We have developed an efficient computational pipeline that can generate subject-specific FE models of the brain made up of conforming hexahedral elements directly from advanced MRI scans. This pipeline was applied and validated in our sheep model of TBI. Our FE model of the sheep brain accurately predicted the damage pattern seen on post-impact MRI scans. Furthermore, our model also showed a complex time-varying stra...
Part of collection that contains images obtained during dissection of the heads of little penguin... more Part of collection that contains images obtained during dissection of the heads of little penguins (Eudyptula minor) from Auckland, king penguins (Aptenodytes patagonicus) and gentoo penguins (Pygoscelis papua), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
DPP-4 inhibitors are anti-diabetic drugs that enhance renal Na+ and fluid excretion. We tested wh... more DPP-4 inhibitors are anti-diabetic drugs that enhance renal Na+ and fluid excretion. We tested whether the DPP-4 inhibitor alogliptin (ALG) ameliorates PPARγ agonists pioglitazone (PGZ)-induced flu...
Arteriosclerosis, Thrombosis, and Vascular Biology, 2015
Introduction: Cerebral microhemorrhages (CMH) are tiny deposits of blood degradation products in ... more Introduction: Cerebral microhemorrhages (CMH) are tiny deposits of blood degradation products in the brain and are the pathological substrate of cerebral microbleeds (MB). The existing animal models of MB are either β-amyloid-, anti-amyloid antibody-, or hypertension-induced; however, MB may develop independent of hypertension or amyloid deposition. In fact, MB are associated with normal aging, sepsis and neurodegenerative conditions. One common factor among the above pathologies is inflammation, and recent studies show a link between systemic inflammation and MB. Hence, we hypothesize that systemic inflammation (induced by lipopolysaccharide; LPS) will result in MB development, and an inflammation-induced animal model will be appropriate to study MB. In the current study we used two different dosing regimens for LPS and observed rapid and robust development of CMH and MB. Methods: Adult C57BL/6 mice were injected with LPS (1mg/kg or 3mg/kg, i.p.) or saline at 0, 6, and 24h. At 2 or...
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive pe... more Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2s at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2s were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not ...
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive pe... more Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2s at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2s were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not ...
This DOI contains a micro CT stack of the frozen head of a King penguin (<i>Aptenodytes pat... more This DOI contains a micro CT stack of the frozen head of a King penguin (<i>Aptenodytes patagonicus</i>), originally from South Georgia. <br> <br>
OBJECTIVE To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging... more OBJECTIVE To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging (3-D MRI) with gadolinium contrast agent enhancement in monitoring soft tissue and hard tissue changes during the course of antigen-induced arthritis in rabbits, comparing the images with the final histologic outcome. METHODS Arthritis was induced by intraarticular injection of methylated bovine serum albumin into rabbits that had been presensitized to the same antigen. MRI was carried out before and on predetermined days after the onset of inflammatory arthritis, up to day 60. At each time point, 3-D gradient-echo images were acquired. At the end of the study, the knee joints were processed for histologic study. RESULTS Time-related inflammatory changes, such as soft tissue swelling, were seen initially, followed by a reduction in the acute swelling and a progression to hard tissue damage at later time points. The final 3-D data sets were then used to compare MR images with the histologic sections. The knee joints were sectioned in the sagittal, coronal, or transverse direction. Comparison of final images and histologic features at day 60 enabled a more complete interpretation of the MR images, allowing direct correlation of joint damage observed using the MRI technique with that seen in the final histologic analysis. CONCLUSION Qualitative information derived from MR images correlated extremely well with histologic findings. These results indicate the great potential of MRI for noninvasive investigation of drug effects in this model of arthritis.
Traumatic brain injury (TBI) is a leading cause of death and disability. The way mechanical impac... more Traumatic brain injury (TBI) is a leading cause of death and disability. The way mechanical impact is transferred to the brain has been shown to be a major determinant for structural damage and subsequent pathological sequalae. Although finite element (FE) models have been used extensively in the investigation of various aspects of TBI and have been instrumental in characterising a TBI injury threshold and the pattern of diffuse axonal injuries, subject-specific analysis has been difficult to perform due to the complexity of brain structures and its material properties. We have developed an efficient computational pipeline that can generate subject-specific FE models of the brain made up of conforming hexahedral elements directly from advanced MRI scans. This pipeline was applied and validated in our sheep model of TBI. Our FE model of the sheep brain accurately predicted the damage pattern seen on post-impact MRI scans. Furthermore, our model also showed a complex time-varying stra...
Part of collection that contains images obtained during dissection of the heads of little penguin... more Part of collection that contains images obtained during dissection of the heads of little penguins (Eudyptula minor) from Auckland, king penguins (Aptenodytes patagonicus) and gentoo penguins (Pygoscelis papua), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
Part of collection that contains images obtained during scanning and dissection of the heads of l... more Part of collection that contains images obtained during scanning and dissection of the heads of little penguins (<i>Eudyptula minor</i>) from Auckland, king penguins (<i>Aptenodytes patagonicus</i>) and gentoo penguins (<i>Pygoscelis papua</i>), the latter two descended from penguins from South Georgia. It also contains a video of the eye of a little penguin from Auckland viewed under both bright (photopic) and dim (mesopic) conditions, while undergoing general anaesthesia, to show the movement of the pupil as well as renders made from these images.
DPP-4 inhibitors are anti-diabetic drugs that enhance renal Na+ and fluid excretion. We tested wh... more DPP-4 inhibitors are anti-diabetic drugs that enhance renal Na+ and fluid excretion. We tested whether the DPP-4 inhibitor alogliptin (ALG) ameliorates PPARγ agonists pioglitazone (PGZ)-induced flu...
Arteriosclerosis, Thrombosis, and Vascular Biology, 2015
Introduction: Cerebral microhemorrhages (CMH) are tiny deposits of blood degradation products in ... more Introduction: Cerebral microhemorrhages (CMH) are tiny deposits of blood degradation products in the brain and are the pathological substrate of cerebral microbleeds (MB). The existing animal models of MB are either β-amyloid-, anti-amyloid antibody-, or hypertension-induced; however, MB may develop independent of hypertension or amyloid deposition. In fact, MB are associated with normal aging, sepsis and neurodegenerative conditions. One common factor among the above pathologies is inflammation, and recent studies show a link between systemic inflammation and MB. Hence, we hypothesize that systemic inflammation (induced by lipopolysaccharide; LPS) will result in MB development, and an inflammation-induced animal model will be appropriate to study MB. In the current study we used two different dosing regimens for LPS and observed rapid and robust development of CMH and MB. Methods: Adult C57BL/6 mice were injected with LPS (1mg/kg or 3mg/kg, i.p.) or saline at 0, 6, and 24h. At 2 or...
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive pe... more Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2s at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2s were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not ...
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive pe... more Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2s at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2s were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not ...
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Papers by Miriam Scadeng