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Papers by Gary Cowin

Journal of Labelled Compounds and Radiopharmaceuticals, 2019

Frontiers in Physics, 2022

Efficacy of diagnostics and therapeutics for brain tumours can be modulated by vascular delivery ... more Efficacy of diagnostics and therapeutics for brain tumours can be modulated by vascular delivery and blood brain barrier permeability. Simultaneous dynamic gadolinium MR-PET enables independent assessment of vascular delivery and blood brain barrier integrity in a brain tumour animal model in the presence of a PET tracer.Dual echo dynamic gadolinium enhanced gradient echo imaging allows simultaneous calculation of T2* and T1 images from the TE image pairs. Relaxivity values then enabled determination of independent T2*- and T1-derived gadolinium concentrations simultaneously with measurement of [18F]DPA-714 neuroinflammation radiotracer delivery.Separate T2*- and T1-derived gadolinium concentrations curves were derived in a selection of tumours and normal tissue, reflecting vascular delivery and tissue uptake. Changes in the PET activity curves were seen in tumours and normal tissue, reflecting changes in the MR derived dynamic curves. The dramatic changes in the MR-derived vascular...

Combined supplementary material

A prospective study of nomogram-based adaptation of prostate radiotherapy target volumes

Magnetic resonance microimaging was used to measure dif-fusion decay over an extended b-factor ra... more Magnetic resonance microimaging was used to measure dif-fusion decay over an extended b-factor range in a formalin-fixed normal prostate sample and a Gleason pattern 314 can-cer tissue sample. The coefficients of biexponential fits to dif-fusion decay data from 1600 voxels of dimension 160 3 160 3 160 mm3 in each sample were correlated with underlying epithelial and stromal compartment partial volumes estimated from high-resolution apparent diffusion coefficient (ADC) data (40 3 40 3 40 mm3 voxels) from the same tissue. In the nor-mal tissue sample, the signal fractions of the low and high ADC components of the biexponential fits correlated linearly with partial volumes of epithelial tissue (R2 5 0.6) and stromal tissue (R2 5 0.5), respectively. Similar but weaker correlations were observed in the cancer sample. Epithelium-containing high spatial resolution voxels appeared to be composed of

Introduction:Echo Planar Diffusion weighted imaging is the current method of choice for utilising... more Introduction:Echo Planar Diffusion weighted imaging is the current method of choice for utilising the diffusion properties of water to localise cancer tumours. While it has had success in distinguishing tumours from tissue it is highly sensitive to chemical shift, magnetic susceptibility and phase error, which produce artefacts in the ADC map images. We propose to use HASTE, which is less affected by these artefacts, for prostate cancer tumour detection. In this study ADC values were investigated for tumours and healthy tissue in both sequences.For accurate detection of tumours and possible monitoring of disease,the tumour ADC value should be distinctly different, compared to healthy tissue

ABSTRACT This article describes the utility of MRI as a non invasive research tool for studying t... more ABSTRACT This article describes the utility of MRI as a non invasive research tool for studying the bruising (and other internal quality features) of avocado fruit.

Quantitative assessment of the central nervous system enables ecomorphologists and sensory neurob... more Quantitative assessment of the central nervous system enables ecomorphologists and sensory neurobiologists to correlate the morphology and relative size of sensory brain regions with behavior and ecology. Assessment of the contribution of each sensory brain region to total brain volume has traditionally been used to identify the relative importance of a specific sensory modality with respect to each species’ ecological niche. Direct observations of behavior have confirmed such an approach. However, as new species are found in relatively inaccessible environments e.g. deep-sea and polar oceans, analysis of their 'natural' behaviors is exceedingly difficult, where the gross assessments of the size of the sensory brain regions are the only indicator of behavior. Therefore, the precision of this gross assessment is even more vital. In order to examine the accuracy of traditional methodologies (brain size determined by either extrapolation of volume using the ellipsoid model and/...

Wang, Deming, Chalk, Jonathan, deZubicaray, Greg, Rose, Stephen, Strudwick, Mark, Durbridge, Gail... more Wang, Deming, Chalk, Jonathan, deZubicaray, Greg, Rose, Stephen, Strudwick, Mark, Durbridge, Gail, Cowin, Gary, McMahon, Katie, McKinnon, David, Galloway, Graham and Doddrell, David (2006). Brain atrophy progression measured with structural in normal ...

Overlap syndrome is used to describe variant forms of autoimmune hepatitis (AIH) which present wi... more Overlap syndrome is used to describe variant forms of autoimmune hepatitis (AIH) which present with characteristics of AIH and primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC). Patients with overlap syndromes present with both hepatitic and cholestatic serum liver tests and have histological features of AIH and PBC or PSC. AIH-PBC is the most common form of overlap syndrome, affecting almost 10 of adults with AIH or PBC. Overlap syndromes show a progressive course without treatment, and therapy is empiric. Ursodeoxycholic acid is usuallycombined with immunosuppressive therapy but end-stage disease requires liver transplantation. We report a case of AIH-PBC overlap syndrome presenting with jaundice.

Regional Anesthesia & Pain Medicine, 2021

Background and objectivesThe ‘loss of resistance’ technique is used to determine entry into the e... more Background and objectivesThe ‘loss of resistance’ technique is used to determine entry into the epidural space, often by a midline needle in the interspinous ligament before the ligamentum flavum. Anatomical explanations for loss of resistance without entry into the epidural space are lacking. This investigation aimed to improve morphometric characterization of the lumbar interspinous ligament by observation and measurement at dissection and from MRI.MethodsMeasurements were made on 14 embalmed donor lumbar spines (T12 to S1) imaged with MRI and then dissected along a tilted axial plane aligned with the lumbar interspace.ResultsIn 73 interspaces, median (IQR) lumbar interspinous plus supraspinous ligament length was 29.7 mm (25.5–33.4). Posterior width was 9.2 mm (7.7, 11.9), with narrowing in the middle (4.5 mm (3.0, 6.8)) and an anterior width of 7.3 mm (5.7, 9.8).Fat-filled gaps were present within 55 (75%). Of 51 anterior gaps, 49 (67%) were related to the ligamenta flava juncti...

Materials Science and Engineering: C, 2021

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflamm... more In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl4-treated C57BL/6 mice, demonstrated by a shortened T2⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl4 treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl4-treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases.

Scientific Reports, 2021

While the dire cardiometabolic consequences of the hypercaloric modern ‘Western’ diet are well kn... more While the dire cardiometabolic consequences of the hypercaloric modern ‘Western’ diet are well known, there is not much information on the health impact of a high sucrose diet not inducing weight gain. Here, we tested the hypothesis that rats reared with intermittent binge access to sucrose in addition to normal chow would develop an inflammatory response in brain. To test this hypothesis, we undertook serial PET/MRI scans with the TSPO ligand [18F]DPA714 in a group of (n=9) rats at baseline and again after voluntarily consuming 5% sucrose solution three days a week for three months. Compared to a control group fed with normal chow (n=9), the sucrose rats indeed showed widespread increases in the availability of cerebral binding sites for the microglial marker, despite normal weight gain compared to the control diet group. Subsequent immunofluorescence staining of the brains confirmed the PET findings, showing a widespread 20% increase in the abundance of IBA-1-positive microglia wi...

European Spine Journal, 2020

Purpose Injury to the cervical spinal cord has been suggested as a mechanism that may underpin ch... more Purpose Injury to the cervical spinal cord has been suggested as a mechanism that may underpin chronic whiplash-associated disorder (WAD). This study aimed to assess metabolite concentrations indicative of neuronal injury or pathology in the cervical cord in people with chronic WAD. Methods Forty-one people with chronic WAD (mean [SD] age 39.6 [11.0] years, 25 females) and 14 healthy controls (39.2 [12.6] years, 9 females) underwent cervical spinal cord magnetic resonance spectroscopy to measure the metabolites N -acetylaspartate (NAA), creatine (Cr) and choline (Cho). Participants with WAD completed clinical questionnaires on pain intensity (Visual Analogue Scale), disability (Neck Disability Index) and psychological factors (Pain Catastrophising Scale, Post-traumatic Diagnostic Scale), and underwent cervical range of motion assessment and pain threshold testing to cold and pressure stimuli. Data were analysed using hypothesis testing and Spearman correlations ( p < 0.05). Results There were no differences between the WAD and control groups for NAA/Cr (median [IQR] WAD 1.73 [1.38, 1.97], controls 2.09 [1.28, 2.89], p = 0.37), NAA/Cho (WAD 1.50 [1.18, 2.01], controls 1.57 [1.26, 1.93], p = 0.91) or Cr/Cho (WAD 0.84 [0.64, 1.17], controls 0.76 [0.60, 0.91], p = 0.33). There were no significant correlations between NAA/Cr, NAA/Cho or Cr/Cho and any clinical variable ( p ≥ 0.06). Conclusions Findings are consistent with major metabolic changes not being present in chronic WAD.

Molecular Neurobiology, 2020

American Journal of Physiology-Renal Physiology, 1999

Renal osmolyte concentrations are reduced during reflow following ischemia. Osmolyte decreases ma... more Renal osmolyte concentrations are reduced during reflow following ischemia. Osmolyte decreases may follow oxygen depletion or loss of extracellular osmolality in the medulla. Image-guided volume-localized magnetic resonance (MR) microspectroscopy was used to monitor regional osmolytes during hyposmotic shock and hypoxia in the intact rat kidney. Alternate spectra were acquired from 24-μl voxels in cortex and medulla of the isolated perfused kidney. There was a progressive decrease in the combined betaine-glycerophosphorylcholine (GPC) peak intensity of 21% in cortex and 35% in medulla of normoxic kidneys between 60 and 160 min after commencing perfusion. Hypoxia had no significant effect on the betaine-GPC peak intensity in cortex or medulla, despite a dramatic reduction in tubular sodium, potassium, and water reabsorption. The results suggest that cortical and medullary intracellular osmolyte concentrations depend on osmotically regulated channels that are insensitive to oxygen and...