ORCID Profile
0000-0002-3664-8752
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.BONE.2013.01.015
Abstract: Tissue level structural and mechanical properties are important determinants of bone strength. As an in idual ages, microstructural changes occur in bone, e.g., trabeculae and cortex become thinner and porosity increases. However, it is not known how the elastic properties of bone change during aging. Bone tissue may lose its elasticity and become more brittle and prone to fractures as it ages. In the present study the age-dependent variation in the spatial distributions of microstructural and microelastic properties of the human femoral neck and shaft were evaluated by using acoustic microscopy. Although these properties may not be directly measured in vivo, there is a major interest to investigate their relationships with the linear elastic measurements obtained by diagnostic ultrasound at the most severe fracture sites, e.g., the femoral neck. However, before the validity of novel in vivo techniques can be established, it is essential to understand the age-dependent variation in tissue elastic properties and porosity at different skeletal sites. A total of 42 transverse cross-sectional bone s les were obtained from the femoral neck (Fn) and proximal femoral shaft (Ps) of 21 men (mean±SD age 47.1±17.8, range 17-82years). S les were quantitatively imaged using a scanning acoustic microscope (SAM) equipped with a 50MHz ultrasound transducer. Distributions of the elastic coefficient (c33) of cortical (Ct) and trabecular (Tr) tissues and microstructure of cortex (cortical thickness Ct.Th and porosity Ct.Po) were determined. Variations in c33 were observed with respect to tissue type (c33Tr c33(Ct.Fn)=35.3GPa>c33(Tr.Ps)=33.8GPa>c33(Tr.Fn)=31.9GPa), and cadaver age (R(2)=0.28-0.46, p<0.05). Regional variations in porosity were found in the neck (superior 13.1% inferior 6.1% anterior 10.1% posterior 8.6%) and in the shaft (medial 9.5% lateral 7.7% anterior 8.6% posterior 12.0%). In conclusion, significant variations in elastic coefficients were detected between femoral neck and shaft as well as between the quadrants of the cross-sections of neck and shaft. Moreover, an age-related increase in cortical porosity and a stiffening of the bone tissue were observed. These findings may explain in part the increase in susceptibility to suffer low energy fractures during aging and highlight the potential of ultrasound in clinical osteoporosis diagnostics.
Publisher: MDPI AG
Date: 08-04-2021
Abstract: Mucopolysaccharidosis IIIA (MPS IIIA) is a lysosomal storage disease with significant neurological and skeletal pathologies. Respiratory dysfunction is a secondary pathology contributing to mortality in MPS IIIA patients. Pulmonary surfactant is crucial to optimal lung function and has not been investigated in MPS IIIA. We measured heparan sulphate (HS), lipids and surfactant proteins (SP) in pulmonary tissue and bronchoalveolar lavage fluid (BALF), and surfactant activity in healthy and diseased mice (20 weeks of age). Heparan sulphate, ganglioside GM3 and bis(monoacylglycero)phosphate (BMP) were increased in MPS IIIA lung tissue. There was an increase in HS and a decrease in BMP and cholesteryl esters (CE) in MPS IIIA BALF. Phospholipid composition remained unchanged, but BALF total phospholipids were reduced (49.70%) in MPS IIIA. There was a reduction in SP-A, -C and -D mRNA, SP-D protein in tissue and SP-A, -C and -D protein in BALF of MPS IIIA mice. Captive bubble surfactometry showed an increase in minimum and maximum surface tension and percent surface area compression, as well as a higher compressibility and hysteresis in MPS IIIA surfactant upon dynamic cycling. Collectively these biochemical and biophysical changes in alveolar surfactant are likely to be detrimental to lung function in MPS IIIA.
Publisher: Oxford University Press (OUP)
Date: 15-05-2020
DOI: 10.1093/NDT/GFZ076
Abstract: There is widespread recognition that research will be more impactful if it arises from partnerships between patients and researchers, but evidence on best practice for achieving this remains limited. We convened workshops in three Australian cities involving 105 patients/caregivers and 43 clinicians/researchers. In facilitated breakout groups, participants discussed principles and strategies for effective patient involvement in chronic kidney disease research. Transcripts were analysed thematically Five major themes emerged. ‘Respecting consumer expertise and commitment’ involved valuing unique and erse experiential knowledge, clarifying expectations and responsibilities, equipping for meaningful involvement and keeping patients ‘in the loop’. ‘Attuning to in idual context’ required a preference-based multipronged approach to engagement, reducing the burden of involvement and being sensitive to the patient journey. ‘Harnessing existing relationships and infrastructure’ meant partnering with trusted clinicians, increasing research exposure in clinical settings, mentoring patient to patient and extending reach through established networks. ‘Developing a coordinated approach’ enabled power in the collective and united voice, a systematic approach for equitable inclusion and streamlining access to opportunities and trustworthy information. ‘Fostering a patient-centred culture’ encompassed building a community, facilitating knowledge exchange and translation, empowering health ownership, providing an opportunity to give back and cultivating trust through transparency. Partnering with patients in research requires respect and recognition of their unique, erse and complementary experiential expertise. Establishing a supportive, respectful research culture, responding to their in idual context, coordinating existing infrastructure and centralizing the flow of information may facilitate patient involvement as active partners in research.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-0006
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.ULTRASMEDBIO.2009.10.008
Abstract: Quantitative ultrasound (QUS) measurements are used in the diagnostics of osteoporosis. However, the variation in the thickness and composition of the overlying soft tissue causes significant errors to the bone QUS parameters and diminishes the reliability of the technique in vivo. Recently, the dual frequency ultrasound (DFUS) technique was introduced to minimize the errors related to soft tissue effects. In this study, the significance of soft tissue induced errors and their elimination with the DFUS technique were simulated using the finite difference time domain technique. Furthermore, we investigated the potential of the DFUS corrected integrated reflection coefficient (IRC) of bone to detect changes in the cortical bone density. The effects of alterations in the thickness of fat and lean tissue layers and the inclination between the soft-tissues and between the soft tissue-bone layers were simulated. When the angle of the soft tissue interface was zero, i.e., perpendicular to the incident ultrasound beam, the DFUS-calculated soft tissue composition correlated highly linearly with the true soft tissue composition. The inclination between the soft tissue-bone layers was found to be critical. Even a 2-degree inclination between the soft tissue and the bone surface induced an almost 18% relative error in the corrected IRC. Increasing the inclination between the soft tissue layers increased the error in the DFUS-calculated lean and fat tissue thickness. This error was especially significant at inclination angles greater than 20 degrees. The significant soft tissue induced errors in IRC values (>300 %) could be effectively minimized (<10%) by means of the DFUS correction. Importantly, after the DFUS correction, physiologically relevant variation in the cortical bone density could be detected (p<0.05).
No related grants have been discovered for Tamara Paget.