214 resultados para Collective cell migration


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Objective: This study documents the mental health status of people from Burmese refugee backgrounds, recently arrived in Australia; then examines the contributions of gender, premigration and postmigration factors in predicting mental health. Method: Structured interviews, including a demographic questionnaire, the Harvard Trauma Questionnaire, Postmigration Living Difficulties Checklist and Hopkins Symptom Checklist assessed premigration trauma, postmigration living difficulties, depression, anxiety, somatisation and traumatisation symptoms in a sample of 70 adults across five Burmese ethnic groups. Results: Substantial proportions of participants reported psychological distress in symptomatic ranges including: posttraumatic stress disorder (9%); anxiety (20%), and; depression (36%), as well as significant symptoms of somatisation (37%). Participants reported multiple and severe premigration traumas. Postmigration living difficulties of greatest concern included communication problems and worry about family not in Australia. Gender did not predict mental health. Level of exposure to traumatic events and postmigration living difficulties each made unique and relatively equal contributions to traumatisation symptoms. Postmigration living difficulties made unique contributions to depression, anxiety and somatisation symptoms. Conclusions: While exposure to traumatic events impacted on participants’ mental wellbeing, postmigration living difficulties had greater salience in predicting mental health outcomes of people from Burmese refugee backgrounds. Reported rates of posttraumatic stress disorder symptoms were consistent with a large review of adults across seven western countries. High levels of somatisation pointed to a nuanced expression of distress. Findings have implications for service provision in terms of implementing appropriate interventions to effectively meet the needs of this newly arrived group in Australia.

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Cell based therapies for bone regeneration are an exciting emerging technology, but the availability of osteogenic cells is limited and an ideal cell source has not been identified. Amniotic fluid-derived stem (AFS) cells and bone-marrow derived mesenchymal stem cells (MSCs) were compared to determine their osteogenic differentiation capacity in both 2D and 3D environments. In 2D culture, the AFS cells produced more mineralized matrix but delayed peaks in osteogenic markers. Cells were also cultured on 3D scaffolds constructed of poly-e-caprolactone for 15 weeks. MSCs differentiated more quickly than AFS cells on 3D scaffolds, but mineralized matrix production slowed considerably after 5 weeks. In contrast, the rate of AFS cell mineralization continued to increase out to 15 weeks, at which time AFS constructs contained 5-fold more mineralized matrix than MSC constructs. Therefore, cell source should be taken into consideration when used for cell therapy, as the MSCs would be a good choice for immediate matrix production, but the AFS cells would continue robust mineralization for an extended period of time. This study demonstrates that stem cell source can dramatically influence the magnitude and rate of osteogenic differentiation in vitro.

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Porous yttria-stabilized zirconia (YSZ) has been regarded as a potential candidate for bone substitute due to its high mechanical strength. However, porous YSZ is biologically inert to bone tissue. It is therefore necessary to introduce bioactive coatings onto the walls of the porous structures to enhance its bioactivity. In this study, porous YSZ scaffolds were prepared using a replication technique and then coated with mesoporous bioglass due to its excellent bioactivity. The microstructures were examined using scanning electron microscopy and the mechanical strength was evaluated via compression test. The biocompatibility and bioactivity were also evaluated using bone marrow stromal cell (BMSC) proliferation test and simulated body fluid test.

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To analyse mechanotransduction resulting from tensile loading under defined conditions, various devices for in vitro cell stimulation have been developed. This work aimed to determine the strain distribution on the membrane of a commercially available device and its consistency with rising cycle numbers, as well as the amount of strain transferred to adherent cells. The strains and their behaviour within the stimulation device were determined using digital image correlation (DIC). The strain transferred to cells was measured on eGFP-transfected bone marrow-derived cells imaged with a fluorescence microscope. The analysis was performed by determining the coordinates of prominent positions on the cells, calculating vectors between the coordinates and their length changes with increasing applied tensile strain. The stimulation device was found to apply homogeneous (mean of standard deviations approx. 2% of mean strain) and reproducible strains in the central well area. However, on average, only half of the applied strain was transferred to the bone marrow-derived cells. Furthermore, the strain measured within the device increased significantly with an increasing number of cycles while the membrane's Young's modulus decreased, indicating permanent changes in the material during extended use. Thus, strain magnitudes do not match the system readout and results require careful interpretation, especially at high cycle numbers.