New housing supply and residential construction costs in Australia : a panel ECM approach

The supply of new housing in Australia has been experiencing a low increase rate since the 1990s in conjunction with an increasingly strong housing demand. On the contrary, residential construction costs across Australia?s states maintained dramatic increases simultaneously. Economic theory suggests that new housing supply is correlated to the costs of residential constructions. However, few empirical studies have focused on examining this relationship for Australian housing markets. To comprehensively investigate the relationship between the supply of new housing and residential construction costs a function for new housing supply considering the effects of regional heterogeneities is introduced in this study. By estimating a panel error correction model (ECM) applicable for quantifying the correlation with regional heterogeneities, this research identifies that a causal link and a strong correlation exist in between new housing supply and residential construction costs in Australia.

The relationship between milk, mammary adipocytes and ECM in regulating murine mammary gland involution

 This thesis investigated the role of milk, extracellular matrix and mammary adipocytes in regulating mammary gland function during involution in mice and explored the use of an in vitro culture model, the mammosphere model system to study the same.

α2β1 integrin affects metastatic potential of ovarian carcinoma spheroids by supporting disaggregation and proteolysis

Background: Ovarian cancer is characterized by a wide-spread intra-abdominal metastases which represents a major clinical hurdle in the prognosis and management of the disease. A significant proportion of ovarian cancer cells in peritoneal ascites exist as multicellular aggregates or spheroids. We hypothesize that these cellular aggregates or spheroids are invasive with the capacity to survive and implant on the peritoneal surface. This study was designed to elucidate early inherent mechanism(s) of spheroid survival, growth and disaggregation required for peritoneal metastases.

Methods: In this study, we determined the growth pattern and adhesive capacity of ovarian cancer cell lines (HEY and OVHS1) grown as spheroids, using the well established liquid overlay technique, and compared them to a normal ovarian cell line (IOSE29) and cancer cells grown as a monolayer. The proteolytic capacity of these spheroids was compared with cells grown as a monolayer using a gelatin zymography assay to analyze secreted MMP-2/9 in conditioned serum-free medium. The disaggregation of cancer cell line spheroids was determined on extracellular matrices (ECM) such as laminin (LM), fibronectin (FN) and collagen (CI) and the expression of α2, α3, αv, α6 and β1 interin was determined by flow cytometric analysis. Neutralizing antibodies against α2, β1 subunits and α2β1 integrin was used to inhibit disaggregation as well as activation of MMPs in spheroids.

Results: We demonstrate that ovarian cancer cell lines grown as spheroids can sustain growth for 10 days while the normal ovarian cell line failed to grow beyond 2 days. Compared to cells grown as a monolayer, cancer cells grown as spheroids demonstrated no change in adhesion for up to 4 days, while IOSE29 cells had a 2–4-fold loss of adhesion within 2 days. Cancer cell spheroids disaggregated on extracellular matrices (ECM) and demonstrated enhanced expression of secreted pro-MMP2 as well as activated MMP2/MMP9 with no such activation of MMP's observed in monolayer cells. Flow cytometric analysis demonstrated enhanced expression of α2 and diminution of α6 integrin subunits in spheroids
versus monolayer cells. No change in the expression of α3, αv and β1 subunits was evident. Conversely, except for αv integrin, a 1.5–7.5-fold decrease in α2, α3, α6 and β1 integrin subunit expression was observed in IOSE29 cells within 2 days. Neutralizing antibodies against α2, β1 subunits and α2β1 integrin inhibited disaggregation as well as activation of
MMPs in spheroids.

Conclusion: Our results suggest that enhanced expression of α2β1 integrin may influence spheroid disaggregation and
proteolysis responsible for the peritoneal dissemination of ovarian carcinoma. This may indicate a new therapeutic target
for the suppression of the peritoneal metastasis associated with advanced ovarian carcinomas.

Is privatisation good for investment in Australia?

Privatisation was expected to promote investment in the economy as part of improving dynamic efficiency. The relation between aggregate public and private investment in Australia is investigated in an endogeneous ECM framework. Model selection for a simple investment function allows restrictions for neoclassical crowding out or Keynesian crowding in (after Aschauer 1989) in a small open economy. An ECM is estimated including annual aggregate private investment, public investment, income, rate of return, average interest cost, exchange rate and inventories from 1960 to 2005. Public capital appears unresponsive to shocks and crowding out is not evident.

Intracellular drug delivery by sulfatide-mediated liposomes to gliomas

We described here a liposomal carrier system in which the targeting ligand was sulfatide, a glycosphingolipid known to bind several extracellular matrix (ECM) glycoproteins whose expression was highly up-regulated in many tumors. In vitro experiments with human glioma cell lines demonstrated that robust intracellular uptake of the liposomes depended specifically on the presence of sulfatide as the key liposomal component. Significant amount of the liposomes remained largely intact in the cytoplasm for hours following their internalization. When anticancer drug doxorubicin (DOX) was encapsulated in such liposomes, most of the drug was preferably delivered into the cell nuclei to exert its cytotoxicity. Use of this drug delivery system to deliver DOX for treatment of tumor-bearing nude mice displayed much improved therapeutic effects over the free drug or the drug carried by polyethylene glycol (PEG)-grafted liposomes. Our results demonstrate a close link between effective intracellular uptake of the drug delivery system and its therapeutic outcome. Moreover, the sulfatide-containing liposomes (SCL) may represent an interesting ligand-targeted drug carrier for a wide spectrum of cancers in which sulfatide-binding ECM glycoproteins are expressed.

Blood-stage Plasmodium infection induces CD8+ T lymphocytes to parasite-expressed antigens, largely regulated by CD8α+ dendritic cells

Although CD8+ T cells do not contribute to protection against the blood stage of Plasmodium infection, there is mounting evidence that they are principal mediators of murine experimental cerebral malaria (ECM). At present, there is no direct evidence that the CD8+ T cells mediating ECM are parasite-specific or, for that matter, whether parasite-specific CD8+ T cells are generated in response to blood-stage infection. To resolve this and to define the cellular requirements for such priming, we generated transgenic P. berghei parasites expressing model T cell epitopes. This approach was necessary as MHC class I-restricted antigens to blood-stage infection have not been defined. Here, we show that blood-stage infection leads to parasite-specific CD8+ and CD4+ T cell responses. Furthermore, we show that P. berghei-expressed antigens are cross-presented by the CD8α+ subset of dendritic cells (DC), and that this induces pathogen-specific cytotoxic T lymphocytes (CTL) capable of lysing cells presenting antigens expressed by blood-stage parasites. Finally, using three different experimental approaches, we provide evidence that CTL specific for parasite-expressed antigens contribute to ECM.

The ß-amyloid peptide in Alzheimer's disease decreases adhesion of vascular muscle cells to the basement membrane

Cerebral amyloid angiopathy (CAA) is a major feature of Alzheimer's disease pathology. In CAA, degeneration of vascular smooth muscle cells (VSMCs) occurs close to regions of the basement membrane where the amyloid protein (Aβ) builds up. In this study, the possibility that Aβ disrupts adhesive interactions between VSMCs and the basement membrane was examined. VSMCs were cultured on a commercial basement membrane substrate (Matrigel). The presence of Aβ in the Matrigel decreased cell-substrate adhesion and cell viability. Full-length oligomeric Aβ was required for the effect, as N- and C-terminally truncated peptide analogues did not inhibit adhesion. Aβ that was fluorescently labelled at the N-terminus (fluo-Aβ) bound to Matrigel as well as to the basement membrane heparan sulfate proteoglycan (HSPG) perlecan and laminin. Adhesion of VSMCs to perlecan or laminin was decreased by Aβ. As perlecan influences VSMC viability through the extracellular signal-regulated kinase (ERK)1/2 signalling pathway, the effect of Aβ1–40 on ERK1/2 phosphorylation was examined. The level of phospho-ERK1/2 was decreased in cells following Aβ treatment. An inhibitor of ERK1/2 phosphorylation enhanced the effect of Aβ on cell adhesion. The studies suggest that Aβ can decrease VSMC viability by disrupting VSMC–extracellular matrix (ECM) adhesion.

Epidermal growth factor-induced ovarian carcinoma cell migration is associated with JAK2/STAT3 signals and changes in the abundance and localization of α6β1 integrin

Peritoneal dissemination of ovarian carcinoma is mediated by epithelial–mesenchymal interconversions leading to the disruption of cell–cell contact and modulation of cell–extracellular matrix (ECM) interactions. The present study was designed to evaluate the effects of epidermal growth factor (EGF) as a modulator of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) signalling and changes in integrin expression during the process similar to EMT. A fibroblastic morphology with reduced intercellular cell contacts and increased cell motility was observed in ovarian cancer cell lines in response to EGF and was concomitant with the up regulation of EMT-associated N-cadherin and vimentin expression. These changes were accompanied by an increase in α2, α6 and β1 integrin subunits and activation of JAK2 and STAT3 signalling which was suppressed by a specific JAK2 inhibitor. Consistent with the suppression of STAT3 activity, N-cadherin and vimentin expression were abrogated and was coherent with the loss of cell motility and the expression of α6 and β1 integrin subunits. Neutralizing antibodies against α6 and β1 subunits inhibited cancer cell migration. A strong correlation between the expression of N-cadherin, vimentin and JAK2/STAT3 levels were detected in high-grade ovarian tumors and was consistent with the previously reported enhanced expression of α6 integrin subunit in advanced tumors [Ahmed N, Riley C, Oliva K, Rice G, Quinn M. Ascites induces modulation of α6β1 integrin and urokinase plasminogen activator receptor expression and associated functions in ovarian carcinoma. British Journal of Cancer 2005;92:1475–85]. Our data incorporating the clinical samples and the cancer cell lines is the first to demonstrate that JAK2/STAT3 pathway may be one of the downstream events in EMT-like process and α6β1 integrin-mediated signalling in ovarian carcinomas.

Immune-mediated mechanisms of parasite tissue sequestration during experimental cerebral malaria

Cerebral malaria is a severe complication of malaria. Sequestration of parasitized RBCs in brain microvasculature is associated with disease pathogenesis, but our understanding of this process is incomplete. In this study, we examined parasite tissue sequestration in an experimental model of cerebral malaria (ECM). We show that a rapid increase in parasite biomass is strongly associated with the induction of ECM, mediated by IFN-γ and lymphotoxin α, whereas TNF and IL-10 limit this process. Crucially, we discovered that host CD4+ and CD8+ T cells promote parasite accumulation in vital organs, including the brain. Modulation of CD4+ T cell responses by helminth coinfection amplified CD4+ T cell-mediated parasite sequestration, whereas vaccination could generate CD4+ T cells that reduced parasite biomass and prevented ECM. These findings provide novel insights into immune-mediated mechanisms of ECM pathogenesis and highlight the potential of T cells to both prevent and promote infectious diseases.

Effects of replication on measured S-N curves of metals

Replication, or repeated tests at the same stress amplitude, is used to provide statistical confidence in life data during the development of S-N curves. This paper discusses the effects of replication on the measurement of S-N curves and presents an alternative to traditional replication methods for the determination of S-N curves, particularly for the development of preliminary S-N curves. Using specimens made out of the extruded bars of a magnesium alloy, it is demonstrated that the S-N curve estimated using the data from non-replication tests is almost same as that from replication tests. The advantage of using non-replication fatigue tests is that it uses fewer specimens, in this instance, only half of that required for 50% replication fatigue test, to achieve the same estimation as that of the replication fatigue tests. Another advantage of using non-replication fatigue tests is that it can detect the non-linearity using limited specimens.

Replication of hematopoietic stem cell niche

This thesis models the hematopoietic stem cell (HSC) niche by using decellularized extracellular matrix (ECM) scaffolds prepared by MS-5 cell line. The ECM replicates many of the properties of HSC niches in vivo, providing insights into expansion of HSCs that may have several applications in translational medicine.

Current protein-based anti-angiogenic therapeutics

 Angiogenesis is a complex multistep process of formation of new blood vessels. Interactions between several cellular factors including growth factors, cytokines and haematopoietic factors lead to activation of various cellular pathways, finally resulting in extracellular matrix (ECM) degradation, endothelial cell proliferation, survival and migration. Normally, angiogenesis is an essential requirement for vascular development in growing embryos as well as in adult tissues, where this process depends on the intricate balance between the activities of the pro- and anti-angiogenic factors. Abnormal angiogenesis results in aberrant vasculature leading to various pathological conditions. The most important factor implicated in angiogenic processes in vascular endothelial growth factor (VEGF) and its family of ligands and receptors. Several anti-angiogenic drugs have been developed and many more are currently in different phases of clinical trials, which target various angiogenesis-inducing agents, including VEGF, VEGF receptors, angiopoietins and ECM components such as integrins. Anti-angiogenic therapy can be divided into gene-based therapy and protein-based therapy. Gene-based therapies include use of antisense oligonucleotides, siRNA, aptamers, catalytic oligonucleotides including ribozymes and DNAzymes and transcription decoys. Protein-based therapeutics includes monoclonal antibodies, peptidomimetics, fusion proteins and decoy receptors. The later class of therapeutics has several advantages over gene-based and small molecule drugs, including specificity and complexity in functions, better tolerability, less interference with normal biological processes and lesser adverse effects due to decreased immune response by virtue of being mostly body's natural proteins. This review provides a comprehensive overview of angiogenesis and on the current protein-based anti-angiogenic therapeutics under research and in the clinic.

Self-assembled peptide nanostructures for the fabrication of cell scaffolds

The fabrication of artificial scaffolds that effectively mimic the host environment of the cell have exciting potential for the treatment of many diseases in regenerative medicine. In particular, appropriately designed scaffolds have the capacity to support, replace, and mediate the transplantation of therapeutic cells in order to regenerate damaged or diseased tissues. To achieve these goals for regeneration, the engineering of an environment structurally similar to the native extracellular matrix (ECM) is necessary in order to closely match the chemical and physical conditions found within the extracellular niche. Recently, self-assembled peptide (SAP) hydrogels have shown great potential for such biological applications due to their inherent biocompatibility, propensity to form higher order structures, rich chemical functionality and ease of synthesis. Importantly, it is possible to control the organization and properties of the target materials as the chemical structure is determined by amino acid sequence. Here, the development of SAP hydrogels as functional cell scaffolds and useful tools in tissue engineering is reviewed.

Characterisation of minimalist co-assembled fluorenylmethyloxycarbonyl self-assembling peptide systems for presentation of multiple bioactive peptides

The nanofibrillar structures that underpin self-assembling peptide (SAP) hydrogels offer great potential for the development of finely tuned cellular microenvironments suitable for tissue engineering. However, biofunctionalisation without disruption of the assembly remains a key issue. SAPS present the peptide sequence within their structure, and studies to date have typically focused on including a single biological motif, resulting in chemically and biologically homogenous scaffolds. This limits the utility of these systems, as they cannot effectively mimic the complexity of the multicomponent extracellular matrix (ECM). In this work, we demonstrate the first successful co-assembly of two biologically active SAPs to form a coassembled scaffold of distinct two-component nanofibrils, and demonstrate that this approach is more bioactive than either of the individual systems alone. Here, we use two bioinspired SAPs from two key ECM proteins: Fmoc-FRGDF containing the RGD sequence from fibronectin and Fmoc-DIKVAV containing the IKVAV sequence from laminin. Our results demonstrate that these SAPs are able to co-assemble to form stable hybrid nanofibres containing dual epitopes. Comparison of the co-assembled SAP system to the individual SAP hydrogels and to a mixed system (composed of the two hydrogels mixed together post-assembly) demonstrates its superior stable, transparent, shear-thinning hydrogels at biological pH, ideal characteristics for tissue engineering applications. Importantly, we show that only the coassembled hydrogel is able to induce in vitro multinucleate myotube formation with C2C12 cells. This work illustrates the importance of tissue engineering scaffold functionalisation and the need to develop increasingly advanced multicomponent systems for effective ECM mimicry.

STATEMENT OF SIGNIFICANCE: Successful control of stem cell fate in tissue engineering applications requires the use of sophisticated scaffolds that deliver biological signals to guide growth and differentiation. The complexity of such processes necessitates the presentation of multiple signals in order to effectively mimic the native extracellular matrix (ECM). Here, we establish the use of two biofunctional, minimalist self-assembling peptides (SAPs) to construct the first co-assembled SAP scaffold. Our work characterises this construct, demonstrating that the physical, chemical, and biological properties of the peptides are maintained during the co-assembly process. Importantly, the coassembled system demonstrates superior biological performance relative to the individual SAPs, highlighting the importance of complex ECM mimicry. This work has important implications for future tissue engineering studies.