Dr. David Leavesley, BSc (Hons 1A), PhD. - Skin Research Institute of Singapore - Professor

Dr. David Leavesley

BSc (Hons 1A), PhD.

Skin Research Institute of Singapore

Professor

Singapore | Singapore

Main Specialties: Other

Additional Specialties: Cell Biology, Wound Healing, Cell Physiology, Tissue Repair

ORCID logohttps://orcid.org/0000-0002-1033-5459


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Dr. David Leavesley, BSc (Hons 1A), PhD. - Skin Research Institute of Singapore - Professor

Dr. David Leavesley

BSc (Hons 1A), PhD.

Introduction

David Leavesley has an extensive background in tissue repair and regeneration, reflecting his long-standing interest in how cells interact with each other and work together to create living breathing human beings. His research has focussed on creating affordable and useable solutions to address unmet clinical needs experienced by both patients and care-providers. He has made instrumental contributions to several key technology innovations that have informed research, diagnosis and delivered improved clinical outcomes for individuals with hard-to-heal wounds.
He is currently engaged in several commercially focussed R&D projects to develop authentic live ex vivo human model tissues in collaboration with several MNC, LLE and SME partners.
Research teams in which he has leadership roles have been awarded competitive grant funds ~SG$48M, ~AU$11M.
Notable Outcomes
EnteroVax™ recombinant vaccine technology (WO/1985/003521), for enteric diseases, owned by Mayne Pharma International Pty Ltd. AUS
Transwell™ technology for cell migration and organotypic cultivation, owned by Corning Inc. USA.
VitroGro™ technology (WO/2002/024219) for wound healing, skin repair, cell culture and tissue replacement, owned by QUT, licensed to Factor Therapeutics Ltd, AUS (listed on ASX and FWB with current market cap of AU$~50M).
P4 Diagnostics Pte Ltd for technology enabling diagnosis of soft tissue injury from urine.
He has supervised 25 PhD, 3 MSc, 23 Hons, graduate research students to completion.

Primary Affiliation: Skin Research Institute of Singapore - Singapore , Singapore

Specialties:

Additional Specialties:


View Dr. David Leavesley’s Resume / CV

Education

Jan 2001
Centre of Immunology and Cancer Research
Post-Doctoral Fellow
Transplantation immunology
Jan 1995
Royal Adelaide Hospital
Post-Foctoral Fellow
Renal transplanation
Jan 1989 - Dec 1992
Scripps Research Institute
Post-Doctoral Fellow
Immunology
Jan 1992
Hanson Institute of Medical Research
Post-Doctoral Fellow
Blood stem cell transplantation
Sep 1984 - Oct 1988
Cancer Research UK
Ph.D.
Epithelial Cell Biology
Sep 1984 - Oct 1988
University College London
Ph.D.
Zoology
Jan 1982
Enterovax Pty Ltd
Research Officer
Oral vaccines for enteric diseases
Feb 1978 - Nov 1980
Flinders University
B.Sc.
Biological Sciecnes

Experience

Jan 2018
Senior Principal Invesitigator
R
Skin Research Institute of SIngapore [A*STAR}
Jul 2015 - Dec 2017
Agency for Science Technology and Research
Senior Principal Investigator
Institute of Medical Biology
Jan 2012 - Jan 2017
Ningxia Medical University
Teaching
General Hospital of Ningxia Medical University
Jul 2015 - Jul 2015
Senior Principal Investigator
R
Institute of Medical Biology [A*STAR]
Aug 2007
Associate Professor
Teaching, R
School of Biomedical Sciences, QUT
Jan 2001 - Aug 2004
Queensland University of Technology
Lecturer
Life Sciences
Aug 2004
Senior Lecturer
Teaching, R
School of Life Sciences, QUT
Jan 1992 - Jan 2001
University of Adelaide
Senior Lecturer
Medicine
Jan 2001
Lecturer
Teaching, R
School of Life Sciences, QUT
Feb 2000 - Nov 2000
University of Queensland
Research Officer
Centre for Immunology and Cancer Research
Jan 1996 - Dec 1999
Royal Adelaide Hospital
Research Scientist
Renal Medicine
Jan 1993 - Dec 1995
Institute of Medical and Veterinary Sciences
Research Officer
Haematology
Jan 1989 - Dec 1992
Scripps Research Institute
Research Associate
Immunology
Sep 1984 - Oct 1988
Cancer Research UK
Bursar (Graduate Student)
Jan 1983 - Aug 1984
Enterovax Pty Ltd
Research Officer
R&D
Feb 1982 - Nov 1982
Flinders University
Research Officer
Biological Sciences

Publications

116Publications

1090Reads

40Profile Views

Deep Sequencing MicroRNAs from Extracellular Membrane Vesicles Revealed the Association of the Vesicle Cargo with Cellular Origin.

Int J Mol Sci 2020 Feb 8;21(3). Epub 2020 Feb 8.

School of Biomedical Science, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia.

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http://dx.doi.org/10.3390/ijms21031141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036882PMC
February 2020
2.862 Impact Factor

Characteristics and roles of extracellular vesicles released by epidermal keratinocytes.

J Eur Acad Dermatol Venereol 2019 Dec 9;33(12):2264-2272. Epub 2019 Sep 9.

School of Biomedical Science, Faculty of Health, Queensland University of Technology, Brisbane, Qld, Australia.

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http://dx.doi.org/10.1111/jdv.15859DOI Listing
December 2019
3 Reads
2.826 Impact Factor

Wound Healing and the Use of Medicinal Plants.

Evid Based Complement Alternat Med 2019 22;2019:2684108. Epub 2019 Sep 22.

Skin Research Institute of Singapore, Agency for Science, Technology and Research, A∗STAR, 11 Mandalay Road, Singapore 308232.

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http://dx.doi.org/10.1155/2019/2684108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778887PMC
September 2019
1.880 Impact Factor

Application of "macromolecular crowding" in vitro to investigate the naphthoquinones shikonin, naphthazarin and related analogues for the treatment of dermal scars.

Chem Biol Interact 2019 Sep 10;310:108747. Epub 2019 Jul 10.

Skin Research Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore.

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http://dx.doi.org/10.1016/j.cbi.2019.108747DOI Listing
September 2019
11 Reads
2.577 Impact Factor

Menstrual fluid factors facilitate tissue repair: identification and functional action in endometrial and skin repair.

FASEB J 2019 01 23;33(1):584-605. Epub 2018 Jul 23.

The Hudson Institute of Medical Research, Clayton, Victoria, Australia.

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http://dx.doi.org/10.1096/fj.201800086RDOI Listing
January 2019
30 Reads
5.043 Impact Factor

Differential Expression of Keratinocyte-Derived Extracellular Vesicle Mirnas Discriminate Exosomes From Apoptotic Bodies and Microvesicles.

Front Endocrinol (Lausanne) 2018 11;9:535. Epub 2018 Sep 11.

Tissue Repair and Translational Physiology Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia.

Extracellular vesicles (EVs) are mammalian cell-derived nano-scale structures enclosed by a lipid bilayer that were previously considered to be cell debris with little biological value. However, EVs are now recognized to possess biological function, acting as a packaging, transport and delivery mechanisms by which functional molecules (i.e., miRNAs) can be transferred to target cells over some distance. To examine the miRNA from keratinocyte-derived EVs, we isolated three distinct populations of EVs from both HaCaT and primary human keratinocytes (PKCs) and characterized their biophysical, biochemical and functional features by using microscopy, immunoblotting, nanoparticle tracking, and next generation sequencing. We identified 1,048; 906; and 704 miRNAs, respectively, in apoptotic bodies (APs), microvesicles (MVs) and exosomes (EXs) released from HaCaT, and 608; 506; and 622 miRNAs in APs, MVs and EXs released from PKCs. In which, there were 623 and 437 identified miRNAs common to three HaCaT-derived EVs and PKC-derived EVs, respectively. In addition, we found hundreds of exosomal miRNAs that were previously un-reported. Differences in the abundance levels of the identified EV miRNAs could discriminate between the three EV populations. These data contribute substantially to knowledge within the EV-identified miRNA database, especially with regard to keratinocyte-derived EV miRNA content.

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http://dx.doi.org/10.3389/fendo.2018.00535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143807PMC
September 2018
14 Reads
3.519 Impact Factor

Xanthine Oxidoreductase: A Novel Therapeutic Target for the Treatment of Chronic Wounds?

Adv Wound Care (New Rochelle) 2018 Mar;7(3):95-104

Institute of Medical Biology, Agency for Science, Technology and Research, Singapore, Singapore.

Chronic wounds are a major burden to patients and to healthcare systems worldwide. These wounds are difficult to heal and treatment is often lengthy and expensive. This has led to research efforts focussed on the wound environment attempting to understand the underlying pathological mechanisms of impaired wound healing. While some of this research has translated to advancements in wound therapies and implementation of new treatment options, chronic wounds remain a significant challenge to treat. Thus, identification of effective, low-cost, advanced wound therapies that enhance healing rates of these problematic wounds is still essential. Xanthine oxidoreductase (XOR), a molybdoflavin enzyme, is emerging as an important source of reactive oxygen species (ROS) in various pathologies, including diabetes and chronic wounds. XOR has recently been shown to be upregulated in chronic wounds, stimulating the overproduction of ROS during dysfunctional wound healing. XOR-induced ROS can amplify and potentiate inflammation in the wound environment further delaying wound closure. The detrimental role of XOR in impaired healing indicates it may be a therapeutic target. Targeted inhibition of XOR has been shown to reduce the expression and activity of this enzyme in diabetic wound models. In turn, this resulted in a significant decrease in ROS levels in the wound environment and improved wound healing. Therefore, repurposing existing XOR inhibitors that are approved for human use may be able to restore homeostasis at the wound site and enable damaged tissue to return to normal healing.

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http://dx.doi.org/10.1089/wound.2016.0724DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833883PMC
March 2018
21 Reads
5.200 Impact Factor

Xanthine Oxidoreductase – A novel therapeutic target for the treatment of chronic wounds.

Advances in Wound Care 7: 95-104. 2018

Advances in Wound Care

Significance: Chronic wounds are a major burden to patients and to healthcare systems worldwide. These wounds are difficult to heal and treatment is often lengthy and expensive. This has led to research efforts focussed on the wound environment attempting to understand the underlying pathological mechanisms of impaired wound healing. While some of this research has translated to advancements in wound therapies and implementation of new treatment options, chronic wounds remain a significant challenge to treat. Thus, identification of effective, low-cost, advanced wound therapies that enhance healing rates of these problematic wounds is still essential. Recent Advances and Critical Issues: Xanthine oxidoreductase (XOR), a molybdoflavin enzyme, is emerging as an important source of reactive oxygen species (ROS) in various pathologies, including diabetes and chronic wounds. XOR has recently been shown to be upregulated in chronic wounds, stimulating the overproduction of ROS during dysfunctional wound healing. XOR-induced ROS can amplify and potentiate inflammation in the wound environment further delaying wound closure. Future Directions: The detrimental role of XOR in impaired healing indicates it may be a therapeutic target. Targeted inhibition of XOR has been shown to reduce the expression and activity of this enzyme in diabetic wound models. In turn, this resulted in a significant decrease in ROS levels in the wound environment and improved wound healing. Therefore, repurposing existing XOR inhibitors that are approved for human use may be able to restore homeostasis at the wound site and enable damaged tissue to return to normal healing.

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March 2018
17 Reads

Skin Tissue Engineering

Comprehensive Biomaterials II, 2nd Edition. Reference Module in Materials Science and Materials Engineering. Eds. P Ducheyne, K Healy, DE Hutmacher, DW Grainger, CJ Kirkpatrick. Vol. 6, Ch. 20, pp 334–382, 1 June, 2017. Elsevier. DOI: 10.1016/B978-0-12-803581-8.10157-2

Comprehensive Biomaterials II

The integration of healing, cell biology, and skin tissue engineering research has been ongoing for nearly one century. In this chapter, we provide a bird's eye view of skin anatomy and functions, wound healing processes, the challenges and solutions to wound healing. Many techniques and biomaterials have been examined for their potential utility as skin substitutes. Notwithstanding evidence that some strategies have been more successful than others, the ideal skin substitute does not exist. Existing skin substitutes suffer from poor mechanical properties, poor biocompatibility, poor immunocompatibility, poor integration, limited vascularization (poor survival), and fibrosis (scarring). However, the results from collaborative efforts between skin biologists, materials engineers and surgeons is providing transforming advances in this field and is delivering improvements for skin repair and regeneration. The combination of stem cells, vascularization, smart materials and customized bioprinting means that authentic skin substitutes that support skin regeneration are visible on the horizon.

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December 2017
10 Reads

A fence barrier method of leading edge cell capture for explorative biochemical research.

Cell Adh Migr 2017 Sep 17;11(5-6):496-503. Epub 2017 Feb 17.

a Wound Management Innovation Cooperative Research Centre , Australia.

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http://dx.doi.org/10.1080/19336918.2016.1269997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5810785PMC
September 2017
13 Reads
4.505 Impact Factor

Investigating the potential of Oxymatrine as a psoriasis therapy.

Chem Biol Interact 2017 Jun 25;271:59-66. Epub 2017 Apr 25.

Tissue Organ Bank & Tissue Engineering Centre, General Hospital of Ningxia Medical University, Ningxia, China; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia. Electronic address:

Psoriasis vulgaris is a chronic inflammatory skin disease, stubbornly intractable, with substantial consequences for patient physical and mental welfare. Approaches currently available to treat psoriasis are not satisfactory due to undesirable side-effects or expense. Psoriasis is characterized by hyperproliferation and inflammation. Oxymatrine, an active component extracted from Sophora flavescens, has been demonstrated to possess anti-proliferation, anti-inflammatory, anti-tumorigenic, immune regulation and pro-apoptotic properties. This investigation presents a detailed retrospective review examining the effect of Oxymatrine on psoriasis and investigates the mechanisms underlying patient responses to Oxymatrine. We confirm that Oxymatrine administration significantly reduced the Psoriasis Area Severity Index score, with high efficacy compared to the control group. In addition, we have found that Oxymatrine significantly inhibits the viability, proliferation and differentiation of human keratinocyte in vitro. Immunohistochemical analysis indicates Oxymatrine significantly suppresses the expression of Pan-Cytokeratin, p63 and keratin 10. The results indicate that the suppression of p63 expression may lead to the anti-proliferation effect of Oxymatrine on human skin keratinocytes. Oxymatrine does not affect the formation of basement membrane, which is very important to maintain the normal function of human skin keratinocytes. In summary, Oxymatrine offers an effective, economical, and safe treatment for patients presenting with intractable psoriasis vulgaris.

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http://dx.doi.org/10.1016/j.cbi.2017.04.020DOI Listing
June 2017
20 Reads
3.143 Impact Factor

Association of Extracellular Membrane Vesicles with Cutaneous Wound Healing.

Int J Mol Sci 2017 May 1;18(5). Epub 2017 May 1.

Tissue Repair and Translational Physiology Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059, Australia.

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http://dx.doi.org/10.3390/ijms18050956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454869PMC
May 2017
14 Reads
2.862 Impact Factor

Down-Regulation of PER2 Increases Apoptosis of Gliomas after X-Ray Irradiation.

Chemo Open Access 6(2): 228. 2017

Chemo Open Access

Period2 (PER2), a core circadian gene, not only modulates circadian rhythm but also may play an important role in other biological processes including pathways involved in the proliferation and apoptosis of tumor cells. In this study, we investigated the mechanism by which downregulated expression of PER2 promotes apoptosis of wild-type TP53 human glioma U343 cells exposed to X-rays. U343 cells were irradiated with 6mV 10Gy X-ray irradiation after infection with shRNA lentivirus to reduce expression of PER2, and then analyzed by several methods such as SCGE analysis, flow cytometry, RT-PCR, and western blotting. Compared with controls, U343 cells expressing low levels of PER2 showed serious DNA damage when exposed to X-ray irradiation in SCGE analysis (P<0.05), and higher death rates in flow cytometry assay (P<0.05). RT-PCR and western blot analysis both revealed decreased expression of ATM and TP53, which regulate DNA damage and repair via the ATM-TP53 pathway, and an increased expression of C-MYC, which is related to cell apoptosis. Thus, our research suggests that PER2 may play an important role in tumor radiotherapy, which is attributable to enhanced ATM-TP53 signaling and pro-apoptotic processes. These findings provide a new target for the clinical treatment of glioma, and a reliable basis for postradiation therapy and gene therapy for glioma and other cancers.

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April 2017
17 Reads

Investigating the potential of Oxymatrine as a psoriasis therapy.

Chemico-Biological Interactions 271: 59-66. 2017

Chemico-Biological Interactions

Psoriasis vulgaris is a chronic inflammatory skin disease, stubbornly intractable, with substantial consequences for patient physical and mental welfare. Approaches currently available to treat psoriasis are not satisfactory due to undesirable side-effects or expense. Psoriasis is characterized by hyperproliferation and inflammation. Oxymatrine, an active component extracted from Sophora flavescens, has been demonstrated to possess anti-proliferation, anti-inflammatory, anti-tumorigenic, immune regulation and pro-apoptotic properties. This investigation presents a detailed retrospective review examining the effect of Oxymatrine on psoriasis and investigates the mechanisms underlying patient responses to Oxymatrine. We confirm that Oxymatrine administration significantly reduced the Psoriasis Area Severity Index score, with high efficacy compared to the control group. In addition, we have found that Oxymatrine significantly inhibits the viability, proliferation and differentiation of human keratinocyte in vitro. Immunohistochemical analysis indicates Oxymatrine significantly suppresses the expression of Pan-Cytokeratin, p63 and keratin 10. The results indicate that the suppression of p63 expression may lead to the anti-proliferation effect of Oxymatrine on human skin keratinocytes. Oxymatrine does not affect the formation of basement membrane, which is very important to maintain the normal function of human skin keratinocytes. In summary, Oxymatrine offers an effective, economical, and safe treatment for patients presenting with intractable psoriasis vulgaris.

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April 2017
16 Reads

Antagonists of IGF:Vitronectin Interactions Inhibit IGF-I-Induced Breast Cancer Cell Functions.

Mol Cancer Ther 2016 07 9;15(7):1602-13. Epub 2016 May 9.

Queensland University of Technology, Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Brisbane, Queensland, Australia. Australian Prostate Cancer Research Centre - Queensland, Institute of Health and Biomedical Innovation, Translational Research Institute, Brisbane, Queensland, Australia.

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http://dx.doi.org/10.1158/1535-7163.MCT-15-0907DOI Listing
July 2016
39 Reads
5.683 Impact Factor

Temporal Tracking of Mineralization and Transcriptional Events Associated with Shell Formation During the Early Life History of Pearl Oyster Pinctada maxima

Curr Biotechnol 4(3): 1-14. 2015

Current Biotechnology

Background: Molluscan larval ontogeny is a highly conserved process comprising three principal developmental stages; trochophore, veliger and metamorphosis into the juvenile. A characteristic that is unique to each of these stages is shell design, termed prodissoconch I, prodissoconch II and dissoconch in bivalves. These shells vary in morphology, mineralogy and microstructure. The discrete temporal transitions in shell biomineralization between these larval stages are utilized in this study to investigate transcriptional involvement in several distinct biomineralization events.

Methods: Scanning electron microscopy, X-ray diffraction and microarray differential gene expression analysis were used to document temporal transitions in morphology, mineralogy and microstructure of larval shells and the genes directing their biomineralization.

Results: P. maxima larvae and juveniles collected throughout post-embryonic ontogenesis are described in terms of mineralogy and microstructure of each shelled stage as well as establishing a timeline for transitions in biomineralization. P. maxima larval samples most representative of these biomineralization distinctions and transitions were analyzed for differential gene expression with the microarray platform PmaxArray 1.0. A number of known shell matrix genes and novel transcripts are reported as differentially expressed in correlation to the mineralization events of P. maxima larval ontogeny. However, only a single transcript, PM066, was noted as being expressed before and after the transition to the adult shell design. No other known/putative adult shell matrix genes from P. maxima were detected in association with the larval shells prodissococh I and II, suggesting that their expression is either below detection limits or an almost entirely different set of genes is potentially responsible for larval and adult shell mineralization.

Conclusion: This interdisciplinary investigation has linked the shell developments of P. maxima larval ontogeny with corresponding gene expression profiles, furthering the elucidation of bivalve development and shell biomineralization.

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March 2016
18 Reads

Shikonin reduces TGF-β1-induced collagen production and contraction in hypertrophic scar-derived human skin fibroblasts.

Int J Mol Med 2015 Oct 31;36(4):985-91. Epub 2015 Jul 31.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4059, Australia.

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http://dx.doi.org/10.3892/ijmm.2015.2299DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4564088PMC
October 2015
16 Reads
1.880 Impact Factor

Functional and mechanistic investigation of Shikonin in scarring.

Chem Biol Interact 2015 Feb 12;228:18-27. Epub 2015 Jan 12.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia.

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http://dx.doi.org/10.1016/j.cbi.2014.12.037DOI Listing
February 2015
28 Reads
2.580 Impact Factor

Differential subcellular and extracellular localisations of proteins required for insulin-like growth factor- and extracellular matrix-induced signalling events in breast cancer progression.

BMC Cancer 2014 Aug 29;14:627. Epub 2014 Aug 29.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1186/1471-2407-14-627DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158058PMC
August 2014
47 Reads
3.362 Impact Factor

Multiple types of data are required to identify the mechanisms influencing the spatial expansion of melanoma cell colonies.

BMC Syst Biol 2013 Dec 12;7:137. Epub 2013 Dec 12.

Mathematical Sciences, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1186/1752-0509-7-137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878834PMC
December 2013
31 Reads
2.440 Impact Factor

Vitronectin--master controller or micromanager?

IUBMB Life 2013 Oct 13;65(10):807-18. Epub 2013 Sep 13.

Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia.

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http://dx.doi.org/10.1002/iub.1203DOI Listing
October 2013
193 Reads
3.143 Impact Factor

Quantifying the roles of cell motility and cell proliferation in a circular barrier assay.

J R Soc Interface 2013 May 20;10(82):20130007. Epub 2013 Feb 20.

School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1098/rsif.2013.0007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3627085PMC
May 2013
14 Reads

Quantifying the roles of cell motility and cell proliferation in a circular barrier assay

J R Soc Interface 10(82): 2013007. 2013

Journal of the Royal Society Interface

Moving fronts of cells are essential features of embryonic development, wound repair and cancer metastasis. This paper describes a set of experiments to investigate the roles of random motility and proliferation in driving the spread of an initially confined cell population. The experiments include an analysis of cell spreading when proliferation was inhibited. Our data have been analysed using two mathematical models: a lattice-based discrete model and a related continuum partial differential equation model. We obtain independent estimates of the random motility parameter, D, and the intrinsic proliferation rate, λ, and we confirm that these estimates lead to accurate modelling predictions of the position of the leading edge of the moving front as well as the evolution of the cell density profiles. Previous work suggests that systems with a high λ/D ratio will be characterized by steep fronts, whereas systems with a low λ/D ratio will lead to shallow diffuse fronts and this is confirmed in the present study. Our results provide evidence that continuum models, based on the Fisher-Kolmogorov equation, are a reliable platform upon which we can interpret and predict such experimental observations.

http://www.scopus.com/inward/record.url?eid=2-s2.0-84875720521&partnerID=MN8TOARS

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May 2013
19 Reads

A fragment of the LG3 peptide of endorepellin is present in the urine of physically active mining workers: a potential marker of physical activity.

PLoS One 2012 23;7(3):e33714. Epub 2012 Mar 23.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0033714PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3311645PMC
August 2012
38 Reads
3.234 Impact Factor

Effects of oxygen on zonal marker expression in human articular chondrocytes.

Tissue Eng Part A 2012 May 4;18(9-10):920-33. Epub 2012 Jan 4.

Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia.

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http://dx.doi.org/10.1089/ten.TEA.2011.0088DOI Listing
May 2012
12 Reads

Effects of Oxygen on Zonal Marker Expression in Human Articular Chondrocytes

Tissue Eng Part A. 2012 May;18(9-10):920-33. doi: 10.1089/ten.TEA.2011.0088.

Tissue Engineering - Part A

Articular cartilage is organized in depth zones with phenotypically distinct subpopulations of chondrocytes that are exposed to different oxygen tensions. Despite growing evidence of the critical role for oxygen in chondrogenesis, little is known about its effect on chondrocytes from different zones. This study evaluates zonal marker expression of human articular chondrocytes from different zones under various oxygen tensions. Chondrocytes isolated from full-thickness, superficial, and middle/deep cartilage from knee replacement surgeries were expanded and redifferentiated under hypoxic (5% O(2)) or normoxic (20% O(2)) conditions. Differentiation under hypoxia increased expression of hypoxia-inducible factors 1alpha and 2alpha and accumulation of extracellular matrix, particularly in middle/deep chondrocytes, and favored re-expression of proteoglycan 4 by superficial chondrocytes compared with middle/deep cells. Zone-dependent expression of clusterin varied with culture duration. These results demonstrate that zonal chondrocytes retain important phenotypic differences during in vitro cultivation, and that these characteristics can be improved by altering the oxygen environment. However, transcript levels for pleiotrophin, cartilage intermediate layer protein, and collagen type X were similar between zones, challenging their reliability as zonal markers for tissue-engineered cartilage from osteoarthritis patients. Key factors including oxygen tension and cell source should be considered to prescribe zone-specific properties to tissue-engineered cartilage.

http://www.scopus.com/inward/record.url?eid=2-s2.0-84860505717&partnerID=MN8TOARS

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May 2012
15 Reads

Effects of oxygen and culture system on in vitro propagation and redifferentiation of osteoarthritic human articular chondrocytes.

Cell Tissue Res 2012 Mar 4;347(3):649-63. Epub 2011 Jun 4.

Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, QLD 4059, Australia.

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http://dx.doi.org/10.1007/s00441-011-1193-7DOI Listing
March 2012
18 Reads
3.565 Impact Factor

Effects of oxygen and culture system on in vitro propagation and redifferentiation of osteoarthritic human articular chondrocytes

Cell Tissue Res. 2012 Mar;347(3):649-63.

Cell and Tissue Research

Regenerative medicine-based approaches for the repair of damaged cartilage rely on the ability to propagate cells while promoting their chondrogenic potential. Thus, conditions for cell expansion should be optimized through careful environmental control. Appropriate oxygen tension and cell expansion substrates and controllable bioreactor systems are probably critical for expansion and subsequent tissue formation during chondrogenic differentiation. We therefore evaluated the effects of oxygen and microcarrier culture on the expansion and subsequent differentiation of human osteoarthritic chondrocytes. Freshly isolated chondrocytes were expanded on tissue culture plastic or CultiSpher-G microcarriers under hypoxic or normoxic conditions (5% or 20% oxygen partial pressure, respectively) followed by cell phenotype analysis with flow cytometry. Cells were redifferentiated in micromass pellet cultures over 4 weeks, under either hypoxia or normoxia. Chondrocytes cultured on tissue culture plastic proliferated faster, expressed higher levels of cell surface markers CD44 and CD105 and demonstrated stronger staining for proteoglycans and collagen type II in pellet cultures compared with microcarrier-cultivated cells. Pellet wet weight, glycosaminoglycan content and expression of chondrogenic genes were significantly increased in cells differentiated under hypoxia. Hypoxia-inducible factor-3α mRNA was up-regulated in these cultures in response to low oxygen tension. These data confirm the beneficial influence of reduced oxygen on ex vivo chondrogenesis. However, hypoxia during cell expansion and microcarrier bioreactor culture does not enhance intrinsic chondrogenic potential. Further improvements in cell culture conditions are therefore required before chondrocytes from osteoarthritic and aged patients can become a useful cell source for cartilage regeneration.

http://www.scopus.com/inward/record.url?eid=2-s2.0-84859432012&partnerID=MN8TOARS

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March 2012
15 Reads

Adult Human Articular Chondrocytes in a Microcarrier-Based Culture System: Expansion and Redifferentiation

J Orthop Res. 2011 Apr;29(4):539-46. doi: 10.1002/jor.21264.

Journal of Orthopaedic Research

Expanding human chondrocytes in vitro while maintaining their ability to form cartilage remains a key challenge in cartilage tissue engineering. One promising approach to address this is to use microcarriers as substrates for chondrocyte expansion. While microcarriers have shown beneficial effects for expansion of animal and ectopic human chondrocytes, their utility has not been determined for freshly isolated adult human articular chondrocytes. Thus, we investigated the proliferation and subsequent chondrogenic differentiation of these clinically relevant cells on porous gelatin microcarriers and compared them to those expanded using traditional monolayers. Chondrocytes attached to microcarriers within 2 days and remained viable over 4 weeks of culture in spinner flasks. Cells on microcarriers exhibited a spread morphology and initially proliferated faster than cells in monolayer culture, however, with prolonged expansion they were less proliferative. Cells expanded for 1 month and enzymatically released from microcarriers formed cartilaginous tissue in micromass pellet cultures, which was similar to tissue formed by monolayer-expanded cells. Cells left attached to microcarriers did not exhibit chondrogenic capacity. Culture conditions, such as microcarrier material, oxygen tension, and mechanical stimulation require further investigation to facilitate the efficient expansion of clinically relevant human articular chondrocytes that maintain chondrogenic potential for cartilage regeneration applications. 

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December 2011
14 Reads

Human pilot studies reveal the potential of a vitronectin: growth factor complex as a treatment for chronic wounds.

Int Wound J 2011 Oct;8(5):522-32

Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

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http://dx.doi.org/10.1111/j.1742-481X.2011.00859.xDOI Listing
October 2011
16 Reads
2.023 Impact Factor

Spatial analysis of biomineralization associated gene expression from the mantle organ of the pearl oyster Pinctada maxima.

BMC Genomics 2011 Sep 21;12:455. Epub 2011 Sep 21.

Faculty of Science and Technology, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4000, Australia.

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http://dx.doi.org/10.1186/1471-2164-12-455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3191542PMC
September 2011
9 Reads
3.990 Impact Factor

Spatial analysis of biomineralization associated gene expression from the mantle organ of the pearl oyster Pinctada maxima

BMC Genomics. 2011 Sep 21;12:455. doi: 10.1186/1471-2164-12-455.

BMC Genomics

BACKGROUND:

Biomineralization is a process encompassing all mineral containing tissues produced within an organism. One of the most dynamic examples of this process is the formation of the mollusk shell, comprising a variety of crystal phases and microstructures. The organic component incorporated within the shell is said to dictate this architecture. However general understanding of how this process is achieved remains ambiguous. The mantle is a conserved organ involved in shell formation throughout molluscs. Specifically the mantle is thought to be responsible for secreting the protein component of the shell. This study employs molecular approaches to determine the spatial expression of genes within the mantle tissue to further the elucidation of the shell biomineralization.

RESULTS:

A microarray platform was custom generated (PmaxArray 1.0) from the pearl oyster Pinctada maxima. PmaxArray 1.0 consists of 4992 expressed sequence tags (ESTs) originating from mantle tissue. This microarray was used to analyze the spatial expression of ESTs throughout the mantle organ. The mantle was dissected into five discrete regions and analyzed for differential gene expression with PmaxArray 1.0. Over 2000 ESTs were determined to be differentially expressed among the tissue sections, identifying five major expression regions. In situ hybridization validated and further localized the expression for a subset of these ESTs. Comparative sequence similarity analysis of these ESTs revealed a number of the transcripts were novel while others showed significant sequence similarities to previously characterized shell related genes.

CONCLUSIONS:

This investigation has mapped the spatial distribution for over 2000 ESTs present on PmaxArray 1.0 with reference to specific locations of the mantleExpression profile clusters have indicated at least five unique functioning zones in the mantle. Three of these zones are likely involved in shell related activities including formation of nacre, periostracum and calcitic prismatic microstructure. A number of novel and known transcripts have been identified from these clusters. The development of PmaxArray 1.0, and the spatial map of its ESTs expression in the mantle has begun characterizing the molecular mechanisms linking the organics and inorganics of the molluscan shell.

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September 2011
16 Reads

Hyaluronic acid: evaluation as a potential delivery vehicle for vitronectin:growth factor complexes in wound healing applications.

J Control Release 2011 Aug 30;153(3):225-32. Epub 2011 Mar 30.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.

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http://dx.doi.org/10.1016/j.jconrel.2011.03.021DOI Listing
August 2011
17 Reads
7.705 Impact Factor

Lessons from a 3D human skin equivalent model

Authors:
David Leavesley

38th Annual Meeting of the Society-for-Cutaneous-Ultrastructure-Research

Experimental Dermatology

The repair and regeneration of human skin is characterised as a cascade of overlapping biochemical, physiological and morphological events. The inter-dependency of these events introduces complexity into what superficially appears to be, a simple process. These intrinsic complexities represent substantial technical challenges to our interrogation and understanding of the biology that underlies this essential process. In contrast to the convenient rodent models that provide the tractable test-platform for immunologists and pharmacologists, few animals repair skin in the same way humans do. While rodents repair predominantly by dermal contraction, humans repair primarily by re-epithelialisation. In order to undertake pre-clinical research studies of human skin repair, we have developed a tractable three-dimensional human skin equivalent (HSE) model that can be customised for a variety of skin-related applications. We have utilised the HSE model to demonstrate functional cellular responses to reagents that aid skin repair and regeneration. Diverse clinical pathologies can be recapitulated and the tissue's response(s) to medical and pharmacological interventions evaluated. The HSE provides a convenient tractable platform-technology that is suitable for structural, functional and physiological interrogation of living human skin tissue.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000295012600007&KeyUID=WOS:000295012600007

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August 2011
15 Reads

Adult human articular chondrocytes in a microcarrier-based culture system: expansion and redifferentiation.

J Orthop Res 2011 Apr 18;29(4):539-46. Epub 2010 Oct 18.

Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.

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http://dx.doi.org/10.1002/jor.21264DOI Listing
April 2011
46 Reads
2.990 Impact Factor

Insulin-like growth factor-I:vitronectin complex-induced changes in gene expression effect breast cell survival and migration.

Endocrinology 2011 Apr 8;152(4):1388-401. Epub 2011 Feb 8.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, 4059, Queensland, Australia.

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http://dx.doi.org/10.1210/en.2010-0897DOI Listing
April 2011
16 Reads
4.503 Impact Factor

Mechanistic investigations into interactions between IGF-I and IGFBPs and their impact on facilitating cell migration on vitronectin

Growth Factors. 2010 Oct;28(5):359-69. doi: 10.3109/08977194.2010.494603.

Growth Factors

Numerous studies have reported links between insulin-like growth factors (IGFs) and the extra-cellular matrix protein vitronectin (VN). We ourselves have reported that IGF-I binds to VN via IGF-binding proteins (IGFBPs) to stimulate HaCaT and MCF-7 cell migration. Here, we detail the functional evaluation of IGFBP-1, -2, -3, -4 and -6 in the presence and absence of IGF-I and VN. The data presented here, combined with our prior data on IGFBP-5, suggest that IGFBP-3, -4 and -5 are the most effective at stimulating cell migration in combination with IGF-I and VN. In addition, we demonstrate that different regions within IGFBP-3 and -4 are critical for complex formation. Furthermore, we examine whether multi-protein complexes of IGF-I and IGFBPs associated with fibronectin and collagen IV are also able to enhance functional biological responses.

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December 2010
14 Reads

The effect of amphiphilic siloxane oligomers on fibroblast and keratinocyte proliferation and apoptosis.

J Biomed Mater Res A 2010 Nov;95(2):620-31

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.

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http://dx.doi.org/10.1002/jbm.a.32844DOI Listing
November 2010
18 Reads
3.370 Impact Factor

Development of a three-dimensional human skin equivalent wound model for investigating novel wound healing therapies.

Tissue Eng Part C Methods 2010 Oct;16(5):1111-23

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

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http://eprints.qut.edu.au/39201/2/Development_of_a_Three-Dim
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http://www.liebertonline.com/doi/abs/10.1089/ten.tec.2009.07
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http://dx.doi.org/10.1089/ten.TEC.2009.0725DOI Listing
October 2010
24 Reads

Mechanistic investigations into interactions between IGF-I and IGFBPs and their impact on facilitating cell migration on vitronectin.

Growth Factors 2010 Oct;28(5):359-69

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Queensland, Australia.

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http://dx.doi.org/10.3109/08977194.2010.494603DOI Listing
October 2010
21 Reads
3.390 Impact Factor

A chimeric vitronectin: IGF-I protein supports feeder-cell-free and serum-free culture of human embryonic stem cells.

Stem Cells Dev 2010 Sep;19(9):1297-305

Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia.

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http://dx.doi.org/10.1089/scd.2009.0504DOI Listing
September 2010
11 Reads
3.730 Impact Factor

Vitronectin modulates human mesenchymal stem cell response to insulin-like growth factor-I and transforming growth factor beta 1 in a serum-free environment.

Tissue Eng Part A 2009 Jun;15(6):1415-26

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, Australia.

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http://dx.doi.org/10.1089/ten.tea.2007.0431DOI Listing
June 2009
19 Reads

Vitronectin modulates human mesenchymal stem cell response to insulin-like growth factor-I and transforming growth factor beta 1 in a serum-free environment

Tissue Eng Part A. 2009 Jun;15(6):1415-26. doi: 10.1089/ten.tea.2007.0431.

Tissue Engineering - Part A

The use of animal sera for the culture of therapeutically important cells impedes the clinical use of the cells. We sought to characterize the functional response of human mesenchymal stem cells (hMSCs) to specific proteins known to exist in bone tissue with a view to eliminating the requirement of animal sera. Insulin-like growth factor-I (IGF-I), via IGF binding protein-3 or -5 (IGFBP-3 or -5) and transforming growth factor-beta 1 (TGF-beta(1)) are known to associate with the extracellular matrix (ECM) protein vitronectin (VN) and elicit functional responses in a range of cell types in vitro. We found that specific combinations of VN, IGFBP-3 or -5, and IGF-I or TGF-beta(1) could stimulate initial functional responses in hMSCs and that IGF-I or TGF-beta(1) induced hMSC aggregation, but VN concentration modulated this effect. We speculated that the aggregation effect may be due to endogenous protease activity, although we found that neither IGF-I nor TGF-beta(1) affected the functional expression of matrix metalloprotease-2 or -9, two common proteases expressed by hMSCs. In summary, combinations of the ECM and growth factors described herein may form the basis of defined cell culture media supplements, although the effect of endogenous protease expression on the function of such proteins requires investigation.

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June 2009
16 Reads

Functional and phenotypic characterization of human keratinocytes expanded in microcarrier culture.

J Biomed Mater Res A 2009 Jan;88(1):184-94

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia.

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http://dx.doi.org/10.1002/jbm.a.31864DOI Listing
January 2009
17 Reads
3.370 Impact Factor

Functional and phenotypic characterization of human keratinocytes expanded in microcarrier culture

J Biomed Mater Res A. 2009 Jan;88(1):184-94. doi: 10.1002/jbm.a.31864.

Journal of Biomedical Materials Research - Part A

Skin cells for transplantation are routinely prepared by growing patient keratinocytes in a semi-defined cocktail of growth factors, including serum and feeder cells. However, these reagents require substantial risk remediation and can contribute to transplant rejection. Microcarrier culture is an emerging technology that may allow the elimination of feeder cells whilst facilitating expansion of cultured keratinocytes. However, the behavior of keratinocytes in microcarrier culture and the potential of these cells to form an epidermis have been poorly defined. We characterized freshly isolated human keratinocytes cultured on CultiSpher-G microcarriers in the absence of murine feeder cells and assessed the potential of the keratinocytes to form an epidermis in an in vitro model. In a single passage, keratinocytes multiplied 44.9-fold in microcarrier-bioreactor culture in 17 days, whereas two-dimensional cultures reached confluence in 9 days and only expanded 7.4-fold. Histological characterization of keratinocytes on the microcarriers revealed that the cells were randomly distributed within these porous structures, however, not all pores contained cells. High-resolution microcomputed tomography imaging of the microcarriers confirmed limited interconnectivity of the pores. Immunoreactivity of specific epidermal markers was confirmed during cell expansion via immunohistochemistry. Despite the expression of differentiation markers, microcarrier-expanded keratinocytes retained the capacity to form an epidermis, as was evaluated using an in vitro human skin equivalent model. The epidermis formed by microcarrier-expanded keratinocytes in this model exhibited morphology similar to native skin. Significantly, the microcarrier technique successfully eliminates the need for a feeder cell layer and hence facilitates development of an improved culture system.

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January 2009
15 Reads

Multilineage Differentiation Potential of Bone and Cartilage Cells Derived from Explant Culture

The Open Stem Cell Journal. 1(1): 10-19.

The Open Stem Cell Journal

To date, mesenchymal stem cells (MSCs) from various tissues have been reported, but the yield and differentiation potential of different tissue-derived MSCs is still not clear. This study was undertaken in an attempt to investigate the multilineage stem cell potential of bone and cartilage explant cultures in comparison with bone marrow derived mesenchymal stem cells (BMSCs). The results showed that the surface antigen expression of tissue-derived cells was consistent with that of mesenchymal stem cells, such as lacking the hematopoietic and common leukocyte markers (CD34, CD45) while expressing markers related to adhesion (CD29, CD166) and stem cells (CD90, CD105). The tissue-derived cells were able to differentiate into osteoblast, chondrocyte and adipocyte lineage pathways when stimulated in the appropriate differentiating conditions. However, compared with BMSCs, tissue-derived cells showed less capacity for multilineage differentiation when the level of differentiation was assessed in monolayer culture by analysing the expression of tissuespecific genes by reverse transcription polymerase chain reaction (RT-PCR) and histology. In high density pellet cultures, tissue-derived cells were able to differentiate into chondrocytes, expressing chondrocyte markers such as proteoglycans, type II collagen and aggrecan. Taken together, these results indicate that cells derived from tissue explant cultures reserved certain degree of differentiation properties of MSCs .

http://dx.doi.org/10.2174/1876893800901010010

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January 2009
17 Reads

Effects of oxygen on human chondrocyte zonal phenotype

8th World Biomaterials Congress 2008

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2008
14 Reads

Development of defined media for the serum-free expansion of primary keratinocytes and human embryonic stem cells

Tissue Eng Part C Methods. 2008 Sep;14(3):221-32. doi: 10.1089/ten.tec.2007.0428.

Tissue Engineering - Part C: Methods

Primary keratinocyte (Kc) cells and human embryonic stem (hES) cells are routinely propagated on a mouse fibroblast feeder layer in media containing fetal bovine serum or other nondefined factors. One disadvantage of using these nondefined factors is that they may inadvertently contaminate the culture system with infectious agents; thus, there remains a need to develop safe culture conditions free from poorly defined and/or animal products. Our laboratory has discovered that growth factors (GFs) and vitronectin (VN) can bind to each other resulting in synergistic short-term functional effects in several cell types. The aim of the current study was to determine whether primary Kc and hES cells can be established and serially propagated serum-free using medium containing VN, insulin-like growth factor-I, and insulin-like growth factor binding protein-3 (VN:GF). Here we demonstrate that primary Kc cells can be isolated, established, serially propagated, and re-form an epidermal layer using the VN:GF combination. Additionally, cell proliferation studies indicate that the Kcs proliferate using the VN:GF combination at a rate comparable to cells grown using serum. Similarly, we verified that this VN:GF combination could be employed for the serial propagation of hES cells. Importantly, both the Kc and hES cells retain their undifferentiated phenotype when cultured using the VN:GF combinations as a serum-free medium for up to 4 passages for Kc and at least 10 passages for hES cells as indicated by the expression of a range of cell surface markers. This study demonstrates that the novel, fully defined VN:GF medium is a viable alternative to media containing serum and highlights the potential of this technology for generating therapeutically viable cells and tissues.

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December 2008
17 Reads

Development of defined media for the serum-free expansion of primary keratinocytes and human embryonic stem cells.

Tissue Eng Part C Methods 2008 Sep;14(3):221-32

Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1089/ten.tec.2007.0428DOI Listing
September 2008
27 Reads

Vitronectin: growth factor complexes hold potential as a wound therapy approach.

J Invest Dermatol 2008 Jun 17;128(6):1535-44. Epub 2008 Jan 17.

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.

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http://dx.doi.org/10.1038/sj.jid.5701148DOI Listing
June 2008
13 Reads
7.220 Impact Factor

Vitronectin: Growth factor complexes hold potential as a wound therapy approach

J Invest Dermatol. 2008 Jun;128(6):1535-44. doi: 10.1038/sj.jid.5701148.

Journal of Investigative Dermatology

Topical administration of growth factors has displayed some potential in wound healing, but variable efficacy, high doses, and costs have hampered their implementation. Moreover, this approach ignores the fact that wound repair is driven by interactions between multiple growth factors and extracellular matrix (ECM) proteins. We report herein that complexes comprising IGF and IGF-binding proteins bound to the ECM protein vitronectin (VN) significantly enhance cellular functions relevant to wound repair in human skin keratinocytes in two- and three-dimensional in vitro cell models and are active, even in the presence of wound fluid. Moreover, these responses require activation of both the IGF receptor and the VN-binding alpha(v) integrins. Further, we assessed the complexes as a topical agent in the treatment of deep dermal partial thickness burns in a porcine model. This pilot study revealed that the complexes may hold promise as a wound healing therapy. Critically, the significant responses observed in vitro and the encouraging preliminary data in vivo were obtained with nanogram doses of growth factors. This suggests that coupling delivery of growth factors to ECM proteins such as VN may ultimately prove to be a more effective strategy for developing a wound healing therapy.

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June 2008
18 Reads

Substrate-bound insulin-like growth factor (IGF)-I-IGF binding protein-vitronectin-stimulated breast cell migration is enhanced by coactivation of the phosphatidylinositide 3-Kinase/AKT pathway by alphav-integrins and the IGF-I receptor.

Endocrinology 2008 Mar 13;149(3):1075-90. Epub 2007 Dec 13.

Tissue Repair and Regeneration ProgramInstitute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland 4059, Australia.

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http://dx.doi.org/10.1210/en.2007-0740DOI Listing
March 2008
29 Reads
4.503 Impact Factor

Substrate-bound insulin-like growth factor (IGF)-I-IGF binding protein-vitronectin-stimulated breast cell migration is enhanced by coactivation of the phosphatidylinositide 3-kinase/AKT pathway by αv-integrins and the IGF-I receptor

Endocrinology. 2008 Mar;149(3):1075-90.

Endocrinology

IGF-I can bind to the extracellular matrix protein vitronectin (VN) through the involvement of IGF-binding proteins-2, -3, -4, and -5. Because IGF-I and VN have established roles in tumor cell dissemination, we were keen to investigate the functional consequences of the interaction of IGF-I, IGF binding proteins (IGFBPs), and VN in tumor cell biology. Hence, functional responses of MCF-7 breast carcinoma cells and normal nontumorgenic MCF-10A mammary epithelial cells were investigated to allow side-by-side comparisons of these complexes in both cancerous and normal breast cells. We demonstrate that substrate-bound IGF-I-IGFBP-VN complexes stimulate synergistic increases in cellular migration in both cell types. Studies using IGF-I analogs determined this stimulation to be dependent on both heterotrimeric IGF-I-IGFBP-VN complex formation and the involvement of the IGF-I receptor (IGF-IR). Furthermore, the enhanced cellular migration was abolished on incubation of MCF-7 and MCF-10A cells with function blocking antibodies directed at VN-binding integrins and the IGF-IR. Analysis of the signal transduction pathways underlying the enhanced cell migration revealed that the complexes stimulate a transient activation of the ERK/MAPK signaling pathway while simultaneously producing a sustained activation of the phosphatidylinositide 3-kinase/AKT pathway. Experiments using pharmacological inhibitors of these pathways determined a requirement for phosphatidylinositide 3-kinase/AKT activation in the observed response. Overexpression of wild type and activated AKT further increases substrate-bound IGF-I-IGFBP-VN-stimulated migration. This study provides the first mechanistic insights into the action of IGF-I-IGFBP-VN complexes and adds further evidence to support the involvement of VN-binding integrins and their cooperativity with the IGF-IR in the promotion of tumor cell migration.

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March 2008
14 Reads

Chimeric vitronectin:insulin-like growth factor proteins enhance cell growth and migration through co-activation of receptors.

Growth Factors 2007 Oct;25(5):295-308

Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.

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http://dx.doi.org/10.1080/08977190701803752DOI Listing
October 2007
15 Reads
3.390 Impact Factor

Chimeric vitronectin:insulin-like growth factor proteins enhance cell growth and migration through co-activation of receptors

Growth Factors. 2007 Oct;25(5):295-308. doi: 10.1080/08977190701803752.

Growth Factors

Complexes comprised of IGF-I, IGF-binding proteins and the ECM protein vitronectin (VN) stimulate cell migration and growth and can replace the requirement for serum for the ex vivo expansion of cells, as well as promote wound healing in vivo. Moreover, the activity of the complexes is dependent on co-activation of the IGF-I receptor and VN-binding integrins. In view of this we sought to develop chimeric proteins able to recapitulate the action of the multiprotein complex within a single molecular species. We report here the production of two recombinant chimeric proteins, incorporating domains of VN linked to IGF-I, which mimic the functions of the complex. Further, the activity of the chimeric proteins is dependent on co-activation of the IGF-I- and VN-binding cell surface receptors. Clearly the use of chimeras that mimic the activity of growth factor:ECM complexes, such as these, offer manufacturing advantages that ultimately will facilitate translation to cost-effective therapies.

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October 2007
15 Reads

Surface modification by complexes of vitronectin and growth factors for serum-free culture of human osteoblasts.

Tissue Eng 2005 Nov-Dec;11(11-12):1688-98

Prince Charles Hospital, Brisbane, Queensland, Australia.

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http://dx.doi.org/10.1089/ten.2005.11.1688DOI Listing
April 2006
29 Reads
4.254 Impact Factor

Timing of pulsed electromagnetic field stimulation does not affect the promotion of bone cell development.

Bioelectromagnetics 2005 Dec;26(8):670-6

School of Engineering Systems & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1002/bem.20166DOI Listing
December 2005
10 Reads
1.705 Impact Factor

Timing of pulsed electromagnetic field stimulation does not affect the promotion of bone cell development

Bioelectromagnetics. 2005 Dec;26(8):670-6.

Bioelectromagnetics

Pulsed electromagnetic field (PEMF) devices have been used clinically to promote the healing of surgically resistant fractures in vivo. However, there is a sparsity of data on how the timing of an applied PEMF effects the osteogenic cells that would be present within the fracture gap. The purpose of this study was to examine the response of osteoblast-like cells to a PEMF stimulus, mimicking that of a clinically available device, using four protocols for the timing of the stimulus. The PEMF signal consisted of a 5 ms pulse burst (containing 20 pulses) repeated at 15 Hz. Cultures of a human osteosarcoma cell line, SaOS-2, were exposed to the four timing protocols, each conducted over 3 days. Protocol one stimulated the cells for 8 h each day, protocol two stimulated the cells for 24 h on the first day, protocol three stimulated the cells for 24 h on the second day, and protocol four stimulated the cells for 24 h on the third day. Cells were seeded with either 25,000 or 50,000 cells/well (24-well cell culture plates). All assays showed reduced proliferation and increased differentiation (alkaline phosphatase activity) in the PEMF stimulated cultures compared with the control cultures, except for protocol four alkaline phosphatase measurements. No clear trend was observed between the four protocols; however this may be due to cell density. The results indicated that an osteoblast-like cell line is responsive to a 15 Hz PEMF stimulus, which will stimulate the cell line to into an increasing state of maturity.

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December 2005
14 Reads

Surface modification by complexes of vitronectin and growth factors for serum-free culture of human osteoblasts

Tissue Eng. 2005 Nov-Dec;11(11-12):1688-98.

Tissue Engineering

Cell attachment, expansion, and migration in three-dimensional biomaterials are crucial steps for effective delivery of osteogenic cells into bone defects. Complexes composed of vitronectin (VN), insulin-like growth factors (IGFs), and insulin growth factor-binding proteins (IGFBPs) have been reported to enhance cell attachment, proliferation, and migration in a variety of cell lines in vitro. The aim of this study was to examine whether prebound complexes of VN and IGFs +/- IGFBPs could facilitate human osteoblast serum-free expansion in vitro and enhance cell attachment, proliferation, and migration in three-dimensional biomaterial constructs. Human osteoblasts derived from alveolar bone chips and the established human osteoblast cell line Saos-2 were used. These cells were seeded on tissue culture plates and porous scaffolds of type I collagen sponges and polyglycolic acid (PGA), which had been coated with VN +/- IGFBP-5 +/- IGF-I. Cell attachment, proliferation, and migration were evaluated by cell counting, confocal microscopy, and scanning electron microscopy. The number of attached human osteoblasts was significantly higher in VN-coated polystyrene culture dishes. Furthermore, significant increases in cell proliferation were observed when growth factors were bound to these surfaces in the presence of VN. In the two scaffold materials examined, greater cell attachment was found in type I collagen sponges compared with PGA scaffolds. However, coating the scaffolds with complexes composed of VN + IGF-I or VN + IGFBP-5 + IGF-I enhanced cell attachment on PGA. Moreover, the presence of VN + IGFBP-5 + IGF-I resulted in significantly greater osteoblast migration into deep pore areas as compared with untreated scaffolds or scaffolds treated with fetal calf serum. These results demonstrated that complexes of VN + IGFBP-5 + IGF-I can be used to expand osteoblasts in vitro under serum-free conditions and enhance the attachment and migration of human osteoblasts in three-dimensional culture. This in turn suggests a potential application in surface modification of biomaterials for tissue reconstruction.

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December 2005
15 Reads

In vitro bioactivity of MOEP grafted ePTFE membranes for craniofacial applications.

Biomaterials 2005 Sep;26(26):5303-12

Tissue BioRegeneration and Integration Program, School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane QLD, Australia.

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http://dx.doi.org/10.1016/j.biomaterials.2005.01.061DOI Listing
September 2005
60 Reads
8.560 Impact Factor

In vitro bioactivity of MOEP grafted ePTFE membranes for craniofacial applications

Biomaterials. 2005 Sep;26(26):5303-12.

Biomaterials

The bioactivity of three methacryloyloxyethyl phosphate (MOEP) grafted expanded polytetrafluoroethylene (ePTFE) membranes with varying surface coverage as well as unmodified ePTFE was investigated through a series of in vitro tests: calcium phosphate (CaP) growth in simulated body fluid (SBF), serum protein adsorption, and a morphology and attachment study of human osteoblast-like SaOS-2 cells. The graft copolymers were prepared by means of gamma irradiation induced grafting and displayed various surface morphologies and wettabilities depending on the grafting conditions used. Unmodified ePTFE did not induce nucleation of CaP minerals, whereas all the grafted membranes revealed the growth of CaP minerals after 7 days immersion in SBF. The sample with lowest surface grafting yield (24% coverage), a smooth graft morphology and relatively high hydrophobicity (theta(adv) = 120 degrees, theta(rec) = 80 degrees) showed carbonated hydroxyapatite growth covering the surface. On the other hand, the samples with high surface grafting yield (76% and 100%), a globular graft morphology and hydrophilic surfaces (theta(adv) = 60 degrees and 80 degrees, theta(rec) = 25 degrees and 15 degrees, respectively) exhibited irregular growth of non-apatitic CaP minerals. Irreversibly adsorbed protein measured after a 1h immersion in serum solution was quantified by the amount of nitrogen on the surface using XPS, as well as by weight increase. All grafted membranes adsorbed 3-6 times more protein than the unmodified membrane. The sample with the highest surface coverage adsorbed the most protein. Osteoblast-like SaOS-2 cells cultured for 3 h revealed significantly higher levels of cell attachment on all grafted membranes compared to unmodified ePTFE. Although the morphology of the cells was heterogeneous, in general, the higher grafted surfaces showed a much better cell morphology than both the low surface-grafted and the control unmodified sample. The suite of in vitro tests confirms that a judicious choice of grafted monomer such as the phosphate-containing methacrylate monomer (MOEP) significantly improves the bioactivity of ePTFE in vitro.

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September 2005
14 Reads

QUT Eyes Scarless Healing

David Leavesley, Damien Harkin, Sean McElwain, Graeme George, Zee Upton, 2005, 'QUT Eyes Scarless Healing', Asia-Pacific Biotech News, vol. 09, no. 14

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July 2005
16 Reads

Mediation of biomaterial-cell interactions by adsorbed proteins: a review.

Tissue Eng 2005 Jan-Feb;11(1-2):1-18

Tissue Bioregeneration Domain, Institute of Health and Biomedical Innovation, School of Engineering Systems, Queensland University of Technology, Brisbane, Queensland, Australia.

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http://dx.doi.org/10.1089/ten.2005.11.1DOI Listing
June 2005
30 Reads
4.254 Impact Factor

Responses of keratinocytes to substrate-bound vitronectin: growth factor complexes.

Exp Cell Res 2005 Apr;305(1):221-32

Tissue BioRegeneration and Integration Program, Science Research Centre, School of Life Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.

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http://dx.doi.org/10.1016/j.yexcr.2005.01.004DOI Listing
April 2005
13 Reads
3.250 Impact Factor

Responses of keratinocytes to substrate-bound vitronectin: Growth factor complexes

Exp Cell Res. 2005 Apr 15;305(1):221-32.

Experimental Cell Research

Insulin-like growth factor-1 (IGF-I) can associate with the extracellular matrix protein vitronectin (VN) via select IGF-binding proteins, and the resulting complex stimulates responses in a variety of cell types. As VN can also associate with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), we hypothesized that the multimeric nature of VN could be exploited to deliver multiple growth factors to the cell surface. We report here that VN enhances bFGF but not EGF stimulated [(3)H]-leucine incorporation in the HaCAT keratinocyte cell line, with VN synergistically enhancing cell migration in response to both EGF and bFGF when presented as a VN-bound complex. Furthermore, the addition of EGF and/or bFGF to IGF-I:IGFBP-5:VN complexes significantly enhances both [(3)H]-leucine incorporation and migration of HaCAT cells above that induced by IGF:IGFBP-5:VN complexes alone. Indeed, similar responses are observed in primary cultures of human skin keratinocytes, highlighting the potential use of these novel complexes for a wide range of tissue repair applications.

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April 2005
15 Reads

Potential pitfalls of radiolabel adsorption to ceramic biomaterials.

J Biomed Mater Res A 2005 Mar;72(4):363-72

Tissue BioRegeneration Domain, Institute of Health and Biomedical Innovation and the School of Life Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.

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http://dx.doi.org/10.1002/jbm.a.30247DOI Listing
March 2005
23 Reads
3.370 Impact Factor

Potential pitfalls of radiolabel adsorption to ceramic biomaterials

J Biomed Mater Res A. 2005 Mar 15;72(4):363-72.

Journal of Biomedical Materials Research - Part A

The use of radiolabeled precursor molecules for the metabolic analysis of cell functions is commonplace. Tritiated thymidine, in particular, has been used to quantitate cellular proliferation in numerous cells, including osteoblasts, when cultured on various biomaterials. Our aim was to assess cellular protein synthesis and proliferation, on a range of fluoride ion-substituted hydroxyapatites. Initially, we used a classical metabolic analysis strategy with radiolabeled tracer molecules. Our results suggested that these materials supported enhanced protein synthesis and proliferation of SaOS-2 human osteoblast-like cells. However, control samples also revealed enhanced adsorption of the radiolabeled tracer. We have shown that this arises because partially fluoride ion-substituted hydroxyapatite exhibits enhanced adsorptive characteristics of radiolabeled leucine and thymidine over tissue culture plastic, hydroxyapatite, and fluoroapatite. Moreover, manual cell count data obtained through SEM analysis showed no significant difference in cell proliferation between any of the materials, further indicating that our initial results were artifacts. These results highlight the use and reporting of appropriate cell-free controls are critical in bioassays examining functional responses of cells to biomaterials, and if absent, may confound accurate data interpretation. Our findings have general implications for investigations of cell function on other novel ceramic biomaterials.

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March 2005
17 Reads

Traveling wave model to interpret a wound-healing cell migration assay for human peritoneal mesothelial cells.

Tissue Eng 2004 Mar-Apr;10(3-4):475-82

Centre for Mathematical Biology, Mathematical Institute, University of Oxford, United Kingdom.

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http://dx.doi.org/10.1089/107632704323061834DOI Listing
January 2005
17 Reads
4.254 Impact Factor

Mediation of biomaterial-cell interactions by adsorbed proteins: A review

Tissue Eng. 2005 Jan-Feb;11(1-2):1-18.

Tissue Engineering

An appropriate cellular response to implanted surfaces is essential for tissue regeneration and integration. It is well described that implanted materials are immediately coated with proteins from blood and interstitial fluids, and it is through this adsorbed layer that cells sense foreign surfaces. Hence, it is the adsorbed proteins, rather than the surface itself, to which cells initially respond. Diverse studies using a range of materials have demonstrated the pivotal role of extracellular adhesion proteins--fibronectin and vitronectin in particular--in cell adhesion, morphology, and migration. These events underlie the subsequent responses required for tissue repair, with the nature of cell surface interactions contributing to survival, growth, and differentiation. The pattern in which adhesion proteins and other bioactive molecules adsorb thus elicits cellular reactions specific to the underlying physicochemical properties of the material. Accordingly, in vitro studies generally demonstrate favorable cell responses to charged, hydrophilic surfaces, corresponding to superior adsorption and bioactivity of adhesion proteins. This review illustrates the mediation of cell responses to biomaterials by adsorbed proteins, in the context of osteoblasts and selected materials used in orthopedic implants and bone tissue engineering. It is recognized, however, that the periimplant environment in vivo will differ substantially from the cell-biomaterial interface in vitro. Hence, one of the key issues yet to be resolved is that of the interface composition actually encountered by osteoblasts within the sequence of inflammation and bone regeneration.

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January 2005
15 Reads

Surface properties of bioactivated ePTFE membranes

Transactions - 7th World Biomaterials Congress

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2004
28 Reads

Travelling waves in a wound healing assay

Applied Mathematics Letters. 17(5): 575-580. May 2004

Applied Mathematics Letters

Several authors have predicted that cell propagation in a number of biological contexts, for example, wound healing, tumour cell invasion, angiogenesis etc., occurs due to a constant speed travelling wave of invasion. The analyses of these models to arrive at this prediction is, in many cases, essentially an extension of the classical analysis of Fisher's equation. Here, we show that a very simple wound healing assay does indeed give rise to constant speed travelling waves. To our knowledge, this is the first verification of Fisher's equation in a medical context.

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May 2004
15 Reads

Traveling Wave Model to Interpret a Wound-Healing Cell Migration Assay for Human Peritoneal Mesothelial Cells

Tissue Eng. 2004 Mar-Apr;10(3-4):475-82.

Tissue Engineering

The critical determinants of the speed of an invading cell front are not well known. We performed a "wound-healing" experiment that quantifies the migration of human peritoneal mesothelial cells over components of the extracellular matrix. Results were interpreted in terms of Fisher's equation, which includes terms for the modeling of random cell motility (diffusion) and proliferation. The model predicts that, after a short transient, the invading cell front will move as a traveling wave at constant speed. This is consistent with the experimental findings. Using the model, a relationship between the rate of cell proliferation and the diffusion coefficient was obtained. We used the model to deduce the cell diffusion coefficients under control conditions and in the presence of collagen IV and compared these with other published data. The model may be useful in analyzing the invasive capacity of cancer cells as well in predicting the efficacy of growth factors in tissue reconstruction, including the development of monolayer sheets of cells in skin engineering or the repair of injured corneas using grafts of cultured cells.

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March 2004
18 Reads

Insulin-like growth factor-II bound to vitronectin enhances MCF-7 breast cancer cell migration.

Endocrinology 2003 Jun;144(6):2417-24

Tissue BioRegeneration and Integration Research Program, Center for Molecular Biotechnology, School of Life Sciences, Queensland University of Technology, Brisbane, Queensland 4000, Australia.

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http://dx.doi.org/10.1210/en.2002-221138DOI Listing
June 2003
20 Reads
4.503 Impact Factor

Insulin-like growth factor-II bound to vitronectin enhances MCF-7 breast cancer cell migration

Endocrinology. 2003 Jun;144(6):2417-24.

Endocrinology

We have previously reported that IGF-II binds the extracellular matrix protein vitronectin (VN) with an affinity similar to that for the type-1 IGF receptor (IGF-1R). In view of this finding, and given the cited role of VN in cell motility and adhesion, we aimed to elucidate the functional consequences of this interaction on cellular processes relevant to breast carcinoma. We demonstrate that this complex slightly inhibits cell attachment and has little effect on protein synthesis in MCF-7 breast cancer cells. However, prebinding IGF-II to immobilized VN was found to significantly enhance breast cancer cell migration through Transwells. Interestingly, IGF-II bound to VN, and not IGF-II in solution in the presence of VN, seems to be responsible for the effects on cell migration. Furthermore, studies using analogs of IGF-II with reduced affinity for the IGF-1R or IGF binding proteins indicate that this response involves the IGF-1R but is independent of IGF binding proteins. This is the first study demonstrating that IGF-II:VN complexes enhance migration of cells. This may prove to be especially relevant, given that overexpression of IGF-II and VN are features of many tumors.

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June 2003
16 Reads

VitroGro™ - Novel growth factor complexes for applications in tissue engineering

Third Smith and Nephew International Symposium - Translating Tissue Engineering into Products

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2002
14 Reads

Expression of defensin antimicrobial peptides in the peritoneal cavity of patients on peritoneal dialysis.

Perit Dial Int 2001 Sep-Oct;21(5):501-8

Department of Renal Medicine, Royal Adelaide Hospital, South Australia, Australia.

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April 2002
8 Reads
2.199 Impact Factor

Expression of defensin antimicrobial peptides in the peritoneal cavity of patients on peritoneal dialysis

Perit Dial Int. 2001 Sep-Oct;21(5):501-8.

Peritoneal Dialysis International

OBJECTIVE:

To investigate the expression and regulation of defensins in the peritoneal cavity of peritoneal dialysis (PD) patients.

DESIGN:

The presence of defensins in the peritoneal cavity was assessed using reverse transcription polymerase chain reaction (RT-PCR). In vivo defensin expression was analyzed in human peritoneal membrane biopsies and in peritoneal cavity leukocytes isolated from spent dialysate. Defensin expression in vitro was assessed in cultured human peritoneal mesothelial cells (HPMC) and confirmed with PCR Southern blot and DNA sequencing. The effect of tumor necrosis factor alpha (TNFalpha) and epidermal growth factor (EGF) on beta2 defensin expression in HPMC was analyzed by Northern blot analysis and RT-PCR respectively.

RESULTS:

Both alpha and beta classes of defensins are expressed in the peritoneal cavity of PD patients. Messenger RNA for the alpha-defensin human neutrophil peptide 3 and for beta-defensin-1 (hbetaD-1) were found in preparations containing predominantly peritoneal leukocytes, whereas beta-defensin-2 (hbetaD-2) is expressed by HPMC. HPMC isolated from different individuals displayed variability in both basal hbetaD-2 expression and in response to stimulation by TNFalpha. Conversely, EGF consistently downregulated the level of hbetaD-2 message in HPMC.

CONCLUSION:

Alpha- and beta-defensins are expressed in the peritoneal cavity, and hbetaD-2 is the main defensin present in the peritoneal membrane. Variable levels of expression of hbetaD-2 by mesothelial cells were seen, with evidence of regulation by cytokines and growth factors. This provides evidence for a previously unknown mechanism of innate immunity at that site.

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September 2001
14 Reads

HB-EGF is produced in the peritoneal cavity and enhances mesothelial cell adhesion and migration

Kidney Int. 2001 Feb;59(2):614-24.

Kidney International

BACKGROUND:

The mesothelial cell monolayer lining the peritoneal membrane needs constant repair in response to peritonitis and to the toxicity of peritoneal dialysate. In many continuous ambulatory peritoneal dialysis (CAPD) patients, the repair process progressively fails, and membrane dysfunction and fibrosis occur. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has an important role in wound repair and is also fibrogenic, and thus may be involved in these processes in the peritoneal cavity.

METHODS:

The presence of HB-EGF, its receptors, and its associated proteins was determined in peritoneal membrane biopsies, cultured human peritoneal mesothelial cells (HPMCs), and peritoneal macrophages from CAPD patients by reverse transcription-polymerase chain reaction, flow cytometry, and immunofluorescence immunocytochemistry with confocal microscopy. HB-EGF effects on HPMC adhesion were measured by a static adhesion assay, on integrin expression by flow cytometry, and on migration by wound healing and chemotaxis assays.

RESULTS:

HB-EGF, its receptors HER-1 and HER-4, and the associated proteins CD9, CD44, and integrin alpha(3)beta(1) were expressed by HPMCs and peritoneal macrophages. HB-EGF colocalized with HER-1 and HER-4 in HPMCs and induced their adhesion to collagen type I, expression of beta 1 integrins, and migration.

CONCLUSIONS:

HB-EGF is produced by cells in the peritoneal cavity of CAPD patients and has functional effects on HPMCs that would facilitate repair of the mesothelial layer.

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February 2001
14 Reads

Microfibril-associated glycoprotein-2 specifically interacts with a range of bovine and human cell types via α(v)β 3 integrin

The Journal of Biological Chemistry 274, 13060-13065. doi: 10.1074/jbc.274.19.13060

Journal of Biological Chemistry

Microfibril-associated glycoprotein (MAGP)-1 and MAGP-2 are small structurally related glycoproteins that are specifically associated with fibrillin-containing microfibrils. MAGP-2, unlike MAGP-1, contains an RGD motif with potential for integrin binding. To determine if the RGD sequence is active, a series of cell binding assays was performed. MAGP-2 was shown to promote the attachment and spreading of bovine nuchal ligament fibroblasts when coated onto plastic wells in molar quantities similar to those of fibronectin. In contrast, ∼10-fold more MAGP-1 was required to support comparable levels of cell adhesion. The fibroblast binding to MAGP-2 was completely inhibited if the peptide GRGDSP or the MAGP-2-specific peptide GVSGQRGDDVTTVTSET was added to the reaction medium at a 10 μM final concentration. The control peptide GRGESP had no effect on the interaction. These findings indicate that the cell interaction with MAGP-2 is an RGD-mediated event. A monoclonal antibody to human αVβ3 integrin (LM609) almost completely blocked cell attachment to MAGP-2 when added to the medium at 0.5 μg/ml, whereas two monoclonal antibodies specific for the human β1 integrin subunit, 4B4 (blocking) and QE2.E5 (activating), had no effect even at 10 μg/ml. Fetal bovine aortic smooth muscle cells, ear cartilage chondrocytes, and arterial endothelial cells and human skin fibroblasts and osteoblasts were also observed to adhere strongly to MAGP-2. In addition, each cell type was able to spread on MAGP-2 substrate, with the exception of the endothelial cells, which remained spherical after 2 h of incubation. The binding of each cell type was blocked when the anti-αVβ3 integrin antibody was included in the assay, indicating that αVβ3 integrin is the major receptor for MAGP-2 on several cell types. Thus, MAGP-2 may mediate interactions between fibrillin-containing microfibrils and cell surfaces during the development of a variety of tissues.

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May 1999
16 Reads

Specificity and functional effects of antibodies to human stem cell factor

Growth Factors. 1997;14(1):67-79.

Growth Factors

Three monoclonal antibodies (Mabs), 7H6, 4B10 and Genzyme Mab, and a commercially-available polyclonal antiserum (Genzyme) to human Stem Cell Factor (SCF) were compared for their ability to detect native and recombinant SCF in a variety of assays, and for blocking of SCF function. All antibodies were found to bind to the membrane bound isoform as well as soluble SCF and to bind to both glycosylated (yeast MGF) and unglycosylated (E. coli SCF) recombinant factor. Mabs 7H6 and 4B10, as well as the polyclonal antiserum could immunoprecipitate membrane-associated SCF and all the antibodies could detect recombinant soluble SCF on western blots, although the binding of all except 7H6 was partially sensitive to reduction. Titration of the antibodies on CHO cells expressing membrane-associated human SCF showed similar dose-dependence for all Mabs with 70% of maximum binding seen at 3, 5 and 8 micrograms/ml for 7H6, 4B10 and Genzyme Mab respectively, however the maximum binding seen with 7H6 was approximately 2-fold greater than with 4B10 and 7-fold greater than Genzyme Mab. Competitive binding experiments of the Mabs on cells expressing membrane SCF gave non-reciprocal blocking in all cases with 7H6 completely blocking 4B10 and Genzyme Mab binding. All antibodies except the Genzyme Mab effectively blocked SCF binding to c-Kit-expressing cells, and were strongly inhibitory in an assay of in vitro haemopoiesis which is believed to depend on adhesive interactions, as well as the "classical' cytokine-receptor interaction, mediated by SCF binding to c-Kit.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1997WP73400006&KeyUID=WOS:A1997WP73400006

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January 1997
13 Reads

A novel activating anti-β1 integrin monoclonal antibody binds to the cysteine-rich repeats in the β1 chain

J Biol Chem. 1996 Oct 11;271(41):25099-106.

Journal of Biological Chemistry

The functional status of an integrin depends on the conformation of its extracellular domain, which is controlled by the cell expressing that receptor. The transmission of regulatory signals from within the cell is considered to be via propagated conformational changes from the receptor's cytoplasmic tails to the extracellular ligand binding "pocket." The end result is increased accessibility of the ligand binding pocket in the high affinity ("active") form of integrins. We report a novel monoclonal antibody (QE.2E5) that binds within the cysteine-rich repeats in the integrin beta1 chain and induces high affinity binding of fibronectin to the integrin alpha5beta1. The QE.2E5 epitope is located approximately 200 residues both from the predicted binding site for fibronectin and from the epitopes recognized by other activating anti-beta1 monoclonal antibodies. It is also expressed on beta1 integrins from a number of nonhuman species. Although they have the same functional effects, the binding of QE.2E5 and another activating antibody (8A2) to the receptor have contrasting effects on the expression of an activation-dependent epitope in the beta1 chain. We propose that the cysteine-rich repeats contain a regulatory region that is distinct from those previously described in the integrin beta1 chain.

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October 1996
5 Reads

The mobilization of primitive hemopoietic progenitors into the peripheral blood.

Stem Cells 1994 ;12 Suppl 1:187-201; discussion 201-2

Division of Haematology, Hanson Centre for Cancer Research, Villejuif, France.

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May 1995
6 Reads
6.523 Impact Factor

Cytokines increase human hemopoietic cell adhesiveness by activation of very late antigen (VLA)-4 and VLA-5 integrins

J Exp Med. 1995 May 1;181(5):1805-15.

Journal of Experimental Medicine

Cytokines are known to be important regulators of normal hemopoiesis, acting in concert with components of the bone marrow microenvironment. Interactions with this microenvironment are known to regulate the proliferation, differentiation, and homing of hemopoietic progenitor (CD34+) cells. Adhesive interactions with the extracellular matrix retain CD34+ cells in close proximity to cytokines, but may also provide important costimulatory signals. Thus, the functional states of adhesion receptors are critical properties of CD34+ cells, but the physiological mechanisms responsible for regulating functional properties of cell adhesion receptors on primitive hemopoietic cells are still unknown. We confirm that the integrins very late antigen (VLA)-4 and VLA-5 are expressed on the CD34+ cell lines MO7e, TF1, and on normal bone marrow CD34+ progenitor cells, but in a low affinity state, conferring on them a weak adhesive phenotype on fibronectin (Fn). Herein, we show that the cytokines interleukin (IL)-3, granulocyte-macrophage CSF (GM-CSF), and KIT ligand (KL) are physiological activators of VLA-4 and VLA-5 expressed by MO7e, TF1, and normal bone marrow CD34+ progenitor cells. Cytokine-stimulated adhesion on Fn is dose dependent and transient, reaching a maximum between 15 and 30 min and returning to basal levels after 2 h. This cytokine-dependent activation is specific for VLA-4 and VLA-5, since activation of other beta 1 integrins was not observed. The addition of second messenger antagonists staurosporine and W7 abolished all cytokine-stimulated adhesion to Fn. In contrast, genistein inhibited KL-stimulated adhesion, but failed to inhibit GM-CSF- and IL-3-stimulated adhesion. Our data suggest that cytokines GM-CSF and IL-3 specifically stimulate beta 1 integrin function via an "inside-out" mechanism involving protein kinase activity, while KL stimulates integrin activity through a similar, but initially distinct, pathway via the KIT tyrosine-kinase. Thus, in addition to promoting the survival, proliferation, and development of hemopoietic progenitors, cytokines also regulate adhesive interactions between progenitor cells and the bone marrow microenvironment by modifying the functional states of specific integrins. These data are of importance in understanding the fundamental processes of beta 1 integrin activation and cellular response to mitogenic cytokines as well as on the clinical setting where cytokines induce therapeutic mobilization of hematopoietic progenitors.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1995QV92900021&KeyUID=WOS:A1995QV92900021

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May 1995
16 Reads

Signals from platelet/endothelial cell adhesion molecule enhance the adhesive activity of the very late antigen-4 integrin of human CD34+ hemopoietic progenitor cells.

J Immunol 1994 Nov;153(10):4673-83

Matthew Roberts Laboratory, Hanson Centre for Cancer Research, Adelaide, Australia.

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November 1994
5 Reads
4.922 Impact Factor

Potential adhesion mechanisms for localisation of haemopoietic progenitors to bone marrow stroma

Leuk Lymphoma. 1994 Feb;12(5-6):353-63.

Leukemia & Lymphoma

Haemopoiesis occurs in intimate physical association with the stromal elements of the bone marrow. Current evidence supports the hypothesis that the restriction of primitive haemopoietic progenitor cells (HPC) to the bone marrow involves developmentally regulated adhesive interactions between HPC and the stromal cell microenvironment. This review examines the expression and function of cell adhesion molecules (CAM) on human HPC and marrow stromal cells. These data demonstrate that a broad range of CAMs representing at least three adhesion molecule superfamilies (integrins, selectins, immunoglobulin gene superfamily) participate in these adhesive interactions. We discuss the potential contribution of these various adhesion molecules to homing of HPC to the bone marrow, their retention within the extravascular haemopoietic compartment and their egress into the peripheral circulation. It is likely that each process is mediated not by a single binding event but requires the coordinated participation of multiple receptor-ligand pairs.

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February 1994
17 Reads

Integrin β1- and β3-mediated endothelial cell migration is triggered through distinct signaling mechanisms

J Cell Biol. 1993 Apr;121(1):163-70.

Journal of Cell Biology

Human umbilical vein endothelial cell attachment, spreading and migration on collagen and vitronectin are mediated by integrins alpha 2 beta 1 and alpha v beta 3, respectively, and these events take place in the absence of cytokines, growth factors, or chemoattractants. Cell attachment and spreading on these ligands occur in the absence of extracellular calcium, as does migration on collagen. In contrast, vitronectin-mediated migration is absolutely dependent on the presence of extracellular calcium. Cell contact with immobilized vitronectin or anti-alpha v beta 3 mAbs promotes a measurable rise in [Ca2+]i which requires an extracellular calcium source, whereas collagen, or anti-alpha 2 beta 1 mAbs fail to promote this signaling event. In fact, vitronectin-mediated migration and the rise in intracellular calcium showed the same dose dependence on extracellular calcium. While vitronectin and collagen differ in their ability to induce a calcium influx both ligands or antibodies to their respective integrins promote an equivalent increase in intracellular pH consistent with activation of the Na/H antiporter an event independent of extracellular calcium. These results support two salient conclusions. Firstly, collagen and vitronectin, through their respective integrins, promote distinct intracellular signaling events. Secondly, the alpha v beta 3 specific influx of calcium is not required for cell spreading yet appears to facilitate cellular migration on vitronectin.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1993KU17400016&KeyUID=WOS:A1993KU17400016

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April 1993
16 Reads

Integrin beta 1- and beta 3-mediated endothelial cell migration is triggered through distinct signaling mechanisms

J Cell Biol. 1993 Apr;121(1):163-70.

The Journal of Cell Biology

Human umbilical vein endothelial cell attachment, spreading and migration on collagen and vitronectin are mediated by integrins alpha 2 beta 1 and alpha v beta 3, respectively, and these events take place in the absence of cytokines, growth factors, or chemoattractants. Cell attachment and spreading on these ligands occur in the absence of extracellular calcium, as does migration on collagen. In contrast, vitronectin-mediated migration is absolutely dependent on the presence of extracellular calcium. Cell contact with immobilized vitronectin or anti-alpha v beta 3 mAbs promotes a measurable rise in [Ca2+]i which requires an extracellular calcium source, whereas collagen, or anti-alpha 2 beta 1 mAbs fail to promote this signaling event. In fact, vitronectin-mediated migration and the rise in intracellular calcium showed the same dose dependence on extracellular calcium. While vitronectin and collagen differ in their ability to induce a calcium influx both ligands or antibodies to their respective integrins promote an equivalent increase in intracellular pH consistent with activation of the Na/H antiporter an event independent of extracellular calcium. These results support two salient conclusions. Firstly, collagen and vitronectin, through their respective integrins, promote distinct intracellular signaling events. Secondly, the alpha v beta 3 specific influx of calcium is not required for cell spreading yet appears to facilitate cellular migration on vitronectin.

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April 1993
13 Reads

Requirement of the integrin β3 subunit for carcinoma cell spreading or migration on vitronectin and fibrinogen

J Cell Biol. 1992 Jun;117(5):1101-7.

Journal of Cell Biology

FG human pancreatic carcinoma cells use integrin alpha v beta 5 as their primary vitronectin receptor since they fail to express integrin alpha v beta 3. These cells are unable to form focal contacts, spread, or migrate on vitronectin but readily do so on collagen in a beta 1 integrin-dependent manner. Transfection of FG cells with a cDNA encoding the integrin beta 3 subunit results in the surface expression of a functional integrin alpha v beta 3 heterodimer providing these cells with novel adhesive and biological properties. Specifically, FG cells expressing beta 3 acquire the capacity to attach and spread on vitronectin as well as fibrinogen with beta 3 localization to focal contacts. Moreover, these cells gain the capacity to migrate through a porous membrane in response to either vitronectin or fibrinogen. These results demonstrate that the beta 3 and beta 5 integrin subunits when associated with alpha v, promote distinct cellular responses to a vitronectin extracellular environment.

http://www.scopus.com/inward/record.url?eid=2-s2.0-0026764576&partnerID=MN8TOARS

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June 1992
13 Reads

Purification of the 25-kDa Vibrio cholerae major outer-membrane protein and the molecular cloning of its gene: ompV.

Eur J Biochem. 1985 Apr 15;148(2):385-90.

European Journal of Biochemistry

The 25-kDa peptidoglycan-associated outer-membrane protein and most likely porin of Vibrio cholerae is a major immunogenic species. It has been purified by ion-exchange elution on hydroxyapatite followed by gel filtration on Bio-Gel P150 both in the presence of sodium dodecyl sulfate. This protein, of greater than 90% purity as judged by Western blotting, has been used to raise antibodies in rabbits. The antisera were then used to screen V. cholerae gene banks, constructed in Escherichia coli K12, and this has enabled us to isolate several colonies harbouring the cloned gene. The plasmids in these colonies have been designated pPM451, pPM455 and pPM472. These plasmids have a 5.3 X 10(3)-base BamHI fragment of V. cholerae DNA in common. Restriction endonuclease mapping of these plasmids has been performed and the protein identified both by Western blot analysis and in E. coli K12 minicells. The protein is not efficiently expressed in E. coli K12. It is proposed to use the name ompV to describe the structural gene, present in the cloned DNA, for this V. cholerae outer membrane protein.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1985AGB9200025&KeyUID=WOS:A1985AGB9200025

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April 1985
13 Reads

Molecular cloning using immune sera of a 22-kDal minor outer membrane protein of Vibrio cholerae.

Gene. 1985;34(1):95-103.

Gene

Using antisera prepared against live Vibrio cholerae we have selected several recombinant DNA clones, plasmids pPM440, pPM450 and pPM460, encoding the gene for a 22-kDal V. cholerae peptidoglycan-associated-outer-membrane protein. This is a minor protein in V. cholerae but is expressed in large amounts when the cloned gene is present in Escherichia coli K-12, where it is exposed on the cell surface as judged by ELISA. We have localized the gene within the cloned DNA by transposon mutagenesis and deletion analysis followed by analysis of whole cells and minicells to identify the plasmid-encoded proteins. The DNA region encoding the protein seems to be conserved between El Tor and Classical strains as judged by Southern DNA hybridization.

http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1985AFG9800012&KeyUID=WOS:A1985AFG9800012

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January 1985
19 Reads

Top co-authors

Zee Upton
Zee Upton

Queensland University of Technology

29
Yan Xie
Yan Xie

Zhejiang University

7
Brett G Hollier
Brett G Hollier

Queensland University of Technology

7
Kerry J Manton
Kerry J Manton

Queensland University of Technology

5
Jos Malda
Jos Malda

Utrecht University

5
Abhishek S Kashyap
Abhishek S Kashyap

Institute of Health and Biomedical Innovation

4
Gary K Shooter
Gary K Shooter

Queensland University of Technology

4
Chen Fan
Chen Fan

College of Plant Protection

4
Sean Richards
Sean Richards

University of Tennessee at Chattanooga

4
Karsten Schrobback
Karsten Schrobback

Institute of Health and Biomedical Innovation

3