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Biomedical subjects

Richard Murray

Publications and source records attributed to Richard Murray.

18 recordsLinked to original sources
PubMed2006

Preclinical evaluation of an anti-alpha5beta1 integrin antibody as a novel anti-angiogenic agent.

Integrin alpha5beta1, the principal fibronectin receptor, is an important survival factor, playing a key role in angiogenesis. Angiogenesis is critical for tumor growth, and anti-angiogenic therapies have met clinical success. To validate the therapeutic potential of an anti-alpha5beta1 strategy, we generated volociximab (M200) a chimeric human IgG4 version of the alpha5beta1 function-blocking murine antibody IIA1; and F200, the Fab derivative. Volociximab, F200 and IIA1 showed similar activity by ELISA (EC50= 0.2nM), Biacore (Kd= 0.1-0.4nM) and inhibition of fibronectin binding (IC50= 2-3nM). The inhibitory potential of alpha5beta1 antibodies was compared to HuMV833, an anti-VEGF antibody. Both volociximab and HuMV833 inhibited HUVEC proliferation (IC50 of volociximab = 0.2-0.5nM; IC50 of HuMV833 = 45nM). However, IIA1, volociximab and F200 were also potent inhibitors of an in vitro model of angiogenesis (HUVEC tube formation assay), unlike HuMV833. Additionally, volociximab inhibited in vitro tube formation induced by VEGF and/or bFGF, suggesting a mechanism of action independent of growth factor stimulus. In fact, inhibition of alpha5beta1 function by volociximab induced apoptosis of actively proliferating, but not resting, endothelial cells. Volociximab does not cross-react with rodent alpha5beta1, therefore in vivo validation of an anti-alpha5beta1 approach was conducted in a cynomolgus model of choroidal revascularization. Volociximab and F200 were potent inhibitors of neovessel formation in this model. These data demonstrate that volociximab has therapeutic potential in diseases in which new vessel formation is a component of the pathology.

Angiogenesis Inhibitors↗
PubMed2005

Distinctive and indispensable roles of PU.1 in maintenance of hematopoietic stem cells and their differentiation.

The PU.1 transcription factor is a key regulator of hematopoietic development, but its role at each hematopoietic stage remains unclear. In particular, the expression of PU.1 in hematopoietic stem cells (HSCs) could simply represent "priming" of genes related to downstream myelolymphoid lineages. By using a conditional PU.1 knock-out model, we here show that HSCs express PU.1, and its constitutive expression is necessary for maintenance of the HSC pool in the bone marrow. Bone marrow HSCs disrupted with PU.1 in situ could not maintain hematopoiesis and were outcompeted by normal HSCs. PU.1-deficient HSCs also failed to generate the earliest myeloid and lymphoid progenitors. PU.1 disruption in granulocyte/monocyte-committed progenitors blocked their maturation but not proliferation, resulting in myeloblast colony formation. PU.1 disruption in common lymphoid progenitors, however, did not prevent their B-cell maturation. In vivo disruption of PU.1 in mature B cells by the CD19-Cre locus did not affect B-cell maturation, and PU.1-deficient mature B cells displayed normal proliferation in response to mitogenic signals including the cross-linking of surface immunoglobulin M (IgM). Thus, PU.1 plays indispensable and distinct roles in hematopoietic development through supporting HSC self-renewal as well as commitment and maturation of myeloid and lymphoid lineages.

Animals↗
PubMed2005

Rapid access of antibodies to alpha5beta1 integrin overexpressed on the luminal surface of tumor blood vessels.

Integrin alpha(5)beta(1) is overexpressed on endothelial cells of tumor vessels and is uniformly and rapidly accessible to antibodies in the bloodstream. Here, we determined whether antibodies rapidly gain access to integrin overexpressed on the abluminal (basolateral) surface of endothelial cells through vascular leakiness or whether the rapid accessibility results instead because the integrin is overexpressed on the luminal (apical) surface of endothelial cells due to loss of cell polarity. Using tumors in RIP-Tag2 transgenic mice as a model, we first compared the binding pattern of intravascular anti-alpha(5)beta(1) integrin antibody with the leakage pattern of nonspecific IgG. The distributions did not match: anti-alpha(5)beta(1) integrin antibody uniformly labeled the tumor vasculature, but IgG was located in patchy sites of leakage. We next injected an antibody to fibrinogen/fibrin, which resulted in patchy labeling of tumors that matched the leakage of IgG and the overall distribution of fibrin in tumors. Similarly, injected antibodies to the basement membrane protein fibronectin, a ligand of alpha(5)beta(1) integrin, or type IV collagen produced patchy sites of leakage instead of uniform labeling of vascular basement membrane. Differences in the kinetics of labeling, which for alpha(5)beta(1) integrin antibody was near maximal by 10 minutes but for the other antibodies gradually increased over 6 hours, indicated differences in accessibility of their respective targets. Isosurface rendering of confocal microscopic images was consistent with antibody binding to alpha(5)beta(1) integrin on the luminal surface of endothelial cells. Together, these findings indicate that the rapid accessibility of alpha(5)beta(1) integrin in RIP-Tag2 tumors results from overexpression of the integrin on the luminal surface of tumor vessels.

Adenoma, Islet Cell↗
PubMed2005

Uniform overexpression and rapid accessibility of alpha5beta1 integrin on blood vessels in tumors.

Integrin alpha5beta1 is among the proteins overexpressed on tumor vessels and is a potential target for diagnostics and therapeutics. Here, we mapped the distribution of alpha5beta1 integrin in three murine tumor models and identified sites of expression that are rapidly accessible to intravascular antibodies. When examined by conventional immunohistochemistry, alpha5beta1 integrin expression was strong on most blood vessels in RIP-Tag2 transgenic mouse tumors, adenomatous polyposis coli (apc) mouse adenomas, and implanted MCa-IV mammary carcinomas. Expression increased during malignant progression in RIP-Tag2 mice. However, immunoreactivity was also strong in normal pancreatic ducts, intestinal smooth muscle, and several other sites. To determine which sites of expression were rapidly accessible from the bloodstream, we intravenously injected anti-alpha5beta1 integrin antibody and 10 minutes to 24 hours later examined the amount and distribution of labeling. The injected antibody strongly labeled tumor vessels at all time points but did not label most normal blood vessels or gain access to pancreatic ducts or intestinal smooth muscle. Intense vascular labeling by anti-alpha5beta1 integrin antibody co-localized with the uniform CD31 immunoreactivity of tumor vessels and contrasted sharply with the patchy accumulation of nonspecific IgG at sites of leakage. This strategy of injecting antibodies revealed the uniform overexpression and rapid accessibility of alpha5beta1 integrin on tumor vessels and may prove useful in assessing other potential therapeutic targets in cancer.

Animals↗
PubMed2005

'We are not just participants--we are in charge': the NACCHO ear trial and the process for Aboriginal community-controlled health research.

OBJECTIVE: Methodological criteria that characterise ethically sound community-based studies are often described in overviews but are rarely documented in clinical studies. Research investigating the health of Aboriginal Australians is often small-scale, descriptive and largely driven by non-Indigenous people. The 'community-controlled' model of research relating to Aboriginal peoples health is a form of 'participatory' research that shifts the balance of control towards those being researched. This paper describes the methodological issues and principles that underpin community-controlled health research; their practical application; and encourages their adoption in research involving Indigenous populations. DESIGN: Descriptive report of the methods used to conduct the landmark Aboriginal community-controlled multi-centre double-blind randomised controlled clinical ear trial investigating ototopical treatments for chronic suppurative otitis media. RESULTS: The characteristics of the community-controlled research model are illustrated under the headings of: setting the research agenda; research project planning and approval; conduct of research; and analysis, dissemination and application of findings. CONCLUSION: The 22 methodological elements which defined the community-controlled design of the ear trial may assist community groups, external research bodies and funding agencies to improve the acceptability, quality and scope of research involving Indigenous peoples. Aboriginal community-controlled organisations are well placed to lead research, which can be interventional and of a high scientific standard without compromising the values and principles of those being researched. With over 120 Aboriginal community-controlled health services (ACCHSs) across Australia, the potential exists for these services to engage in multi-centre research to realise solutions to health problems faced by Indigenous Australians.

Anti-Infective Agents↗
PubMed2004

Bring me home: renal dialysis in the Kimberley.

The incidence of end-stage renal failure (ESRF) in the Kimberley region at the top end of Western Australia far exceeds known national rates and trend analysis demonstrates a close parallel to what is occurring in the Northern Territory. Dialysis prevalence in the Kimberley has nearly tripled in the last decade and has increased at a much faster rate than the rest of Western Australia. Almost all of these people with ESRF are Aboriginal Australians living in remote communities. In January 2004, the Western Australia Country Health Service and Kimberley Aboriginal Medical Services' Council, under the auspices of the Kimberley Aboriginal Health Planning Forum, embarked upon a review of renal disease in the Kimberley funded by the Western Australia Department of Health. The main purpose of the review was to identify the scope of the problem and make projections upon which to base programme and service development over the next 10 years. This paper outlines the findings of the Review of Renal Disease in the Kimberley and presents, for the first time, regional data analysis and comparisons. In addition, future projections on the impact of ESRF and recommendations for improving current service delivery are discussed. Given the challenges of remoteness and individuals' desire to return home, this review recommends development of locally-based expertise capable of providing training and support to patients and their families, reinvigoration of community-based dialysis modalities, and the initiation of planning for a second satellite service in the Kimberley.

Ambulatory Care Facilities↗
PubMed2004

Preclinical validation of anti-TMEFF2-auristatin E-conjugated antibodies in the treatment of prostate cancer.

Current treatments for advanced stage, hormone-resistant prostate cancer are largely ineffective, leading to high patient mortality and morbidity. To fulfill this unmet medical need, we used global gene expression profiling to identify new potential antibody-drug conjugate (ADC) targets that showed maximal prostate cancer-specific expression. TMEFF2, a gene encoding a plasma membrane protein with two follistatin-like domains and one epidermal growth factor-like domain, had limited normal tissue distribution and was highly overexpressed in prostate cancer. Immunohistochemistry analysis using a specific monoclonal antibody (mAb) to human TMEFF2 showed significant protein expression in 74% of primary prostate cancers and 42% of metastatic lesions from lymph nodes and bone that represented both hormone-naïve and hormone-resistant disease. To evaluate anti-TMEFF2 mAbs as potential ADCs, one mAb was conjugated to the cytotoxic agent auristatin E via a cathepsin B-sensitive valine-citrulline linker. This ADC, Pr1-vcMMAE, was used to treat male severe combined immunodeficient mice bearing xenografted LNCaP and CWR22 prostate cancers expressing TMEFF2. Doses of 3 to 10 mg/kg of this specific ADC resulted in significant and sustained tumor growth inhibition, whereas an isotype control ADC had no significant effect. Similar efficacy and specificity was shown with huPr1-vcMMAE, a humanized anti-TMEFF2 ADC. No overt in vivo toxicity was observed with either murine or human ADC, despite significant cross-reactivity of anti-TMEFF2 mAb with the murine TMEFF2 protein, implying minimal toxicity to other body tissues. These data support the further evaluation and clinical testing of huPr1-vcMMAE as a novel therapeutic for the treatment of metastatic and hormone-resistant prostate cancer.

Amino Acid Sequence↗
PubMed2003

E-selectin up-regulation allows for targeted drug delivery in prostate cancer.

We have used the Eos Hu03 GeneChip array, which represents over 92% of the transcribed human genome, to measure gene expression in a panel of normal and diseased human tissues. This analysis revealed that E-selectin mRNA is selectively overexpressed in prostate cancer epithelium, a finding that correlated strongly with E-selectin protein expression as assessed by immunohistochemistry. Antibodies against E-selectin that blocked function failed to impede cancer cell growth, suggesting that overexpression of E-selectin was not essential for cell growth. However, a novel auristatin E-based antibody drug conjugate (ADC), E-selectin antibody valine-citrulline monomethyl-auristatin E, was a potent and selective agent against E-selectin-expressing cancer cell lines in vitro, with the degree of cytotoxicity varying with surface antigen density. Interestingly, sensitivity to the ADC differed among cell lines from different tissues expressing similar amounts of E-selectin and was found to correlate with sensitivity to free auristatin E. Furthermore, E-selectin-expressing tumors grown as xenografts in severe combined immunodeficient mice were responsive to treatment with E-selectin antibody valine-citrulline monomethyl-auristatin E in vivo, with more than 85% inhibition of tumor growth observed in treated mice. These findings demonstrate that an E-selectin-targeting ADC has potential as a prostate cancer therapy and validates a genomics-based paradigm for the identification of cancer-specific antigens suitable for targeted therapy.

Animals↗
PubMed2003

Matrilysin-dependent elastolysis by human macrophages.

Human macrophages found in juxtaposition to fragmented elastin in vivo express the elastolytic matrix metalloproteinases (MMPs) progelatinase B, prometalloelastase, and promatrilysin. Though MMPs can degrade a range of extracellular matrix components, increasing evidence suggests that preferred targets in vivo include nonmatrix substrates such as chemokines and growth factors. Hence, the means by which MMPs participate in elastin turnover remain undefined as does the identity of the elastolysins. Herein, human macrophage cultures have been established that express a complement of elastolytic proteinases similar, if not identical, to that found in vivo. Under plasminogen-free conditions, macrophages preferentially use metalloelastase to mediate elastolysis via a process that deposits active enzyme on elastin surfaces. By contrast, in the presence of plasminogen, human macrophages up-regulate proteolysis 10-fold by processing promatrilysin to an active elastolysin via a urokinase-type plasminogen activator-dependent pathway. Matrilysin-deficient human macrophages fail to mediate an elastolytic response despite the continued expression of gelatinase B and metalloelastase. Thus, acting in concert with cosecreted cysteine proteinases whose activities are constrained to sites of macrophage-elastin contact (Punturieri, A., S. Filippov, E. Allen, I. Caras, R. Murray, V. Reddy, and S.J. Weiss. 2000. J. Exp. Med. 192:789-799), matrilysin confers macrophages with their most potent MMP-dependent elastolytic system.

Animals↗
PubMed2003

Effectiveness of ototopical antibiotics for chronic suppurative otitis media in Aboriginal children: a community-based, multicentre, double-blind randomised controlled trial.

OBJECTIVES: To compare the effectiveness of ototopical ciprofloxacin (0.3%; CIP) with framycetin (0.5%), gramicidin, dexamethasone (FGD) eardrops (5 drops twice daily for 9 days) together with povidone-iodine (0.5%) ear cleaning as treatments for chronic suppurative otitis media (CSOM) in Aboriginal children. DESIGN AND PARTICIPANTS: Aboriginal community-controlled, community-based, multicentre, double-blind, randomised controlled trial in eight Aboriginal Community Controlled Health Services across northern Australia, involving 147 Aboriginal children with CSOM. MAIN OUTCOME MEASURES: Resolution of otorrhoea (clinical cure), proportion of children with healed perforated tympanic membrane (TM) and improved hearing, 10-21 days after starting treatment. RESULTS: 111 children aged 1-14 years (CIP, 55; FGD, 56) completed treatment. CSOM cures occurred in 64% (CIP, 76.4%; FGD, 51.8%), with a significantly higher rate in the ciprofloxacin group (P = 0.009, absolute difference of 24.6% [95% CI, 15.8%-33.4%]). TM perforation size and the level of hearing impairment did not change. Pseudomonas aeruginosa was the most common bacterial pathogen (in 47.6%), while respiratory pathogens were rare (in 5.7%). CONCLUSIONS: Twice-daily ear cleaning and topical ciprofloxacin is effective at community-level in achieving cure for CSOM. Healthcare providers to Aboriginal children with CSOM should be given special access to provide ototopical ciprofloxacin as first-line treatment.

Administration, Topical↗
PubMed2003

Pelvic and femoral contributions to bilateral hip flexion by subjects suspended from a bar.

OBJECTIVE: To quantify the contribution of the pelvis and femur to active bilateral hip flexion conducted while subjects are suspended by their hands from a bar. DESIGN: Descriptive and experimental. BACKGROUND: Voluntary hip flexion while in a suspended position is used in abdominal strengthening regimens and is required for certain athletic activities. The degree to which pelvic rotation contributes to this maneuver has not been established. METHODS: Pelvic and femoral motions were documented in 14 subjects who performed bilateral hip flexion while they hung by their hands from a bar. A supporting board as well as the trunk, pelvis and thigh were marked with reflective spheres; motion of the pelvis and thigh relative to the board was captured by video analysis. Ratios of pelvic to femoral motion were calculated and the influence of hamstring length (<78 degrees vs >78 degrees of straight leg raising) and knee position (flexed vs extended) on the ratio was determined. RESULTS: The mean pelvifemoral ratio ranged from 0.131 to 0.355, depending on hamstring length and knee position. Pelvic rotation therefore contributed a mean 13.1-35.5% of the observed hip flexion. A 2 x 2 mixed-model analysis of variance showed that the ratio was influenced significantly by each of these two independent variables. The largest pelvic contribution occurred during hip flexion with the knee in the extended position among subjects with shorter hamstrings. CONCLUSIONS: Pelvic motion is an integral part of hip flexion conducted while subjects are suspended their hands from a bar. The pelvic contribution depends on knee position and hamstring length. RELEVANCE: During suspended activities involving hip flexion (e.g. gymnastics), pelvic rotation plays an integral role throughout the range. Inherent or imposed differences in hamstring length can alter the contribution of the pelvis to the motion. Hip flexion, therefore, might be influenced by conditions affecting the ability of the pelvis to rotate (e.g. spinal fusion), or the femur to move on the pelvis (e.g. degenerative joint disease), or be altered by hamstring tension.

Adult↗
PubMed2002

Pelvifemoral rhythm during unilateral hip flexion in standing.

OBJECTIVE: To quantify pelvifemoral rhythm during unilateral hip flexion in standing subjects, under different degrees of resistance. DESIGN: Descriptive and correlational. BACKGROUND: Pelvic rotation contributes to the change in hip flexion angle while individuals are supine. Degree of contribution in standing has not been described. METHODS: Pelvic and femoral motions, relative to vertical, were documented while 14 subjects performed three trials of standing unilateral hip flexion, both with and without a 4.53 kg ankle weight. Pelvic and thigh segments were marked with reflective spheres, and motion was captured by video analysis. RESULTS: Pelvic rotation contributed 18.1% of the change in hip flexion angle. Pelvic rotation occurred throughout the movement. Neither presence of external resistance nor direction of movement significantly changed this contribution. CONCLUSIONS: A strong relationship exists between pelvic rotation and hip flexion in standing subjects. RELEVANCE: Hip flexion, while standing, is a common element of many functional activities. Knowledge of the pelvic contribution increases our understanding of hip and lumbar spine motion during standing activities.

Adult↗
PubMed2002

Increased vulnerability of dopaminergic neurons in MPTP-lesioned interleukin-6 deficient mice.

To test the hypothesis that neuroinflammation contributes to dopaminergic neuron death in the MPTP-lesioned mouse, we compared nigrostriatal degeneration in interleukin (IL)-6 (+/+) with IL-6 (-/-) mice. In the absence of IL-6, a single injection of MPTP (30 mg/kg) resulted in significantly greater striatal dopamine depletion than that measured in IL-6 (+/+) mice. The observed dopamine depletion was MPTP dose dependent. This loss of striatal dopamine and a significantly greater loss of TH+ cells in the substantia nigra pars compacta in IL-6 (-/-) mice as compared with control IL-6 (+/+) mice, suggest that IL-6 is neuroprotective in the MPTP-lesioned nigrostriatal system. Co-localization experiments identified striatal astrocytes as the source of IL-6 in IL-6 (+/+) mice at 1 and 7 days postinjection of MPTP. The increased sensitivity of dopaminergic neurons to neurotoxicant in the absence of IL-6, is compatible with a neuroprotective activity of IL-6 in the injured nigrostriatal system.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2002

Kinematics of the double-leg-lowering test for abdominal muscle strength.

STUDY DESIGN: Prospective descriptive study. OBJECTIVE: To investigate the kinematics of the double-leg-lowering (DLL) test of abdominal muscle strength. BACKGROUND: Adequate strength of the abdominal muscles is necessary for many household, occupational, and sports activities. Therapists, therefore, need valid measures of abdominal muscle strength. METHODS AND MEASURES: A convenience sample of 17 subjects (7 women, 10 men) was tested. Using reflective spheres to identify specific body segments, subjects were videotaped while performing DLL under 2 conditions: attempting (controlled) prevention of anterior pelvic tilting versus not attempting (uncontrolled) prevention of anterior pelvic tilting. Videotape was analyzed using the PEAK 5 2-dimensional system. RESULTS: The pelvis tilted anteriorly by the time the extremities were lowered a mean 3.6 degrees, regardless of condition. No significant difference in anterior pelvic tilting was associated with the 2 DLL conditions (F = 2.95, P = 0.105) but pelvic tilting did increase significantly as the lower extremities were lowered from vertical (F = 98.41, P < 0.001). CONCLUSIONS: There appears to be a natural tendency for the pelvis to tilt anteriorly from very early in the DLL maneuver. As healthy young subjects do not appear able to prevent the tilting, the scoring system associated with the DLL test should be questioned.

Abdominal Muscles↗
PubMedDate not supplied

Molecular signals regulating proliferation of stem and progenitor cells in mouse olfactory epithelium.

To understand how signaling molecules regulate the generation of neurons from proliferating stem cells and neuronal progenitors in the developing and regenerating nervous system, we have studied neurogenesis in a model neurogenic epithelium, the olfactory epithelium (OE) of the mouse. Our studies have employed a candidate approach to test signaling molecules of potential importance in regulating neurogenesis and have utilized methods that include tissue culture, in situ hybridization and mouse genetics. Using these approaches, we have identified three distinct stages of stem and transit amplifying progenitor cells in the differentiation pathway of olfactory receptor neurons (ORNs) and have identified mechanisms by which the development of each of these progenitor cell types is regulated by signals produced both within the OE itself and by its underlying stroma. Our results indicate that regulation of olfactory neurogenesis is critically dependent on multiple signaling molecules from two different polypeptide growth factor superfamilies, the fibroblast growth factors and the transforming growth factor beta (TGF-beta) group. In addition, they indicate that these signaling molecules interact in at least two important ways: first, opposing signals converge on cells at specific developmental stages in the ORN pathway to regulate proliferation and differentiation; and second, these signaling molecules--particularly the TGF-betas and their antagonists--play key roles in feedback loops that regulate the size of progenitor cell pools and thereby neuron number, during development and regeneration.

Animals↗