ORCID Profile
0000-0002-9866-4694
Current Organisations
University of Technology Sydney
,
University of New South Wales
,
Swinburne University of Technology
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Publisher: S. Karger AG
Date: 2003
DOI: 10.1159/000069006
Abstract: i Background: /i i Pseudomonas aeruginosa /i infection is one of the most destructive diseases of the eye. The host response to this infection is critical to the outcome. Interleukin-6 (IL-6) is implicated in this response however, the mechanisms by which IL-6 contributes to the host defences in corneal infection remain unclear. Using IL-6–/– mice, we have explored the role of IL-6 in i P. aeruginosa /i keratitis. i Methods: /i The eyes of IL-6 gene knockout and wild-type mice were challenged topically with i P. aeruginosa /i and examined on days 1–7. Keratitis was examined clinically and histologically. Cytokine, chemokine and complement 3 levels were determined by ELISA and ICAM-1 by immunohistochemistry. i Results: /i Clinically, the IL-6–/– mice showed more severe disease than wild-type mice and this was supported by the histological findings. More than 2-fold higher bacterial load was detected in the eyes of the IL-6–/– mice than in those of the wild-type mice. Neutrophil infiltration to the central cornea of the IL-6–/– mice failed to occur in response to infection, although a greater number of neutrophils were present in the whole eye. This may in part be due to the reduced expression of the adhesion molecule ICAM-1 in the cornea, but does not appear to stem from insufficient production of chemokines or complement 3. i Conclusions: /i Our findings indicate that IL-6 is critical to the host defence of the cornea during i P. aeruginosa /i infection. Pharmacological manipulation of the IL-6 response may represent a rational strategy for new interventions.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 21-03-2012
DOI: 10.1167/IOVS.11-8365
Abstract: Matrix metalloproteinases (MMPs) are degrading enzymes which maintain and remodel tissue architecture. Upregulation of MMP-9 has been associated with corneal erosions and ulceration. As these conditions are often exacerbated on waking, suggesting that degrading activity is upregulated overnight, this study set out to determine the diurnal variation of MMP-9, Tissue Inhibitor of Metalloproteinase (TIMP)-1, and Neutrophil Gelatinase-Associated Lipocalin (NGAL). Flush tears were collected from 46 healthy, non-contact lens wearers at midday, before sleep, and immediately on waking. Total protein content (TPC) was measured using the bicinchoninic acid method, and MMP-9, TIMP-1, and NGAL concentrations were measured using sandwich enzyme-linked immunoassay. Statistical analysis was performed using repeated measures analysis of variance. TPC was 3.4 ± 1.5 mg/mL, 5.0 ± 3.7 mg/mL and 15.5 ± 8.4 mg/mL for midday, before sleep, and on waking respectively, the latter being significantly greater than the other two (P < 0.001). MMP-9 concentrations at the corresponding time points were 9.8 ± 14.3 ng/mL, 8.5 ± 11.7 ng/mL, and 2000.7 ± 1950.7 ng/mL. Again, the value on waking was significantly greater than the previous two visits (P < 0.001). TIMP-1 concentrations exceeded those of MMP-9 at midday but the ratio of the two reversed on awakening. Concentrations of MMP-9 are negligible during the day and completely inhibited by TIMP-1. On awakening, MMP-9 increases 200-fold, an increase that is not completely inhibited by TIMP-1. This diurnal change, along with the presence of NGAL which protects MMP-9 from degradation, suggests that the closed eye is an environment conducive to extracellular matrix remodeling.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 11-2006
DOI: 10.1167/IOVS.06-0340
Abstract: To determine whether interleukin-6 (IL-6) plays a protective role in Staphylococcus aureus keratitis in a gene knockout (gko) mouse model and to determine whether IL-6 may be used as a therapy to modulate host responses and control bacterial infection, thereby reducing scarring. The eyes of IL-6 gko mice and wild-type mice were challenged topically with S. aureus and examined at 24 hours after infection. Keratitis was examined clinically and histologically. Bacterial and polymorphonuclear leukocytes (PMNs) were enumerated, and cytokine and chemokine levels were determined by ELISA. Exogenous IL-6 was administered to both IL-6 gko and wild-type mice, and clinical parameters were determined. IL-6 gko mice showed more severe disease, with increased bacterial counts and PMNs, than did wild-type mice. Changes in levels of chemokines and cytokines were also observed. Administration of exogenous IL-6 resulted in an improved outcome in IL-6 gko mice, with a threefold reduction in bacterial load. The data suggest an important regulatory role for IL-6 in modulating excessive inflammatory responses and in controlling bacterial proliferation. IL-6 may play a role in the priming and activation of neutrophils. It could represent a broad-spectrum therapy to improve outcomes in patients who have these potentially blinding infections.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2007
Publisher: Oxford University Press (OUP)
Date: 12-2008
DOI: 10.1111/J.1365-2672.2008.03942.X
Abstract: To develop an antimicrobial peptide with broad spectrum activity against bacteria implicated in biomaterial infection of low toxicity to mammalian cells and retaining its antimicrobial activity when covalently bound to a biomaterial surface. A synthetic peptide (melimine) was produced by combining portions of the antimicrobial cationic peptides mellitin and protamine. In contrast to the parent peptide melittin which lysed sheep red blood cells at >10 microg ml(-1), melimine lysed sheep red blood cells only at concentrations >2500 microg ml(-1), well above bactericidal concentrations. Additionally, melimine was found to be stable to heat sterilization. Evaluation by electron microscopy showed that exposure of both Pseudomonas aeruginosa and Staphylococcus aureus to melimine at the minimal inhibitory concentration (MIC) produced changes in the structure of the bacterial membranes. Further, repeated passage of these bacteria in sub-MIC concentrations of melimine did not result in an increase in the MIC. Melimine was tested for its ability to reduce bacterial adhesion to contact lenses when adsorbed or covalently attached. Approximately 80% reduction in viable bacteria was seen against both P. aeruginosa and S. aureus for 500 microg per lens adsorbed melimine. Covalently linked melimine (18 +/- 4 microg per lens) showed >70% reduction of these bacteria to the lens. We have designed and tested a synthetic peptide melimine incorporating active regions of protamine and mellitin which may represent a good candidate for development as an antimicrobial coating for biomaterials. Infection associated with the use of biomaterials remains a major barrier to the long-term use of medical devices. The antimicrobial peptide melimine is an excellent candidate for development as an antimicrobial coating for such devices.
Publisher: Oxford University Press (OUP)
Date: 06-10-2006
DOI: 10.1189/JLB.0506344
Abstract: Pseudomonas is one of the leading causes of contact lens-related microbial keratitis. Despite the use of antibiotics, the host inflammatory response continues to cause damage to the cornea, which may lead to blindness. CXCR2-binding chemokines have been implicated in the pathogenesis of Pseudomonas keratitis, and the exact role of this receptor remains to be elucidated. Corneas of CXCR2 knockout and wild-type mice (Cmkar 2−/− and Cmkar 2+/+) were scratched, and 2 × 106 CFU/mL Pseudomonas 6294 or 6206 was added to corneas. Twenty-four hours postinfection, mice were killed, and eyes were harvested for enumeration of bacteria, myeloperoxidase (MPO) levels, and inflammatory mediators. Cmkar 2−/− had 20- to 100-fold more bacteria than Cmkar 2+/+ mice. There were no differences in MPO levels between gene knockout and Cmkar 2+/+ mice. Histology revealed PMN were restricted to the limbal area. Levels of CXCR2 chemokines (keratinocyte-derived chemokine and MIP-2) were elevated significantly in gene knockout mice. A lack of CXCR2 leads to an inability to control bacterial numbers as a result of the inability of PMN to reach the site of infection in the avascular cornea. These results imply that CXCR2 is critical to the extravasation of neutrophils into the avascular cornea.
Publisher: S. Karger AG
Date: 16-12-2009
DOI: 10.1159/000265530
Abstract: i Background: /i Propolis is a honeybee product that has been used in traditional medicine for antioxidant, immune-stimulating, anti-inflammatory and anti-cancer effects. Here, the potential of the topical application of a crude ethanolic extract of Sydney propolis to protect against UV-radiation-induced impairments associated with an increased risk of photocarcinogenesis has been tested in the hairless mouse. i Methods: /i Solutions providing between 10 and 200 mg/kg propolis were applied to the skin following UV irradiation. The inflammation from exposure to UV (290–400 nm) was quantitated by measurement of increased skinfold thickness lipid peroxidation was assayed by the induction of thiobarbituric acid reactive species in the skin immune function was measured by the contact hypersensitivity (CHS) reaction and supported by the changes in epidermal cytokine expression. i Results: /i Propolis protected significantly and dose-dependently against both sunburn oedema and the suppression of CHS, and (at 100 mg/kg) against lipid peroxidation. The overexpression of IL-10 and the depletion of IL-12 characteristic of photoimmune suppression were markedly reduced by propolis. Further, the upregulation of IL-6 was decreased, and the associated induction of haem oxygenase was shown to play a role in propolis skin protection. i Conclusions: /i Sydney propolis was able to effectively reduce cutaneous inflammation, immunosuppression and lipid peroxidation induced by UV exposure. It is concluded that Sydney propolis might have strong beneficial protective effects against photodamage and skin cancer development in humans.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC02231B
Abstract: Studying the neuroanatomy of the mouse brain using imaging mass spectrometry and chemometric analysis.
Publisher: American Society for Microbiology
Date: 02-2012
DOI: 10.1128/AAC.05814-11
Abstract: Antibiotic-resistant Staphylococcus aureus is of great concern, as it causes a wide range of life-threatening infections. The current study demonstrates that dihydropyrrolone (DHP)-coated polyacrylamide substrates are effective in reducing the number of culturable clinical isolates of S. aureus in vitro in a dose-dependent manner and are able to reduce the pathogenic potential of staphylococcal infection in a subcutaneous infection model. Covalently bound DHPs therefore show great potential for use as an antimicrobial strategy in device-related applications.
Publisher: Elsevier BV
Date: 11-1993
DOI: 10.1016/0020-711X(93)90511-C
Abstract: 1. Spectrin extracted from ovine erythrocyte membranes at low temperature shows association behaviour similar to that reported for human and bovine erythrocytes. 2. The spectrin tetramer is the predominant oligomer, the dimer is well represented, and smaller amounts of hexamer and higher oligomers are present. 3. The estimates of parameters describing the self-association of purified ovine spectrin studied by sedimentation equilibrium analysis were found to be indistinguishable from those obtained for human spectrin under the same conditions, within the precision of the measurements. 4. The data suggest that the cooperative isodesmic model may be general for spectrin, and not a peculiarity of the human.
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.FORSCIINT.2017.02.013
Abstract: This article describes the development of a horizontal stabbing machine with an interchangeable knife holder to simulate stab events. The machine consists of a motorised arm with a pneumatic system designed to deliver 60 unique stabbing positions. The mechanics were robust and the positioning system highly reproducible with standard deviations of less than 1.0mm in the x-axis and 2.3mm in the y-axis for a given stab position. The force of the instrument may be varied by the operator to a maximum of approximately 221N. The suitability of the instrument for simulating stab events was evaluated by measuring the severance length and textile damage from stab delivered from four different knives and nine penetrating angles.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2007
Publisher: Wiley
Date: 02-2000
DOI: 10.1046/J.1440-1711.2000.00860.X
Abstract: Pseudomonas aeruginosa can cause ulcerative bacterial keratitis. A feature of keratitis is the rapid infiltration of the avascular corneal stroma by neutrophils. KC is a potent neutrophil chemokine. The present study used a mouse model of ocular infection to assess the relationship between KC and inflammation in the cornea in response to challenge with a strain of P. aeruginosa causing keratitis. Low levels of KC mRNA and protein were detected by in situ hybridization and ELISA, respectively, in unchallenged corneas. Dramatically increased numbers of KC mRNA+ cells were present in P. aeruginosa strain 6294-challenged corneas. Expression of KC mRNA was found to be up-regulated in the corneal epithelium in response to wounding alone. The KC mRNA+ cells were located in the epithelium and corresponding to infiltrating neutrophils cells in the stroma. Quantification of KC protein at different time points showed peak levels at 8 h of bacterial challenge. These results suggest that KC may be involved with the regulation of leucocyte infiltration early during bacterial keratitis.
Publisher: Wiley
Date: 19-06-2007
Abstract: While the role of CC chemokines in mononuclear cell trafficking and activation has been well studied, the functional role of CC chemokines in the regulation of polymorphonuclear neutrophil (PMN) recruitment in vivo has not been widely examined. Bacterial infection of the cornea (keratitis) is a relatively common, sometimes sight-threatening disease, which features acute inflammation with ulceration and PMN infiltration. Here, we demonstrate a critical role for the chemokines, CCL2 and CCL3, in the Pseudomonas aeruginosa-induced model of corneal infection in BALB/c mice. Treatment of mice with anti-CCL2 or anti-CCL3 antibodies resulted in a significant reduction in severity of corneal damage and PMN infiltration at 1 and 7 days after infection compared to control antibody-treated eyes, but did not significantly alter the rate of bacterial clearance from the cornea. Our findings provide strong evidence that CCL2 and CCL3 are critical regulators of PMN recruitment, and may lead to therapeutic strategies via targeting of the CC chemokines, CCL2 and CCL3, in the management of P. aeruginosa keratitis.
Publisher: American Society for Microbiology
Date: 03-2003
DOI: 10.1128/IAI.71.3.1328-1336.2003
Abstract: Pseudomonas aeruginosa keratitis is one of the most destructive diseases of the cornea. The host response to this infection is critical to the outcome. The cytokine interleukin-10 (IL-10) is thought to play an important role in modulating excessive inflammation and antimicrobial defenses. We have found that in IL-10 −/− mice there is a significant decrease in bacterial load in corneas at 7 days postchallenge with P. aeruginosa . This decrease was accompanied by a reduction in neutrophil numbers in the cornea and changes in cytokine levels compared to those of wild-type mice. A characteristic increase in neovascularization in the cornea was found in the IL-10 −/− mice. This increased angiogenesis correlated with an increased expression of KC, whereas the kinetics of macrophage inflammatory peptide 2 expression correlated with neutrophil numbers. This finding suggests that KC may play a role in corneal angiogenesis. The source of IL-10 in mouse corneas was identified as a subpopulation of infiltrating cells and keratocytes. This study demonstrates that IL-10 plays an important role in regulating the balance of inflammatory mediators during P. aeruginosa infection of the cornea.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.BIOMATERIALS.2013.11.072
Abstract: Device-related infection remains a major barrier to the use of biomaterial implants as life-saving devices. This study aims to examine the effectiveness and mechanism of action of surface attached dihydropyrrolones (DHPs), a quorum sensing (QS) inhibitor, against bacterial colonization. DHPs were covalently attached on glass surfaces via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) click reaction. The covalent attachment of DHP surfaces was confirmed by X-ray photoelectron spectroscopy (XPS) and contact angle measurements, and the antimicrobial efficacy of the DHP coatings was assessed by confocal laser scanning microscopy (CLSM) and image analysis. The results demonstrated that covalently bound DHP compounds are effective in reducing the adhesion by up to 97% (p < 0.05) for both Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, using the green fluorescent protein (Gfp)-based reporter technology, it is demonstrated that surface attached DHPs were able to repress the expression of a lasB-gfp reporter fusion of P. aeruginosa by 72% (p < 0.001) without affecting cell viability. This demonstrates the ability of the covalently bound QS inhibitor to inhibit QS and suggests the existence of a membrane-based pathway(s) for QS inhibition. Hence, strategies based on incorporation of QS inhibitors such as DHPs represent a potential approach for prevention of device-related infections.
Publisher: Oxford University Press (OUP)
Date: 07-04-2010
DOI: 10.1093/JAC/DKQ106
Abstract: The objectives of this study were to determine whether a synergistic effect could be obtained in vitro between bovine lactoferricin (B-LFcin) and antibiotics against Pseudomonas aeruginosa and Staphylococcus aureus isolates from ocular infections, and to evaluate the use of B-LFcin as an adjunct to the antibiotic treatment of corneal infection in vivo. Chequerboard and time-kill assays were performed to investigate the combined effects of B-LFcin and conventional antibiotics, including ciprofloxacin, ceftazidime and gentamicin, against 17 strains of P. aeruginosa (8) and S. aureus (9) isolated from ocular infection and inflammation, and 1 reference strain of S. aureus. Corneas of C57BL/6 mice were topically challenged with a multidrug-resistant strain of P. aeruginosa. Nine hours post-challenge, mice were treated topically and hourly with either vehicle, B-LFcin, ciprofloxacin or ciprofloxacin containing B-LFcin for 8 h. Corneas were then clinically examined, and bacterial numbers and levels of myeloperoxidase (MPO) evaluated. Synergy between B-LFcin and ciprofloxacin or ceftazidime was identified in most P. aeruginosa isolates, including multidrug-resistant strains, whereas no synergistic effect was seen between B-LFcin and gentamicin. Synergy was only observed with B-LFcin and ciprofloxacin against 2/10 S. aureus strains, and there was no synergy between B-LFcin and any of the other antibiotics tested. Combined B-LFcin and ciprofloxacin treatment significantly improved the clinical outcome, and reduced bacterial numbers and MPO in infected mouse corneas. B-LFcin alone was also able to reduce levels of MPO in infected corneas. These findings indicate that B-LFcin may have advantages as an adjunct therapy with both antimicrobial and anti-inflammatory properties in the treatment of corneal infection.
Publisher: Elsevier BV
Date: 06-1994
DOI: 10.1016/0020-711X(94)90109-0
Abstract: 1. In the presence of polyethylene glycol, the self-association of human spectrin is enhanced in a manner that depends approx. exponentially on the mass concentration of polyethylene glycol. 2. For a given mass concentration, the enhancement is independent of the molecular weight of the polyethylene glycol. 3. These data are consistent with the operation of excluded volume effects, and support the contention that the association of spectrin is likely to be increased in the presence of the high concentration of hemoglobin within the erythrocyte in vivo.
Publisher: Wiley
Date: 19-10-2016
DOI: 10.1002/JBM.B.33804
Abstract: Lactoferrin and lactoferricin were immobilized on glass surfaces via two linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The antimicrobial activity of the surfaces was determined using Pseudomonas aeruginosa and Staphylococcus aureus strains by fluorescence microscopy. Lactoferrin and lactoferricin immobilization was confirmed by XPS showing significant increases (p < 0.05) in nitrogen on the glass surface. The immobilization of both proteins slightly increased the overall hydrophobicity of the glass. Both lactoferrin and lactoferricin immobilized on glass significantly (p < 0.05) reduced the numbers of viable bacterial cells adherent to the glass. For P. aeruginosa, the immobilized proteins consistently increased the percentage of dead cells compared to the total cells adherent to the glass surfaces (p < 0.03). Lactoferrin and lactoferricin were successfully immobilized on glass surfaces and showed promising antimicrobial activity against pathogenic bacteria. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2612-2617, 2017.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 02-2007
DOI: 10.1167/IOVS.06-0609
Abstract: HSV-1 has been shown to block apoptosis in some cell lines when the cells are exposed to exogenous agents (e.g., sorbitol). The purpose of this study was to determine whether HSV-1 infection of human corneal epithelial (HCE) cells alone induces an early proapoptotic response and whether this response is subsequently downregulated during the infection. HCE cells were infected with HSV-1 or subjected to osmotic shock (sorbitol). Fluorescent staining for annexin V binding, mitochondrial membrane potential, and DNA condensation and assays for caspase 8, 9, and 3 activity and cytokeratin 18 cleavage were performed, to assess the apoptotic pathway. HSV-1 infection of HCE cells induced a rapid proapoptotic response, characterized by translocation of phosphatidylserine to the external membrane, activation of caspases 8 and 3 within 2 hours, and cleavage of cytokeratin 18. However, the induced response was downregulated during the infection, and later stages of the apoptotic responses (e.g., DNA condensation) were not produced. Sorbitol treatment led to terminal apoptosis by 12 hours, as indicated by DNA condensation of treated cells and reduction in the number of viable cells. HSV-1 can induce and subsequently suppress the apoptotic pathway in HCE. Suppression of apoptosis occurred only during HSV-1 infection and not after treatment with sorbitol, suggesting that the suppression of apoptosis may be a mechanism of viral survival.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC90051D
Abstract: Correction for 'Visualising mouse neuroanatomy and function by metal distribution using laser ablation-inductively coupled plasma-mass spectrometry imaging' by Bence Paul et al. , Chem. Sci. , 2015, DOI: 10.1039/c5sc02231b.
Publisher: Informa UK Limited
Date: 2005
DOI: 10.1080/02713680590968583
Abstract: To determine the contribution of interleukin-4 (IL-4) to the initial host response during corneal infection with Pseudomonas aeruginosa in a mouse model. Corneas of 6- to 8-week-old IL-4(-/-) and wild-type mice were topically challenged with P. aeruginosa. Ocular tissue was collected 24 hr and 7 days postchallenge. Viable bacterial counts, myeloperoxidase assays, cytokine levels, and clinical and histological examinations were performed. During challenge with P. aeruginosa, no differences were observed clinically, histologically, or in bacterial load between IL-4(-/-) and wild-type mice at either time point. However, differences in cytokine levels of IL-6, KC, and IL-10 were observed. The data presented indicate that IL-4, a central Th2 cytokine, may not be critical to the pathogenesis or bacterial clearance in this model of P. aeruginosa bacterial keratitis during the early stages of the infectious process.
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.CLAE.2011.07.003
Abstract: Contact lens wear continues to be the highest single risk factor for microbial keratitis, particularly when worn in the extended wear modality. For microbial keratitis to occur, the presence of at least a bacterial load as well as a break in the corneal surface is required. One such break occurs in the case of a corneal erosion. These well-circumscribed areas of full thickness epithelial loss can occur both with and without contact lens wear, however the risk of infection is greater in the presence of a lens due to its capacity to provide a vector for the entry of bacterial pathogens. While erosions in non-contact lens wearers are thought to result from defective epithelial basement membrane anchoring, the underlying causes during contact lens wear are yet unknown. This article sets out to review corneal erosions associated with contact lens wear, their associated risk factors such as extended wear, the mechanisms that may be responsible for their formation and the factors that differentiate them from other contact lens related adverse events. Appropriate diagnosis and understanding of the relevant pathophysiology is important to the effective treatment and an understanding of the aetiological factors responsible for erosions is critical to the development of preventative strategies and effective clinical care.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 04-2009
DOI: 10.1167/IOVS.08-1882
Abstract: The purpose of this study was to investigate the effect of bovine lactoferrin (BLF) on human corneal epithelial wound healing using an in vitro alkali-induced wound model and to understand its role in promoting wound healing. Confluent human corneal limbal epithelial (HCLE) cells wounded using 0.5 microL of 0.1 M sodium hydroxide were treated with BLF (0, 0.1, 1, 2.5, and 5 mg/mL) or anti-human interleukin-6 (IL-6) receptor neutralizing antibody (anti-IL-6 antibody 1, 10, and 50 microg/mL) or tyrphostin AG1295 (an inhibitor of platelet-derived growth factor [PDGF] receptor kinase 1 and 10 microM), IL-6, or PDGF-BB. The conditioned medium collected for BLF treatment (0 and 5 mg/mL) was analyzed using a protein array for a number of cytokines/growth factors involved in corneal wound healing. A preliminary animal study using mice was carried out to determine the effect of BLF on alkali wounds. BLF at 2.5 and 5 mg/mL promoted wound healing (P<0.01). During wound closure, BLF upregulated PDGF-BB 180-fold and IL-6 10-fold compared with control. Treatment with tyrphostin AG1295 (10 microM P<0.01) or anti-IL-6 antibody (50 microg/mL P or=2.5 mg/mL stimulates HCLE wound healing, and this stimulation is mediated through the upregulation of PDGF or IL-6.
Publisher: American Society for Microbiology
Date: 06-2001
DOI: 10.1128/IAI.69.6.4116-4119.2001
Abstract: Lack of interleukin-6 (IL-6) during Pseudomonas aeruginosa corneal infection leads to more severe disease with changes in neutrophil recruitment. Exogenous IL-6 leads to increased efficiency of neutrophil recruitment and reduced bacterial loads in corneal infection in both IL-6 gene knockout and wild-type mice. This may be mediated by IL-6 increasing the production of corneal macrophage inflammatory protein 2 and intercellular cell adhesion molecule 1. We conclude that effective recruitment of neutrophils into the cornea is dependent on the production of IL-6 and that early augmentation of IL-6 may be protective in corneal infection.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9AN01580A
Abstract: Raw intensities obtained from the ablation of mould-prepared gelatine.
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.IJANTIMICAG.2010.02.005
Abstract: Melimine is a novel cationic peptide possessing broad-spectrum antimicrobial activity that is retained when attached to a surface, suggesting that interactions with bacterial membranes may be of primary importance to its activity. The effects of alterations in the environment on the conformation of melimine were investigated using circular dichroism and fluorescence spectra in membrane-mimetic solvents. Furthermore, the interactions of melimine with bacterial membranes of Pseudomonas aeruginosa and Staphylococcus aureus were examined using scanning electron and fluorescence microscopy, and perturbation of membrane integrity was tested by measurement of melimine-mediated diSC(3)-5 dye release from bacterial cells. Melimine has a predominantly random coil conformation that adopts a helical fold when exposed to organic solvents. However, when it is solubilised in micelles of sodium dodecyl sulphate, which are bacterial membrane-mimetic, the alpha-helical content increases to ca. 35-40%. A major effect of melimine was on the integrity of the cytoplasmic membrane both for P. aeruginosa and S. aureus. However, for P. aeruginosa the rapid loss of cytoplasmic membrane integrity correlated directly with loss of cell viability, whilst for S. aureus maximal dye release was obtained at concentrations where there was no significant loss of viability. There have been few studies to date investigating differences in the action of cationic peptides towards Gram-positive and Gram-negative bacteria. Consequently, further investigation of these mechanistic differences may allow more refined targeting of increasingly difficult-to-treat bacterial infections and/or further inform design of novel peptides with improved broad-spectrum activity.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2013
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 2010
DOI: 10.1167/IOVS.09-4068
Abstract: One strategy to minimize bacteria-associated adverse responses such as microbial keratitis, contact lens-induced acute red eye (CLARE), and contact lens induced peripheral ulcers (CLPUs) that occur with contact lens wear is the development of an antimicrobial or antiadhesive contact lens. Cationic peptides represent a novel approach for the development of antimicrobial lenses. A novel cationic peptide, melimine, was covalently incorporated into silicone hydrogel lenses. Confirmation tests to determine the presence of peptide and anti-microbial activity were performed. Cationic lenses were then tested for their ability to prevent CLPU in the Staphylococcus aureus rabbit model and CLARE in the Pseudomonas aeruginosa guinea pig model. In the rabbit model of CLPU, melimine-coated lenses resulted in significant reductions in ocular symptom scores and in the extent of corneal infiltration (P < 0.05). Evaluation of the performance of melimine lenses in the CLARE model showed significant improvement in all ocular response parameters measured, including the percentage of eyes with corneal infiltrates, compared with those observed in the eyes fitted with the control lens (P < or = 0.05). Cationic coating of contact lenses with the peptide melimine may represent a novel method of prevention of bacterial growth on contact lenses and consequently result in reduction of the incidence and severity of adverse responses due to Gram-positive and -negative bacteria during lens wear.
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.CHROMA.2016.01.054
Abstract: A novel microfluidic paper-based analytical device (μPAD) was designed to filter, extract, and pre-concentrate explosives from soil for direct analysis by a lab on a chip (LOC) device. The explosives were extracted via immersion of wax-printed μPADs directly into methanol soil suspensions for 10min, whereby dissolved explosives travelled upwards into the μPAD circular s ling reservoir. A chad was punched from the s ling reservoir and inserted into a LOC well containing the separation buffer for direct analysis, avoiding any further extraction step. Eight target explosives were separated and identified by fluorescence quenching. The minimum detectable amounts for all eight explosives were between 1.4 and 5.6ng with recoveries ranging from 53-82% from the paper chad, and 12-40% from soil. This method provides a robust and simple extraction method for rapid identification of explosives in complex soil s les.
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.RVSC.2007.11.006
Abstract: The first reference map of the proteome of pooled normal dog tears was created using 2-dimensional polyacrylamide gel electrophoresis and the identity of a number of the major species determined using matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF) and peptide mass fingerprint matching on protein sequence databases. In order to understand the changes in protein expression in the tear film of dogs with cancer, tears from such animals were similarly examined. A number of differences were found between the tears of healthy dogs and the dogs with cancer. Differences were found in levels of actin and albumin and in an unidentified protein which may be analogous to human lacryglobulin. These findings suggest that it may be possible to develop tear film analysis to provide a simple non-invasive test for the diagnosis and/or management of canine cancers.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CS00610A
Abstract: A ‘how-to’ guide for designing chemical imaging experiments using antibodies and immunohistochemistry.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Wiley
Date: 04-1999
DOI: 10.1046/J.1440-1711.1999.00805.X
Abstract: Pseudomonas aeruginosa can cause ulcerative bacterial keratitis or contact lens-induced acute red eye (CLARE) in humans. The present study used a mouse model of ocular infection and inflammation to examine the relationship between TNF-alpha and inflammation in the cornea in response to challenge with either a strain of P. aeruginosa causing keratitis or a CLARE strain. Constitutive TNF-alpha mRNA was detected in the epithelium, mainly towards the periphery. After infection with the keratitis-inducing strain (6294), TNF-alpha expression was elevated four-fold by 24 h post-challenge. No detectable induction of TNF-alpha mRNA was seen with CLARE strain (Paer1) challenge at any time point. The TNF-alpha protein production detected by ELISA showed a corresponding pattern to the mRNA expression, which also correlated with pathological changes. These results suggest that invasive strains of P. aeruginosa create greater pathological changes as a result of elevated TNF-alpha production, which contributes to inflammation during keratitis in vivo.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 09-2004
DOI: 10.1167/IOVS.03-1242
Publisher: Informa UK Limited
Date: 30-04-2009
DOI: 10.1080/08927010902954207
Abstract: Infection associated with implanted biomaterials is common and costly and such infections are extremely resistant to antibiotics and host defenses. Consequently, there is a need to develop surfaces which resist bacterial adhesion and colonization. The broad spectrum synthetic cationic peptide melimine has been covalently linked to a surface via two azide linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA), and the resulting surfaces characterized by X-ray photoelectron spectroscopy and contact angle measurements. The quantity of bound peptide was estimated by a modified Bradford assay. The antimicrobial efficacy of the two melimine-modified surfaces against Pseudomonas aeruginosa and Staphylococcus aureus was compared by scanning electron microscopy (SEM) and fluorescence microscopy. Attachment of melimine via ABA gave an approximately 4-fold greater quantity of melimine bound to the surface than attachment via FNA. Surfaces melimine-modified by either attachment strategy showed significantly reduced bacterial adhesion for both strains of bacteria. P. aeruginosa exposed to ABA-melimine and FNA-melimine surfaces showed marked changes in cell morphology when observed by SEM and a reduction of approximately 15-fold (p < 0.001) in the numbers of adherent bacteria compared to controls. For the ABA-melimine surface there was a 33% increase in cells showing damaged membranes (p = 0.0016) while for FNA-melimine there was no significant difference. For S. aureus there were reductions in bacterial adhesion of approximately 40-fold (p < 0.0001) and 5-fold (p = 0.008) for surfaces modified with melimine via ABA or FNA, respectively. There was an increase in cells showing damaged membranes on ABA-melimine surfaces of approximately 87% (p = 0.001) compared to controls, while for FNA-melimine there was no significant difference observed. The data presented in this study show that melimine has excellent potential for development as a broad spectrum antimicrobial coating for biomaterial surfaces. Further, it was observed that the efficacy of antimicrobial activity is related to the method of attachment.
Publisher: Informa UK Limited
Date: 07-2014
DOI: 10.1111/CXO.12147
Abstract: The greater prevalence of dry eye in women compared to men suggests that sex hormones may have a role in this condition. This review aims to present evidence for how sex hormones may affect the ocular structures involved in the production, regulation and maintenance of the normal tear film. It is hypothesised that hormone changes alter the homeostasis of the ocular surface and contribute to dry eye. Androgens impact on the structure and function of the meibomian and lacrimal glands and therefore androgen deficiency is, at least in part, associated with the aetiology of dry eye. In contrast, reports of the effects of oestrogen and progesterone on these ocular structures and on the conjunctiva are contradictory and the mechanisms of action of these female-specific sex hormones in the eye are not well understood. The uncertainty of the effects of oestrogen and progesterone on dry eye symptoms is reflected in the controversial relationship between hormone replacement therapy and the signs and symptoms of dry eye. Current understanding of sex hormone influences on the immune system suggests that oestrogen may modulate a cascade of inflammatory events, which underlie dry eye.
Publisher: Springer Science and Business Media LLC
Date: 13-02-2007
DOI: 10.1007/S10456-007-9063-3
Abstract: Corneal vascularisation is a potentially devastating occurrence that can cause blindness. Currently, treatments for this condition are limited. In these studies, we have investigated a novel inhibitor of angiogenesis, 12-methyl tetradecanoic acid (12-MTA), to treat corneal vascularisation in mouse models of corneal alkali injury and corneal Pseudomonas aeruginosa infection. The effectiveness of 12-MTA was compared to treatment with dexamethasone. 12-MTA was found to be at least as effective as dexamethasone in reducing the angiogenesis that occurs following alkali injury or P. aeruginosa infection of the cornea. The major effect of both 12-MTA and dexamethasone in these models was to reduce the linear incursion of new blood vessels into the central cornea. A significantly better result was obtained at 14 days post-alkali injury when treatment was not delayed. A major advantage of treatment of alkali injury with 12-MTA compared to that with dexamethasone was the finding that there was a 5-fold less level of PMN infiltration and no persistent epithelial defects in corneas treated with 12-MTA compared to 50% of those treated with dexamethasone. Our studies indicate that 12-MTA may provide clinically significant advantages over conventional steroids for the treatment of vessel growth in the cornea.
Publisher: Wiley
Date: 12-2000
DOI: 10.1046/J.1440-1711.2000.00946.X
Abstract: Intestinal parasitic infection is still a major problem in humans and animals, yet host immunity against gut parasitic infection remains partially understood. Eosinophilia and mastocytosis are features of such infection that have been shown to be genetically controlled. The expression of IL-6 is detected in eosinophils, mast cells and neutrophils and may be responsible for the regulation of leucocytes at infective sites. The relationships between IL-6 expression, eosinophilia, mastocytosis and host immunity remain unclear. In the present report, a close correlation between IL-6 mRNA+ cells, eosinophilia, mastocytosis and worm expulsion is demonstrated, which may indicate a role for IL-6 in regulation of host immunity against intestinal parasite infection.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 05-2003
DOI: 10.1167/IOVS.02-0565
Abstract: This study was conducted to investigate the role of IL-1beta in the regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in a mouse model of experimental keratitis and corneal injury. Mice were injected subconjunctivally with 10 micro g of anti-mouse IL-1beta antibody 2 hours before challenge with Pseudomonas aeruginosa (strain 6294). Control animals received an equal volume and concentration of isotype control antibody at the same time. Eyes were enucleated at 0, 8, 24, and 72 hours, after bacterial challenge and processed for histologic examination. Some eyes were homogenized and used to evaluate production of MMP-2, MMP-9, TIMP-1, and TIMP-2 protein, by zymography and reverse zymography. Injury without bacterial infection resulted in increases in both MMP-2 and -9 and a slight but significant downregulation of TIMP-1. Administration of anti-IL-1beta just before injury and without bacterial infection resulted in a significant reduction in expression of MMP-2 (at 8 hours), MMP-9 (at 8 hours), TIMP-1 (at 8 and 72 hours), and TIMP-2 (at 8 hours). Mice treated with anti-IL-1beta antibody, before bacterial challenge, demonstrated markedly reduced corneal damage compared with the severe corneal injury and massive neutrophil infiltration observed in infected mice treated with control antibody. Administration of the neutralizing anti-IL-1beta antibody resulted in a significant reduction of MMP-9 and a change in the time course of TIMP-1 and -2 expression. The reduction in MMP-9 by anti-IL-1beta during infection was much greater than the reduction without infection. The results imply that IL-1beta has a central role in corneal destruction during bacterial keratitis and suggests that targeting IL-1beta may be a novel therapeutic strategy for microbial keratitis.
Publisher: Elsevier BV
Date: 08-1994
DOI: 10.1016/0020-711X(94)90067-1
Abstract: The alpha-I fragment of human spectrin that carries the binding site on the alpha-chain of spectrin for the beta-chain has been purified from limited trypsin digests of spectrin by means of FPLC. The self-association of spectrin and the binding of the alpha-I fragment to spectrin heterodimers and to tetramers have been quantified through the use of gel electrophoresis, staining with Coomassie Blue, and quantification of the bound dye following elution with pyridine. The parameters of self-association were found to be consistent with those estimated from sedimentation equilibrium analysis. The data were consistent with a model in which both self-association and the binding of the alpha-I fragment are considered to occur through an intermediate in which the alpha-beta interface is initially dissociated. The alpha-beta interface in the heterodimer was found to be less stable than that of higher oligomers by approx. 3 kJ/mol.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.ACTBIO.2012.07.029
Abstract: Antimicrobial peptides (AMPs) are promising alternatives to current treatments for bacterial infections. However, our understanding of the structural-functional relationship of tethered AMPs still requires further investigation to establish a general approach for obtaining consistent antimicrobial surfaces. In this study, we have systematically examined the effects of surface orientation of a broad-spectrum synthetic cationic peptide, melimine, on its antibacterial activity against Gram-positive and Gram-negative bacteria. The attachment of melimine to maleimide-functionalized glass was facilitated by addition of a single cysteine amino acid into the peptide sequence at the N-terminus (CysN) or C-terminus (CysC), or at position 13 (Cys13, approximately central). The successful attachment of the modified melimine was monitored using X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) with principle component analysis. The ToF-SIMS analysis clearly demonstrated structural difference between the three orientations. The peptide density for the modified surfaces was found to be between 3.5-4.0×10(-9)molcm(-2) using a modified Bradford assay. The ability of the surfaces to resist Pseudomonas aeruginosa and Staphylococcus aureus colonization was compared using fluorescence confocal microscopy. Reductions in total P. aeruginosa and S. aureus adhesion of 70% (p<0.001) and 83% (p<0.001), respectively, after 48h were observed for the melimine s les when compared to the blank control. We found that melimine attached via the N-terminus was the most effective in reducing total bacterial adhesion and bacterial viability with two- and four times (p<0.001) more activity than melimine attached via the C-terminus for P. aeruginosa and S. aureus, respectively. Furthermore, for Cys13, despite having the highest measured peptide density of the three surfaces, the higher concentration did not confer the greatest antibacterial effect. This highlights the importance of orientation of the peptides on the surface to efficacy. Our results suggest that the optimal orientation of the cationic residues is essential for maximum surface activity, whereby the optimal activity is obtained when the cationic portion is more available to interact with colonizing bacteria.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2012
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.EXER.2014.07.016
Abstract: Staphylococcus aureus is a leading cause of corneal infection. CXC receptor 2 binding chemokines have been implicated in the pathogenesis of Pseudomonas aeruginosa keratitis. The role of this receptor in immune responses during Staphylococcus keratitis remains to be fully understood. Corneas of CXC receptor 2 knockout and wild-type mice (Cmkar -/- & Cmkar +/+) were scratched and 1 × 10(8) cfu/ml of strain Staph 38 applied. Twenty-four hours post-infection, mice were sacrificed and eyes harvested for enumeration of bacteria and measurement of myeloperoxidase levels. Production of inflammatory mediators, cellular adhesion molecules and chemokines in response to infection were investigated by ELISA, and PCR. 24 h after challenge with S. aureus, Cmkar -/- mice had developed a more severe response with a 50-fold higher bacterial load than WT mice. PMNs failed to penetrate the corneas of Cmkar -/- mice. However, concentrations of KC, MIP-2, IL-1β and IL-6 were significantly elevated (6-13 fold) in Cmkar-/- mice. The concentration of LTB4 was decreased (2 fold). Cmkar-/- mice failed to upregulate mRNA for VCAM-1 or PECAM-1 in response to infection, but had constitutively higher levels of ICAM-1. A lack of CXC receptor 2 lead to an inability to control bacterial numbers as a result of failure of PMNs to penetrate the cornea to the site of infection, even when chemokines were more highly produced. These results imply that CXCR2-mediated signaling through upregulation of adhesion molecules is essential to margination of PMNs in this infection model.
Publisher: Hindawi Limited
Date: 2014
DOI: 10.1155/2014/965403
Abstract: In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational s les. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR), although the “gold standard” for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX). This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7AY02294H
Abstract: We demonstrate the use of LA-ICP-MS for determining the location and quantification of silver in a rat spleen following nanoparticle exposure.
Publisher: Public Library of Science (PLoS)
Date: 22-08-2019
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