10 research outputs found
Severe conjunctivochalasis in association with classic type Ehlers-Danlos syndrome.
RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Inferior conjunctivochalasis is common, but is rarely severe enough to require conjunctival excision. This report describes a patient with severe conjunctivochalasis who was subsequently diagnosed with Ehlers Danlos Syndrome, Classic Type. CASE PRESENTATION: A patient suffering from foreign body sensation, frequent blinking and bilateral inferior conjunctivochalasis was referred and treated by topical ocular lubrication. However, no improvement was observed prompting potential excision of conjunctivochalasis. Following patient consultation and clinical diagnosis including hypermobile joints and skin elasticity, poor wound healing and wide scar morphology, Ehlers-Danlos syndrome was confirmed in the patient. CONCLUSION: This case highlights the need for direct patient questioning and provides the first reported association between conjunctiovochalasis and Ehlers-Danlos syndrome
The visualisation of vitreous using surface modified poly(lactic-co-glycolic acid) microparticles
This paper is freely available online under the BMJ Journals unlocked scheme, see http:// bjo.bmj.com/site/about/unlocked.xhtmAims To demonstrate the potential use of in vitro poly (lactic-co-glycolic acid) (PLGA) microparticles in comparison with triamcinolone suspension to aid visualisation of vitreous during anterior and posterior vitrectomy. Methods PLGA microparticles (diameter 10-60 mu m) were fabricated using single and/or double emulsion technique(s) and used untreated or following the surface adsorption of a protein (transglutaminase). Particle size, shape, morphology and surface topography were assessed using scanning electron microscopy (SEM) and compared with a standard triamcinolone suspension. The efficacy of these microparticles to enhance visualisation of vitreous against the triamcinolone suspension was assessed using an in vitro set-up exploiting porcine vitreous. Results Unmodified PLGA microparticles failed to adequately adhere to porcine vitreous and were readily washed out by irrigation. In contrast, modified transglutaminase-coated PLGA microparticles demonstrated a significant improvement in adhesiveness and were comparable to a triamcinolone suspension in their ability to enhance the visualisation of vitreous. This adhesive behaviour also demonstrated selectivity by not binding to the corneal endothelium. Conclusion The use of transglutaminase-modified biodegradable PLGA microparticles represents a novel method of visualising vitreous and aiding vitrectomy. This method may provide a distinct alternative for the visualisation of vitreous whilst eliminating the pharmacological effects of triamcinolone acetonide suspension.Peer reviewedFinal Published versio
Political transition and emergent forest-conservation issues in Myanmar.
Political and economic transitions have had substantial impacts on forest conservation. Where transitions are underway or anticipated, historical precedent and methods for systematically assessing future trends should be used to anticipate likely threats to forest conservation and design appropriate and prescient policy measures to counteract them. Myanmar is transitioning from an authoritarian, centralized state with a highly regulated economy to a more decentralized and economically liberal democracy and is working to end a long-running civil war. With these transitions in mind, we used a horizon-scanning approach to assess the 40 emerging issues most affecting Myanmar's forests, including internal conflict, land-tenure insecurity, large-scale agricultural development, demise of state timber enterprises, shortfalls in government revenue and capacity, and opening of new deforestation frontiers with new roads, mines, and hydroelectric dams. Averting these threats will require, for example, overhauling governance models, building capacity, improving infrastructure- and energy-project planning, and reforming land-tenure and environmental-protection laws. Although challenges to conservation in Myanmar are daunting, the political transition offers an opportunity for conservationists and researchers to help shape a future that enhances Myanmar's social, economic, and environmental potential while learning and applying lessons from other countries. Our approach and results are relevant to other countries undergoing similar transitions
Political transition and emergent forest-conservation issues in Myanmar.
Political and economic transitions have had substantial impacts on forest conservation. Where transitions are underway or anticipated, historical precedent and methods for systematically assessing future trends should be used to anticipate likely threats to forest conservation and design appropriate and prescient policy measures to counteract them. Myanmar is transitioning from an authoritarian, centralized state with a highly regulated economy to a more decentralized and economically liberal democracy and is working to end a long-running civil war. With these transitions in mind, we used a horizon-scanning approach to assess the 40 emerging issues most affecting Myanmar's forests, including internal conflict, land-tenure insecurity, large-scale agricultural development, demise of state timber enterprises, shortfalls in government revenue and capacity, and opening of new deforestation frontiers with new roads, mines, and hydroelectric dams. Averting these threats will require, for example, overhauling governance models, building capacity, improving infrastructure- and energy-project planning, and reforming land-tenure and environmental-protection laws. Although challenges to conservation in Myanmar are daunting, the political transition offers an opportunity for conservationists and researchers to help shape a future that enhances Myanmar's social, economic, and environmental potential while learning and applying lessons from other countries. Our approach and results are relevant to other countries undergoing similar transitions
Tissue transglutaminase (TG-2) modified amniotic membrane : a novel scaffold for biomedical applications
The amniotic membrane (AM) is considered as a natural cell culture substrate and has occasionally been exploited in regenerative medicine especially for ocular surface reconstruction and dermal wound healing applications. However, its use is limited by its relatively weak mechanical strength, difficulty during manual handling and susceptibility to proteolytic degradation in vivo. Therefore, in this study we aimed to enhance the mechanical and biological characteristics of the AM by enzymatically cross-linking it using tissue transglutaminase (TG)-a calcium-dependent enzyme capable of forming stable ε(γ-glutamyl)lysine cross-linkages. Using a biological catalyst such as TG does not only prevent denaturation during sample preparation but also minimizes the potential of residual chemical cross-linking agents compared to alternative methodologies. Human AM, sourced from elective caesarean sectioning, were treated with TG, bovine serum albumin and/or a no-treatment control. Samples were then compared in terms of their physical and (scanning electron microscopy (SEM), transparency, mechanical strength, susceptibility to proteolytic degradation) biological characteristics (in vitro cell culture, activation of dendritic cells (DC)) and their in vivo biocompatibility/angiogenic capacity (chick chorioallantoic membrane assay). TG-treated AM exhibited enhanced mechanical strength and greater resistance to proteolytic/collagenase degradation compared to the control(s). SEM imaging of the TG-treated membrane summarized a significantly closer association and greater interconnectivity of individual collagen fibres yet it had no effect on the overall transparency of the AM. In vitro cell culture demonstrated no detrimental effect of TG-treatment on the AM in terms of cell attachment, spreading, proliferation and differentiation. Moreover, an 'immune response' was not elicited based on extended in vitro culture with human-monocyte-derived DC. Interestingly, the TG-treated AM still allowed angiogenesis to occur and in some instances, demonstrated an enhancement compared to the control (n = 5). We hereby demonstrate that treating the AM with the cross-linking enzyme, TG, results in a novel biomaterial with enhanced mechanical and biological characteristics. Above all, this modified membrane demonstrates greater strength, maintains in vitro cell growth, retains optical transparency and allows angiogenesis to occur without inducing an immune response. Altogether, this study demonstrates the feasibility of TG as an alternate cross-linking treatment for the production of novel biomaterials and suggests that TG-treated AM may now be more commonly exploited as a therapeutic dressing for ocular or wound applications.Peer reviewe
Influence of stereopsis on the ability to perform simulated microsurgery
Purpose: To determine whether impaired or absent stereopsis affects the ability to perform simulated microsurgical tasks.Setting: University of Edinburgh, United Kingdom.Design: Prospective randomized cross-over study.Methods: Visual acuity and stereoacuity were measured. A band-pass filter was placed over the nondominant eye to reduce stereoacuity to 150 seconds of an arc (partial stereopsis), or the nondominant eye was completely occluded (absent stereopsis). Participants completed a computerized surgical simulator task 3 times with a randomized testing order (normal stereopsis, absent stereopsis, and partial stereopsis). The task involved using forceps to grasp and position objects in the anterior chamber. Outcomes included area of ocular injury, time to task completion, and overall score.Results: Ocular damage area was significantly worse with partial stereopsis (P = .002) and worse still when stereopsis was absent (P < .001 for normal vs absent stereopsis and P = .005 for partial vs absent stereopsis). The median ocular damage area was 3.55 mm2 (interquartile range [IQR], 1.21-5.88 mm2) with normal stereopsis, increasing to 6.10 mm2 (IQR, 3.96-12.47 mm2) with stereopsis reduced to 150 seconds of an arc and to 9.25 mm2 (IQR, 4.93-18.70 mm2) with no stereopsis. Time taken to complete the task increased and overall score decreased as stereopsis was reduced. The overall score decreased from 53% (IQR, 22.5-82%) under normal stereopsis to 0% (IQR, 0-43.5%) with absent stereopsis.Conclusions: Impaired stereopsis was associated with worse microsurgical performance, which may have implications for surgical training. The absence of stereopsis resulted in worse performance than partial reduction in stereopsis.A prospective randomized cross-over study showed impaired stereopsis, both total absence and partial impairment, were associated with worse simulated microsurgical performance
Influence of stereopsis on the ability to perform simulated microsurgery
Purpose: To determine whether impaired or absent stereopsis affects the ability to perform simulated microsurgical tasks.Setting: University of Edinburgh, United Kingdom.Design: Prospective randomized cross-over study.Methods: Visual acuity and stereoacuity were measured. A band-pass filter was placed over the nondominant eye to reduce stereoacuity to 150 seconds of an arc (partial stereopsis), or the nondominant eye was completely occluded (absent stereopsis). Participants completed a computerized surgical simulator task 3 times with a randomized testing order (normal stereopsis, absent stereopsis, and partial stereopsis). The task involved using forceps to grasp and position objects in the anterior chamber. Outcomes included area of ocular injury, time to task completion, and overall score.Results: Ocular damage area was significantly worse with partial stereopsis (P = .002) and worse still when stereopsis was absent (P < .001 for normal vs absent stereopsis and P = .005 for partial vs absent stereopsis). The median ocular damage area was 3.55 mm2 (interquartile range [IQR], 1.21-5.88 mm2) with normal stereopsis, increasing to 6.10 mm2 (IQR, 3.96-12.47 mm2) with stereopsis reduced to 150 seconds of an arc and to 9.25 mm2 (IQR, 4.93-18.70 mm2) with no stereopsis. Time taken to complete the task increased and overall score decreased as stereopsis was reduced. The overall score decreased from 53% (IQR, 22.5-82%) under normal stereopsis to 0% (IQR, 0-43.5%) with absent stereopsis.Conclusions: Impaired stereopsis was associated with worse microsurgical performance, which may have implications for surgical training. The absence of stereopsis resulted in worse performance than partial reduction in stereopsis.A prospective randomized cross-over study showed impaired stereopsis, both total absence and partial impairment, were associated with worse simulated microsurgical performance
An in vitro assessment of the thermoreversible PLGA-PEG-PLGA copolymer: Implications for Descemet's membrane endothelial keratoplasty
An in vitro assessment of the thermoreversible PLGA-PEG-PLGA copolymer: Implications for Descemet's membrane endothelial keratoplasty
Background: To explore the use of a thermoreversible copolymer gel coating to prevent donor tissue scrolling in Descemet's membrane endothelial keratoplasty (DMEK). Methods: PLGA-PEG-PLGA triblock copolymer was synthesised via ring opening polymerisation. Two formulations were fabricated and gelation properties characterised using rheological analyses. Endothelial cytotoxicity of the copolymer was assessed using a Trypan Blue exclusion assay. Thickness of the copolymer gel coating on the endothelial surface was analysed using anterior segment optical coherence tomography (OCT) (RTVue-100, Optovue Inc.). Gold nanoparticles were added to the copolymer to aid visualisation using OCT. Prevention of Descemet membrane donor scrolling was represented via a novel, in vitro, immersion of copolymer coated donor graft material. Results: Two different formulations of PLGA-PEG-PLGA copolymer were successfully fabricated and the desired peak gelling temperature of 24°C was achieved by polymer blending. Application of 20%, 30% and 40% (wt/vol) polymer concentrations resulted in a statistically significant increase in polymer thickness on the endothelium (p < 0.001). There was no detectable endothelial cytotoxicity. The polymer was easy to apply to the endothelium and prevented scrolling of the DMEK graft. Conclusion: This PLGA-PEG-PLGA thermoreversible copolymer gel could be exploited as a therapeutic aid for preventing DMEK graft scrolling