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Michael Ekuoba Gyasi - One of the best experts on this subject based on the ideXlab platform.
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Burkholderia cepacia , a cause of post pars plana vitrectomy silicone oil related endophthalmitis: clinico-pathological presentation and outcome of management
International journal of retina and vitreous, 2018Co-Authors: Ogugua Ndubuisi Okonkwo, Olufemi Oderinlo, Ao Hassan, Michael Ekuoba GyasiAbstract:To report the long-term outcome of the management of a series of culture proven post pars plana vitrectomy endophthalmitis in which the infective agent was in the silicone oil used as an endotamponade. The isolates were Burkholderia cepacia and Pseudomonas aeruginosa. A retrospective interventional reporting of a series consisting of a cluster of five cases. Five consecutive patients received the same batch of 5000-centistoke silicone oil as endotamponade at the conclusion of vitreoretinal surgery and presented with features of acute intraocular inflammation, which was due to an infective cause. The infective organism isolated from the mixture of silicone oil and fluid was B. cepacia in three out of the initial cluster of four eyes and P. aeruginosa in the fifth eye. The initial 4 eyes evolved into eyes with poor vision (hand motion, perception of light and no perception of light), advanced proliferative vitreoretinopathy, hypotony, phthisis bulbi and Cornea Opacity. The poor visual outcome was deemed to be consequent to delay in removal of the silicone oil, despite use of intravitreal, systemic and topical antibiotics. The fifth case, because of the heightened index of suspicion gained from the preceding four cases, had a prompt removal of the silicone oil, vitreal lavage with antibiotics, and intravitreal injection of antibiotics and steroid. He regained a 6/9 vision. Gram-negative bacilli can colonize silicone oil resulting in post pars plana vitrectomy endophthalmitis. The index of suspicion for this should be high and can be managed successfully with prompt removal of the silicone oil, microbial sensitive antibiotic lavage of the vitreous cavity, followed by a repeat tamponade.
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Burkholderia cepacia, a cause of post pars plana vitrectomy silicone oil related endophthalmitis: clinico-pathological presentation and outcome of management
BMC, 2018Co-Authors: Ogugua Ndubuisi Okonkwo, Adekunle Olubola Hassan, Olufemi Oderinlo, Michael Ekuoba GyasiAbstract:Abstract Aim To report the long-term outcome of the management of a series of culture proven post pars plana vitrectomy endophthalmitis in which the infective agent was in the silicone oil used as an endotamponade. The isolates were Burkholderia cepacia and Pseudomonas aeruginosa. Method A retrospective interventional reporting of a series consisting of a cluster of five cases. Cases Five consecutive patients received the same batch of 5000-centistoke silicone oil as endotamponade at the conclusion of vitreoretinal surgery and presented with features of acute intraocular inflammation, which was due to an infective cause. The infective organism isolated from the mixture of silicone oil and fluid was B. cepacia in three out of the initial cluster of four eyes and P. aeruginosa in the fifth eye. Outcome of management The initial 4 eyes evolved into eyes with poor vision (hand motion, perception of light and no perception of light), advanced proliferative vitreoretinopathy, hypotony, phthisis bulbi and Cornea Opacity. The poor visual outcome was deemed to be consequent to delay in removal of the silicone oil, despite use of intravitreal, systemic and topical antibiotics. The fifth case, because of the heightened index of suspicion gained from the preceding four cases, had a prompt removal of the silicone oil, vitreal lavage with antibiotics, and intravitreal injection of antibiotics and steroid. He regained a 6/9 vision. Conclusion Gram-negative bacilli can colonize silicone oil resulting in post pars plana vitrectomy endophthalmitis. The index of suspicion for this should be high and can be managed successfully with prompt removal of the silicone oil, microbial sensitive antibiotic lavage of the vitreous cavity, followed by a repeat tamponade
Ogugua Ndubuisi Okonkwo - One of the best experts on this subject based on the ideXlab platform.
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Burkholderia cepacia , a cause of post pars plana vitrectomy silicone oil related endophthalmitis: clinico-pathological presentation and outcome of management
International journal of retina and vitreous, 2018Co-Authors: Ogugua Ndubuisi Okonkwo, Olufemi Oderinlo, Ao Hassan, Michael Ekuoba GyasiAbstract:To report the long-term outcome of the management of a series of culture proven post pars plana vitrectomy endophthalmitis in which the infective agent was in the silicone oil used as an endotamponade. The isolates were Burkholderia cepacia and Pseudomonas aeruginosa. A retrospective interventional reporting of a series consisting of a cluster of five cases. Five consecutive patients received the same batch of 5000-centistoke silicone oil as endotamponade at the conclusion of vitreoretinal surgery and presented with features of acute intraocular inflammation, which was due to an infective cause. The infective organism isolated from the mixture of silicone oil and fluid was B. cepacia in three out of the initial cluster of four eyes and P. aeruginosa in the fifth eye. The initial 4 eyes evolved into eyes with poor vision (hand motion, perception of light and no perception of light), advanced proliferative vitreoretinopathy, hypotony, phthisis bulbi and Cornea Opacity. The poor visual outcome was deemed to be consequent to delay in removal of the silicone oil, despite use of intravitreal, systemic and topical antibiotics. The fifth case, because of the heightened index of suspicion gained from the preceding four cases, had a prompt removal of the silicone oil, vitreal lavage with antibiotics, and intravitreal injection of antibiotics and steroid. He regained a 6/9 vision. Gram-negative bacilli can colonize silicone oil resulting in post pars plana vitrectomy endophthalmitis. The index of suspicion for this should be high and can be managed successfully with prompt removal of the silicone oil, microbial sensitive antibiotic lavage of the vitreous cavity, followed by a repeat tamponade.
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Burkholderia cepacia, a cause of post pars plana vitrectomy silicone oil related endophthalmitis: clinico-pathological presentation and outcome of management
BMC, 2018Co-Authors: Ogugua Ndubuisi Okonkwo, Adekunle Olubola Hassan, Olufemi Oderinlo, Michael Ekuoba GyasiAbstract:Abstract Aim To report the long-term outcome of the management of a series of culture proven post pars plana vitrectomy endophthalmitis in which the infective agent was in the silicone oil used as an endotamponade. The isolates were Burkholderia cepacia and Pseudomonas aeruginosa. Method A retrospective interventional reporting of a series consisting of a cluster of five cases. Cases Five consecutive patients received the same batch of 5000-centistoke silicone oil as endotamponade at the conclusion of vitreoretinal surgery and presented with features of acute intraocular inflammation, which was due to an infective cause. The infective organism isolated from the mixture of silicone oil and fluid was B. cepacia in three out of the initial cluster of four eyes and P. aeruginosa in the fifth eye. Outcome of management The initial 4 eyes evolved into eyes with poor vision (hand motion, perception of light and no perception of light), advanced proliferative vitreoretinopathy, hypotony, phthisis bulbi and Cornea Opacity. The poor visual outcome was deemed to be consequent to delay in removal of the silicone oil, despite use of intravitreal, systemic and topical antibiotics. The fifth case, because of the heightened index of suspicion gained from the preceding four cases, had a prompt removal of the silicone oil, vitreal lavage with antibiotics, and intravitreal injection of antibiotics and steroid. He regained a 6/9 vision. Conclusion Gram-negative bacilli can colonize silicone oil resulting in post pars plana vitrectomy endophthalmitis. The index of suspicion for this should be high and can be managed successfully with prompt removal of the silicone oil, microbial sensitive antibiotic lavage of the vitreous cavity, followed by a repeat tamponade
Phillip L. Casterton - One of the best experts on this subject based on the ideXlab platform.
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Corneal permeability in a redesigned Corneal holder for the bovine Cornea Opacity and permeability assay
Toxicology in vitro : an international journal published in association with BIBRA, 2004Co-Authors: John L. Ubels, Jonathon A. Ditlev, D.p. Clousing, Phillip L. CastertonAbstract:The bovine Cornea Opacity and permeability assay (BCOP) is a proposed alternative to the Draize rabbit test for potential eye irritants. In the standard BCOP, bovine Corneas are mounted in a holder on a flat surface between two identical chambers. The flat configuration of the standard holder does not conform to the normal curved shape of the bovine Cornea and it comes into direct contact with the Cornea tissue. Mounting Corneas in this holder causes extensive damage to both epithelial and endothelial Corneal cell layers. Our laboratory has designed a new holder that allows the Cornea to maintain its natural curvature and does not damage the Cornea. Previous tests, using both the new and standard holders, and comparing Corneal Opacity, hydration and endothelial morphology, have shown that the new holder is a significant improvement over the standard holder. The present study extends the comparisons of the new and standard holders to measurement of Corneal fluorescein permeability. The permeability (ng/cm(2)/min) of intact Corneas, Corneas with no epithelium, and Corneas treated with 1% NaOH, isopropanol, acetone, 30% trichloroacetic acid or 30% sodium dodecysulfate for either 1 or 10 min was determined by measuring fluorescence of samples taken from the endothelial chamber after 90 min epithelial exposure to 0.04% sodium fluorescein. In all trials, the redesigned holders yielded not only lower permeability measurements but also decreased measurement variability. The data provide further evidence that the new holder is an improvement over the standard holder and should be incorporated into a new protocol for the BCOP.
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A redesigned Corneal holder for the bovine Cornea Opacity and permeability assay that maintains normal Corneal morphology.
Toxicology in vitro : an international journal published in association with BIBRA, 2002Co-Authors: John L. Ubels, James Paauw, Phillip L. Casterton, D.j. KoolAbstract:The bovine Cornea Opacity and permeability assay (BCOP) has been in use for nearly 10 years but has not been submitted for regulatory approval. In previous reports we have presented Corneal hydration and endothelial damage as additional endpoints in this assay and have suggested that the design of the BCOP's Corneal holder should be modified. The standard holder used in the BCOP assay induces physical damage to the Cornea because it contacts clear Cornea causing edge damage to the epithelial, stromal and endothelial layers. Second, by forcing a curved, oval-shaped bovine Cornea into a flat, circular opening, Corneal wrinkling occurs which can alter the Cornea's optical characteristics and, most importantly, induces endothelial damage. We now report on a redesigned BCOP Corneal holder that clamps onto the sclera, maintains normal Corneal shape and does not cause damage to the endothelium. This ensures that irritancy tests are conducted using healthy, anatomically normal tissue. Tests of this holder using acetone, trichloroacetic acid, isopropanol and benzalkonium chloride show that it is now possible to evaluate effects of chemical substances on the endothelium. The effects of these compounds on Corneal Opacity and hydration in the new holder are similar to their effects on the Cornea in the standard holder.
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Corneal Opacity hydration and endothelial morphology in the bovine Cornea Opacity and permeability assay using reduced treatment times
Toxicology in Vitro, 2000Co-Authors: John L. Ubels, R M Pruis, J T Sybesma, Phillip L. CastertonAbstract:Abstract The purpose of this study was to determine whether the standard bovine Cornea Opacity and permeability (BCOP) assay exposure time of 10 minutes overestimates the ocular irritancy of chemical substances. Corneas were subjected to BCOP protocol following 30-second and 1-minute exposures to irritants. Corneal Opacity and hydration (mg H2O/mg Cornea) were then measured and compared to data obtained after 10 minute irritant treatments. For most test substances Corneal Opacity and hydration were lower following reduced exposure times. It is suggested that using shorter exposure times in BCOP protocol may be more predictive of human response to ocular irritants, since irritants are usually in brief contact with the ocular surface during accidental exposure. A second purpose of this study was to examine effects of irritants on the Corneal endothelium. Corneas were treated according to BCOP protocol following exposure to irritants for 1 or 10 minutes. The endothelium was stained with Alizarin Red and trypan blue, and examined using light microscopy. Severe irritants, such as NaOH and trichloroacetic acid, cause endothelial cell death. It was also determined that simply mounting the Cornea in the BCOP assay holders caused damage to 20% of the endothelial cells. Because the endothelium is essential for normal Corneal transparency and hydration, it is suggested that examination of the endothelium be added to the BCOP assay and that optimization of the assay will require modification of the Cornea holders.
Jun Sheng Lin - One of the best experts on this subject based on the ideXlab platform.
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An Insight into the Difficulties in the Discovery of Specific Biomarkers of Limbal Stem Cells.
International journal of molecular sciences, 2018Co-Authors: Zhi Hou Guo, Wei Zhang, Yang Yan Sheng Jia, Qing Xiu Liu, Jun Sheng LinAbstract:Keeping the integrity and transparency of the Cornea is the most important issue to ensure normal vision. There are more than 10 million patients going blind due to the Cornea diseases worldwide. One of the effective ways to cure Corneal diseases is Corneal transplantation. Currently, donations are the main source of Corneas for transplantation, but immune rejection and a shortage of donor Corneas are still serious problems. Graft rejection could cause transplanted Cornea Opacity to fail. Therefore, bioengineer-based Corneas become a new source for Corneal transplantation. Limbal stem cells (LSCs) are located at the basal layer in the epithelial palisades of Vogt, which serve a homeostatic function for the Cornea epithelium and repair the damaged Cornea. LSC-based transplantation is one of the hot topics currently. Clinical data showed that the ratio of LSCs to total candidate cells for a transplantation has a significant impact on the effectiveness of the transplantation. It indicates that it is very important to accurately identify the LSCs. To date, several putative biomarkers of LSCs have been widely reported, whereas their specificity is controversial. As reported, the identification of LSCs is based on the characteristics of stem cells, such as a nuclear-to-cytoplasm ratio (N/C) ≥ 0.7, label-retaining, and side population (SP) phenotype. Here, we review recently published data to provide an insight into the circumstances in the study of LSC biomarkers. The particularities of limbus anatomy and histochemistry, the limits of the current technology level for LSC isolation, the heterogeneity of LSCs and the influence of enzyme digestion are discussed. Practical approaches are proposed in order to overcome the difficulties in basic and applied research for LSC-specific biomarkers.
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An Insight into the Difficulties in the Discovery of Specific Biomarkers of Limbal Stem Cells
MDPI AG, 2018Co-Authors: Zhi Hou Guo, Wei Zhang, Yang Yan Sheng Jia, Qing Xiu Liu, Jun Sheng LinAbstract:Keeping the integrity and transparency of the Cornea is the most important issue to ensure normal vision. There are more than 10 million patients going blind due to the Cornea diseases worldwide. One of the effective ways to cure Corneal diseases is Corneal transplantation. Currently, donations are the main source of Corneas for transplantation, but immune rejection and a shortage of donor Corneas are still serious problems. Graft rejection could cause transplanted Cornea Opacity to fail. Therefore, bioengineer-based Corneas become a new source for Corneal transplantation. Limbal stem cells (LSCs) are located at the basal layer in the epithelial palisades of Vogt, which serve a homeostatic function for the Cornea epithelium and repair the damaged Cornea. LSC-based transplantation is one of the hot topics currently. Clinical data showed that the ratio of LSCs to total candidate cells for a transplantation has a significant impact on the effectiveness of the transplantation. It indicates that it is very important to accurately identify the LSCs. To date, several putative biomarkers of LSCs have been widely reported, whereas their specificity is controversial. As reported, the identification of LSCs is based on the characteristics of stem cells, such as a nuclear-to-cytoplasm ratio (N/C) ≥ 0.7, label-retaining, and side population (SP) phenotype. Here, we review recently published data to provide an insight into the circumstances in the study of LSC biomarkers. The particularities of limbus anatomy and histochemistry, the limits of the current technology level for LSC isolation, the heterogeneity of LSCs and the influence of enzyme digestion are discussed. Practical approaches are proposed in order to overcome the difficulties in basic and applied research for LSC-specific biomarkers
Yi Luo - One of the best experts on this subject based on the ideXlab platform.
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Prevalence and Causes of Visual Impairment in a Chinese Adult Population: The Taizhou Eye Study.
Ophthalmology, 2015Co-Authors: Yating Tang, Xiaofeng Wang, Jiucun Wang, Wei Huang, Yaping Gao, Yi LuoAbstract:Purpose To study the current prevalence and causes of low vision and blindness in an adult Chinese population. Design Population-based, cross-sectional study. Participants We used a random cluster sampling method and evaluated 10 234 eligible subjects ≥45 years old (response rate, 78.1%) in the Taizhou Eye Study. Methods Examinations were performed from July 2012 through December 2013. Participants underwent a detailed examination, including uncorrected visual acuity, best-corrected visual acuity (BCVA), intraocular pressure, axial length, slit-lamp, and fundus examinations to evaluate the prevalence and primary causes of visual impairment (VI). Main Outcome Measures We defined low vision and blindness according to the World Health Organization (WHO) criteria (low vision: BCVA, Results Using the WHO BCVA criteria, the standardized prevalence of bilateral low vision and blindness were 5.1% and 1.0%, respectively. Using the United States BCVA criteria, the standardized prevalence were 12.8% and 1.5%, respectively. Using the WHO criteria, the primary causes of bilateral low vision and blindness were cataract (59.1% and 48.5%, respectively), myopic macular degeneration (17.6% and 17.2%, respectively), and age-related macular degeneration (11.6% and 10.1%, respectively). The primary causes of monocular low vision were cataract (55.6%), age-related macular degeneration (12.6%), and myopic macular degeneration (8.9%), whereas those of monocular blindness were cataract (46.8%), atrophy of eyeball or prosthetic eye (10.2%), and Cornea Opacity (7.3%). A further analysis revealed that in adults 45-59 years old, myopic macular degeneration (59.6% and 27.2%, respectively) and cataract (13.8% and 23.4%, respectively) were the leading causes of bilateral and monocular VI. In adults ≥60 years old, cataract (66.8% and 61.2%, respectively) and age-related macular degeneration (12.6% and 11.8%, respectively) were the primary causes of bilateral and monocular VI. Conclusions The prevalence of low vision and blindness in Chinese adults remains a severe public health problem. In the Taizhou Eye Study, cataract was the leading cause of low vision and blindness. Myopic macular degeneration and cataract were the primary causes of VI in adults 45-59 years and ≥60 years old, respectively.