bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ocular rigidity and ocular response analyzer
Authors: IOMDINA E , ARUTUNYAN L , IGNATIEVA N , DANILOV N 
Published: September 2009

Abstract Purpose To study ocular rigidity and sclera crosslinking level at diferent stages of primary open angle glaucoma (POAG). Methods Biomechanical parameters of the eye especially corneal hysteresis (CH, mm Hg) were measured in 238 patients (311 eyes) aged 40‐84 (median age 67.4 yrs) at various stages of compensated primary open‐angle glaucoma using Reichert Ocular Response Analyzer (ORA). Besides, scleral samples obtained during sinus trabeculectomy combined with sclera trephination in the inferio‐exterior quadrant of 28 patients (28 eyes) with various stages of POAG were studied using differential scanning calorimetry (Mettler TA 4000 with DSC20 cell). Results Average value (median) of CH gradually decreased from 10.1 mm Hg in the initial glaucoma stage (I) to 9.1 mm Hg in the developed (II) and 8.6 mm Hg in the advanced (III) glaucoma stage. The decrease of this clinical parameter is caused by structural and biochemical damage of the corneoscleral coat. In stage I, endothermic scleral collagen transition occurred at the median thermal peak Tm=60.3 grad.C, while in stages II and III the median peaks of scleral collagen melting emerge at higher temperatures: Tm=62.0 grad.C and Tm=64.5 grad.C, respectively (p<0,05). This testifies to a significant increase of scleral cross‐linking and ocular rigidity during glaucoma development. Conclusion Biomechanical and biochemical disorders of glaucomatous sclera may cause clinical changes of ocular rigidity of eyes with POAG. This may be an important link of POAG pathogenesis requiring special therapy.
Ocular pulse amplitude under pressure: what happens to OPA in glaucoma before and after surgery?
Authors: STALMANS I , ZEYEN T , BREUSEGEM C 
Published: September 2009

Abstract Purpose To investigate whether trabeculectomy, besides its intraocular pressure (IOP) ‐ lowering effect, has an effect on the ocular pulse amplitude (OPA). To determine if OPA changes are influenced by IOP changes. Methods Forty‐eight glaucoma patients (48 eyes) scheduled for unilateral first‐time trabeculectomy were prospectively enrolled from October 2007 to April 2008. The eye undergoing trabeculectomy was considered as study eye, whereas the non‐operated fellow eye was used as control eye. OPA, IOP, blood pressure and heart rate were measured prior to and 4 weeks following trabeculectomy by means of Pascal dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT) and sphygmomanometry. A regression model for repeated measures was used. Results Preoperative GAT, DCT and OPA were 20.92 ±8.55 mmHg, 21.33 ±7.06 mmHg and 3.23 ±1.58 mmHg, respectively. One month following trabeculectomy, GAT, DCT and OPA were 11.23 ±5.03 mmHg, 14.45 ±4.79 mmHg and 2.12 ±1.07 mmHg, respectively. There was a significant decrease in OPA after filtering surgery in the study eye compared to the control eye (P<0.0001). Changes in OPA were correlated with changes in IOP (Spearman rho = 0.49, P=0.0004). When the IOP change caused by filtering surgery was taken into account, no significant difference in effect on the OPA following trabeculectomy could be demonstrated in the study eye compared to the control eye (P=0.18). Conclusion OPA changes were strongly correlated with IOP changes. There was no evidence for an effect of filtering surgery on the OPA when the concomitant IOP decrease after trabeculectomy was taken into account.
Visual and cognitive function in adolescents born with very low birth weight ‐ a 15‐ year follow‐up
Authors: HELLGREN K 
Published: September 2009

Abstract Purpose To describe visual functions in adolescents with VLBW in comparison with a matched control group and to investigate associations with white matter damage of immaturity (WMDI), optic disc measurements and cognitive functions in the VLBW group. Methods A total of 86 VLBW children survived the neonatal period during a 15 months period in the southeast region of Sweden. Fifty‐nine of those, and 55 term control infants, participated in the 15‐year follow‐up study. Structural assessments included brain MRI, digital analysis of fundus photographs and cycloplegic refraction. Functional evaluations comprised best corrected visual acuity, stereo acuity, visual fields, ocular alignment, cognitive visual problems and intellectual level. Results VLBW was significantly associated with smaller mean neural retinal rim area (in normal sized optic discs), subnormal visual acuity, subnormal stereo acuity and subnormal visual fields and increased frequency of astigmatism and ocular misalignment. Cognitive visual problems were more common and intelligence quotients were significantly lower in the VLBW group. WMDI occurred in 28% of the VLBW subjects. WMDI was significantly associated with visual field subnormality, myopia, ocular misalignment and cognitive visual problems. Subnormal results of performance subtests were associated with decreased visual and stereo acuity, ocular misalignment and cognitive visual problems. Conclusion This study confirms previous observations that adolescents with VLBW are at a disadvantage regarding visual and cognitive outcome compared with adolescents with normal birth weight. Adolescents with WMDI had more pronounced visual and cognitive dysfunction.
Eye alignment in low birth weight and/or prematurity
Authors: ARING E 
Published: September 2009

AbstractTo describe eye alignment in children with low birth weight and/or born prematurely. Through a review of published studies and personal observations, describe what we have learnt from the past for the future about eye alignment. This talk will focus on what we know about eye alignment in different levels of prematurity and body weight as well as describe eye alignment in different patient groups with high frequency of low birth weight and/or prematurity.
Update on risk factors and future perspectives for preterm infants
Authors: HELLSTRöM A 
Published: September 2009

Abstract Purpose To give an update on risk factors for retinopathy of prematurity with special focus on postnatal growth and growth factors Methods The relationship between birth weight, serum levels of IGF‐I as well as postnatal longitudinal growth and ROP will be presented. Preventive measures will be discussed. Results Birth weight data on 451 infants demonstrated initially a significant difference in BW between different ROP stages but when taking gestational age and sex into account the significance was eliminated. Recently, a new diagnostic tool based on weekly neonatal measurements of body weight and serum insulin‐like growth factor 1 (IGF‐I) levels, was shown to be predictive for ROP development. The algorithm “Weight IGF‐I Neonatal ROP” (WINROP™) predicted early (mean 10 weeks) all infants who later developed proliferative ROP requiring treatment. The WINROP algorithm was then taken one step further using only serial weight measurements (n=700), excluding blood sampling for measuring IGF‐I. With this approach WINROP predicted all infants who later developed proliferative ROP requiring treatment (100% sensitivity) and correctly identified 75% of those who did not develop proliferative ROP, and thus would not need any ophthalmologic screening. We have also shown a close relationship between postnatal growth, severe ROP and poor brain development. Conclusion For decades, neonatal intensive care has focused on survival of the most immature babies. Time has come to find methods to ameliorate the nutrition for the children born very preterm. It is known that IGF‐I is essential for growth and development of the immature vasculature of the eye. Intervention with substitution of IGF‐I to the very preterm babies to raise IGF‐I up to normal intrauterine levels might be beneficial.
Commercial interest
A new tissue‐polymer hybrid drug delivery system for artificial corneas
Authors: SHEN T , BARRETT R , GARTY S , KANAYAMA S 
Published: September 2009

Abstract Purpose We developed and evaluated a new hybrid tissue‐polymer drug delivery system using lyophilized cornea and synthetic hydrogel. The feasibility of this system as a carrier and a drug delivery system for an artificial cornea (Boston Keratoprosthesis) was evaluated in vitro while non‐modified cornea tissue was used as a control. Methods Corneal tissue from the eye bank was first lyophilized. The tissue‐polymer hybrid was synthesized by reconstituting the lyophilized cornea in a norfloxacin‐loaded hydrogel solution followed by polymerization. Four different tissue‐hydrogel compositions of varying hydrophobicity were synthesized and characterized over one month for the swelling and the drug release profile. Unmodified cornea tissue was used as a control. The mechanical strength and suture characteristics of the hybrid system and unmodified cornea were evaluated as a carrier for Boston K‐pro using an artificial anterior chamber. Results Both the hybrid‐system and the control show excellent mechanical properties as carriers for the Boston K‐pro. They withstood similar challenges of intrachamber pressures (50‐70 mmHg) for wound stability. In vitro drug release analysis demonstrates a longer and more controlled drug release profile for the hybrid system as compared to the control. The most hydrophobic hybrid construct shows a release that is above the Minimum Inhibitory Concentration 90 of Staphylococcus epidermidis for the first two days. Conclusion The new hybrid tissue‐polymer system shows sufficient mechanical stability to serve as a carrier for the Boston K‐pro. This system has the potential to simplify storage and distribution of donor tissue as a carrier for artificial cornea in developing countries where donor tissue is otherwise not readily available.
Retinal detachments after Boston keratoprosthesis: incidence, predisposing factors and outcomes of repair
Authors: JARDELEZA MS , DOHLMAN CH , YOUNG L 
Published: September 2009

Abstract Purpose Knowledge of predisposing factors to retinal detachments in certain patient populations can guide surgical planning in Boston keratoprosthesis placement. Methods This is a retrospective, noncomparative, interventional case series. A review of 166 patients (203 eyes) who underwent Boston Keratoprosthesis implantation at the Massachusetts Eye and Ear Infirmary from 1993 to 2008 was performed. Most patients had very advanced ocular disease. Predisposing factors to retinal detachment and details of timing after surgery were investigated. Anatomical and visual outcomes of retinal detachment repair were analyzed. Results Table 1. Retinal detachment after K‐Pro implantation Category Number of Eyes Eyes with RD Autoimmune systemic disease 72 24 (33%) Chemical burns 14 3 (21%) Non‐autoimmune etiology 117 10 (8.5%) Eighty‐nine (89%) of patients with retinal detachments have visual outcomes of less than 20/200 despite surgical repair. Majority of retinal detachments in all three subgroups occurred within the first six months after K‐Pro placement. Conclusion These data suggest that a retinal detachment following K‐Pro implantation is more frequent in patients with autoimmune disease (where K‐Pro is generally not recommended). When they do occur, they portend a poor visual prognosis. Patients with underlying autoimmune systemic disorders should be warned of the higher risk of developing retinal detachments after keratoprosthetic surgery and warrant close co‐management with a vitreoretinal specialist.
Inhibition of Notch pathway enhances photoreceptor commitment from cultured retinal stem cells
Authors: MONTAVON P , ARSENIJEVIC Y 
Published: September 2009

Abstract Purpose Consequently to the principle that photoreceptors have to be at a very precise development stage to be successfully transplanted (MacLaren 2006), we are trying to mimic this development stage in vitro using retinal stem cells. The latter were isolated from the newborn mouse retina, derived from the radial glia population, and were previously isolated and characterized in our laboratory. We developed a protocol to commit these cells to the photoreceptor fate, but even if the percentage of cells expressing photoreceptor markers is high (30%), the differentiation process is incomplete so far (Merhi‐Soussi 2006). Methods To ameliorate photoreceptor differentiation, we hypothesized that the Notch pathway may interfere with this process by either promoting glia commitment, or maintaining an undifferentiated state. We are thus using a gamma‐secretase inhibitor (DAPT), which inhibits Notch activation, during the in vitro differentiation process. Results The constant presence of DAPT i) leads to a 233% increase in peripherin/RDS‐positive (photoreceptor marker) cells, compared to controls (no DAPT, n=3, P<0.02) along with a 68% decrease in GFAP‐ positive cells (n=3, P<0.04), ii) modifies the ratio between uni‐/bi‐ (23%) and multi‐ (77%) polar peripherin/RDS‐positive cells to 45% and 55%, respectively, and iii) reduces by 50% the total cell number during the whole differentiation process. Conclusion We are now exploring whether this reduction in total cell number is due to inhibition of cell proliferation or to cell death and whether photoreceptor differentiation is promoted instead of glial induction. Such protocol may help to better mimic photoreceptor development, but this needs to be confirmed by genomic and proteomic profile analyses.
A new potential pharmacological target in diabetic retinopathy: the HuR pathway
Authors: AMADIO M , BUCOLO C , DRAGO F , GOVONI S , PASCALE A 
Published: September 2009

Abstract Purpose A key player within diabetic retinopathy is the Vascular Endothelial Growth Factor (VEGF) whose expression seems under Protein Kinase C (PKC) control, although no data are available on the molecular pathway underlying this process. Our previous in vitro work in retinal bovine pericytes (Amadio et al., Pharmacol Res. 57: 60, 2008) described a new molecular cascade involving PKCβ, the mRNA‐stabilizing protein HuR and VEGF. We investigated whether this pathway is operant also in vivo and altered by diabetes. Methods After 10 days treatment, retinal tissues from streptozotocin (STZ)‐induced diabetic rats were processed to detect PKCβI and βII, HuR and VEGF content. HuR activation/phosphorylation was also investigated. Immunoprecipitation coupled to real‐time quantitative PCR was employed to evaluate HuR binding to VEGF mRNA in ribonucleoproteic complexes (mRNP). The specificity of the PKCβ involvement was tested by experiments performed with a selective PKCβ inhibitor. Results In retinal tissues from STZ‐induced diabetic rats, PKCβI (+160%, p<0.01) and PKCβII (+113%, p<0.05) levels were increased versus sham. In the same STZ tissues a PKC‐mediated phosphorylation of HuR (+209%, p<0.01) occurred. A specific binding between HuR protein and VEGF mRNA was also detected in retinal mRNP. As well, the PKCβ/HuR activation was accompanied by enhanced VEGF protein expression (+256%, p<0.05). All these effects were blunted by a selective PKCβ inhibitor. Conclusion These findings first demonstrate the existence of the PKCβ/HuR/VEGF pathway in experimental diabetic retinopathy, suggesting that this cascade may represent a potential pharmacological target to counteract diabetic retinopathy, and more generally pathologies implicating VEGF deregulation.
Scanning beyond the limits of standard OCT: OCT scans of the peripheral retina and the anterior chamber angle with a slitlamp integtrated FD‐OCT system
Authors: STEHOUWER M , VERBRAAK FD , DE VRIES H , VAN LEEUWEN TG 
Published: September 2009

Abstract Purpose Exploring the quality of OCT images of the peripheral retina and anterior chamber angle made through a 3‐mirror contactlens and a new FD‐OCT device integrated into a slit lamp. Methods Patients with peripheral lesions (n=10) and glaucoma (n=10), seen in the outpatient clinic of the Academic Medical Center, were scanned with a Fourier Domain OCT integrated into a common Topcon slitlamp (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A‐scans per second, up to 1024 A‐scans per b‐scan). For posterior segment scans a fast Z‐tracking system in the reference arm compensates for the dynamic character (movements of patient, handheld lens, slitlamp) of the examination. Scans of peripheral lesions, and the anterior chamber angle were made with a 3‐mirror lens, while simultaneously the lesions were observed with the slitlamp. Results Scans of the peripheral retina obtained with a 3‐mirror lens with the FD‐OCT integrated into the slitlamp were of reasonably good quality and lesions, like peripheral laser scars, could be clearly identified. Compared to stand alone OCT systems, the integrated OCT system reached more peripheral lesions. The anterior chamber angle scanned through a 3‐mirror lens enabled scans of the angle structures. Conclusion It is possible to scan the peripheral retina and anterior chamber angle through a 3‐mirror contact lens with the slitlamp with integrated OCT. These scans could be of clinical interest in patients with pathology in the peripheral retina pathology or the anterior chamber angle.
The AMD‐associated complement factor H (CFH) polymorphism Y402H results in decreased CFH localisation to Bruch’s membrane
Authors: BISHOP PN , ZAMBRANO I , MORGAN BP , HAKOBYAN S , DAY AJ , CLARK SJ 
Published: September 2009

Abstract Purpose CFH down‐regulates the alternative pathway of the complement system by binding to polyanionic structures on host cells/tissues and inactivating surface associated C3b. Recently, the Y402H polymorphism in CFH has been shown to be a major risk factor for AMD. Here we investigated the functional consequences of the Y402H polymorphism by testing the hypothesis that the resultant amino acid substitution alters CFH binding to macular tissue Methods The 402H and 402Y forms of full‐length CFH and recombinant CFH fragments (composed of CCP6‐8) were labelled with different fluorophores (402Y with AlexFluor‐488 and 402H with AlexaFluor‐594). These were simultaneously incubated with frozen sections of human macular tissue from donor eyes and the relative binding of the two forms was investigated. In some experiments the tissue sections were digested with glycosidic enzymes prior to incubation with the fluorescently‐labelled proteins. Results Whilst the 402H and 402Y variants showed similar levels of binding to the RPE, there was a marked reduction in binding of the 402H form to Bruch’s membrane. The binding of both forms to Bruch’s membrane was dependent upon interactions with heparan sulfates, and to a lesser extent dermatan sulfates. Conclusion Complement mediated damage is important in the pathogenesis of AMD and the relative failure of the 402H form of CFH to localise to Bruch’s membrane may result in over activation of the complement system at the retinal pigment epithelium/Bruch's membrane interface.
Cytochrome C oxidase expression in retinal rod outer segment disks
Authors: BARABINO S , PANFOLI I , CALZIA D , ROLANDO M , MORELLI A 
Published: September 2009

Abstract Purpose The rod outer segment (ROS) plays a pivotal role in the phototransduction cascade, a process which requires a high level of energy consumption. In rods ATP production is confined to the mitochondria in the inner part, and the distances between sites of energy production and expenditure do not seem adequate to supply phototransduction. The goal of this study was to test the hypothesis that Cytochrome c oxydase (Cox) is located and catalytically active in ROS disk membranes. Methods Osmotically intact disks were isolated from 20 bovine retinal ROS obtained by sucrose gradient centrifugation in the presence of protease inhibitor cocktail and Ampicillin under dim red light at 4°C. Cox expression was studied by confocal laser scanning microscopy and semiquantitative Western‐immunoblotting, with a specific antibody. Cox activity in disks was investigated spectrophotometrically. Results Results from immunohystochemical confocal laser scanning microscopy, Western blot, and biochemical experiments suggest that Cox is uniformly distributed onto disks and therein catalytically active to an extent comparable to that of isolated mitochondria. Conclusion The expression and activity of Cox in bovine ROS disks is suggestive of an aerobic metabolism in ROS. This study opens new scenarios on the energy production in rods and on the possible role of its deficiency in some important retinal diseases which have not been clarified yet.
Keratinisation status and cytokeratins of the human Meibomian gland epithelium
Authors: KNOP E , LUDESCHER M , KNOP N 
Published: September 2009

Abstract Purpose The Meibomian gland (MG) is an indispensable component of the functional anatomy of the ocular surface. Increasing evidence points to a high impact of hyper‐keratinisation as a major cause of obstructive MG dysfunction (MGD) and evaporative dry eye. Information of normal keratinisation status and cytokeratin composition of the human MG is limited. Methods Conjunctival whole‐mount specimens including the lid margin from ten body donors of older age were embedded in paraffin. Serial sections were stained by H&E and Masson‐Goldner stain and by immunohistochemistry with an antibody panel to cytokeratins. Results In conventional stains, the MG shows distinct similarities with the pilo‐sebaceous unit of the cilia. The keratinised skin epithelium extended into the terminal part of the MG excretory duct similar to the hair follicle. Preliminary IHC results showed that the epithelium was positive there for the skin keratin CK10. Along the central duct the keratinisation CK10 expression was gradually lost similar to keratinisation marker involucrin. However, filaggrin, a marker for incipient stages of keratinisation and located in keratohyalin granules continued in the superficial layer of the duct epithelium all along the Meibomian central ductal system. CK14 a marker for basal undifferentiated cells showed a homogenous expression all along the basal cell layer of the MG ducts and the acini. Conclusion The MG shares similarities with the cilia in embryology, in structure and in the cytokeratin composition. It can hence be regarded as a “hair without a hair shaft”. All parts of the MG ducts have signs of incipient keratinisation and preserve a commitment to keratinisation. Upregulation in MGD explain hyper‐keratinisation as a typical event in obstructive MGD.
In search for correlation among markers for limbal stem cells niche
Authors: CURCIO C , CALIENNO R , LANZINI M , IEZZI M , MARIOTTI M , COLESANTI M , NUBILE M 
Published: September 2009

Abstract Purpose The corneoscleral limbus is known to be the site of corneal epithelial stem cells (SC). Several molecules have been proposed as SC markers but none of them is able to univocally identify them. The aim of this study was to evaluate co‐expression of different SC markers in human limbus. Methods In this work five corneoscleral specimens from normal human donor eye‐bank eyes (age 52‐73 years) were fixed in formalin, divided in 8 segments, embedded in paraffin and examined by immunohistochemistry and immunofluorescence for p63, vimentin (vim), laminin 5, integrin (Int) α6, Int β1, Int β4, connexin 43, ki67 and N‐cadherin positivity. We firstly analyzed the distribution and the anatomical structure of limbal crypts in each of the segments. Then we evaluated the percentage of positive areas in the niches. Finally we looked for colocalizations and possible correlations among markers. Results We confirmed a different number of niches among the segments of the same corneoscleral rim. Moreover we observed high variability of niches number among patients which interestingly correlates with the percentage of p63 positivity of niche cells. Confocal microscopy double staining for p63 and vim did not show evident colocalization and vim + cells were seen in the superficial layers rather than in the deep layer of crypts. Int β1 staining directly correlated with p63 positivity while the remaining proteins appeared variably and widely distributed Conclusion Colocalization was evident at least for two SC markers (Int β1/p63) within the basal layers, while vim, expressed mainly in the superficial layers could act as late progenitor cell marker.