bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of human retinal pigment epithelial cells growth on elastin‐like recombinamers substrates
Authors: SRIVASTAVA GK , MARTIN L , SINGH AK , RODRIGUEZ‐CABELLO JC , PASTOR JC
Published: December 2011

Purpose In our previous published data (J Biomed Mater Res A. 2011) it was shown that ARPE19 cells were growing well and maintaining certain characteristics of RPE cells on the Elastin‐like recombinamers (ELR‐IK, ELR‐RGD). The purpose of this study is to evaluate the growth pattern of primary human RPE (hRPE) cells over these ELRs for possibility to start in‐vivo study as a possible treatment for AMD.

Methods hRPE cells were seeded on sterilized control surfaces (polystyrene, glass) as well as on ELR films that were obtained by solvent casting onto glass and subsequent cross‐linking containing a bioactive sequence, RGD (ELR‐RGD) and, without any specific sequence, as control (ELR‐IK). Cells were analyzed to study cell adhesion, proliferation, morphology and specific RPE antigen (RPE65) expression by staining with DAPI, Rhodamin‐phalloidin and antiRPE65 antibody at 12, 24, 72, 120, 168 and 360 hours.

Results hRPE cells seeded on ELR‐films as well as controls were proliferating; maintaining their similar morphology and expression of RPE65 antigen at different time points studied. Cells on ELR‐RGD were growing better than that on ELR‐IK and glass but lesser than that on polystyrene. The growth rate of hRPE cells over polystyrene and ELR‐RGD surfaces was increasing with time intervals than glass and ELR‐IK surfaces. There was a very clear difference of hRPE cells growth rate on different surfaces at 360 hours.

Conclusion ELR‐RGD was good substrate for hRPE cells growth and that maintained the similar morphology and RPE65 antigen expression as seen on control surfaces. These results require further in vitro and in vivo studies with hRPE cells to determine if ELR‐RGD could be useful as a vehicle for transplantation of hRPE cells in patients with AMD.
Trypan blue staining method for quenching the autofluorescence of RPE cells for improving protein expression analysis
Authors: SRIVASTAVA GK , REINOSO R , SINGH AK , CORELL A , FERNANDEZ‐BUENO1 I , HILEETO D , PASTOR JC
Published: December 2011

Purpose The purpose of this study is to develop and validate Flow Cytometry (FC) and Immunohistochemistry (IHC) methods for rapid and accurate measurements of cell proteins corresponding specific fluorescence signals above background noise using Trypan blue (TB) for quenching the autofluorescence (AF) emitted by Retinal pigment epithelial (RPE) and Ciliary body stem (CBSC)cells.

Methods RPE and CBSC cells were isolated, cultured and trypsinized using already published methods. AntiRPE65 immunolabelled cells were post treated with 10, 20 and 40 µg/ml TB at 4C for 10 min for FC analysis. 3‐5 mm small pieces of retinal tissue were pre treated with 20, 200 and 2000 µg/ml of TB at room temperature for 15 min, followed by embedding in paraffin wax, cutting into 3 µm thick retinal tissue sections (RTSs), dewaxing, anti RPE65 immunolabelling and observing under a microscope.Immunolabelling with isotype‐matched unspecific Abs, primary and secondary antibody were used as controls. Cytomicx RXP and Adope photoshop were used for FC and IHC results analysis.

Results FC and IHC results showed that post‐treatment of immunolabelled RPE cells and pre‐treatment of retinal tissue pieces with 20 µg/ml of TB reduce the AF and facilitate to detect the fluorescence signals corresponding to specific cell proteins with higher mean fluorescence intensity (MFI).

Conclusion We concluded: 1.‐Incubation of cells and tissues with 20 µg/ml of TB reduces AF. 2.‐For FC analysis, the cells should be post‐treated with TB and for IHC analysis, the tissues should be pre‐treated with TB. 3.‐The methods significantly increase the quality and value of cell protein analysis performed by FC and IHC techniques.
Aging and BDNF‐deficiency upregulates heat shock protein expression in mouse retina
Authors: PURANEN J , TUULOS T , VEHANEN K , RYHÄNEN T , UUSITALO H , KAARNIRANTA K , KALESNYKAS G
Published: December 2011

Purpose To examine heat shock protein (HSP) expression in retinas of mice that lack brain derived neurotrophic factor (BDNF+/‐) and their wild type littermates (WT) at young and old age.

Methods Eyes from 2‐ and 22‐months old WT and BDNF+/‐ mice (The Jackson Laboratory, Bar Harbor, ME, USA) were used. HSP 27 kDa (HSP27), 60 kDa (HSP60) and 70 kDa (HSP70) protein levels in retina were determined by Western blotting. Paraffin‐embedded retinal sections were immunostained for HSPs to determine their localisation and abundance in various retinal layers.

Results Western blot analysis of the whole retina showed a 2‐fold increase in HSP27 and HSP60, and a 1.5‐fold increase in HSP70 in aged WT mice as compared to young mice. The lack of BDNF significantly upregulated HSPs expression in retina. Thus, young BDNF+/‐ mice had similar expression levels of HSPs in retina as in old WT mice, whereas a further increase in HSPs expression was observed in aged BDNF+/‐ mice as compared to young BDNF+/‐ mice.

Conclusion Aging is associated with an increased expression of HSPs in the mouse retina. The lack of BDNF induces similar expression of stress‐related proteins in retina already at young age as it is seen at old age under normal BDNF levels.
Cholesterol from diet to the retina
Authors: LECERF JM
Published: December 2011

Plasma cholesterol is carried in the blood by lipoproteins. Lipoproteins contains lipids (free and esterified cholesterol, triglycerides, and phospholipids, and apolipoproteins). There are in the fasting condition three kinds of lipoproteins : very low‐density lipoproteins which are coming from the liver, and contain triglycerides and cholesterol ; low‐density lipoproteins which contain mainly cholesterol and apolipoprotein B, and high‐density lipoproteins which are involved in the reverse transport of cholesterol. Lipoproteins bring cholesterol to the tissues and cells which use it (gonads and adrenal glands, liver…) and triglycerides which are source of energy for muscle or are stored in adipose tissue The regulation of the plasma lipids metabolism is complex under genetic factors controlling receptors, apolipoprotein synthesis, and other proteins (for transfert, exchanges…). Dietary factors and metabolic factors such as abdominal adiposity may modulate the lipid metabolism. A lot of abnonnalities may affect the level of LDL or HDL cholesterol due to genetic defects, or nutritional diseases. The interpretation of a dyslipidemia often needs a global approach in order to identify the mechanisms, the consequences (cardiovascular risk) and the best treatment with hypolipidemic drugs and/or dietary changes.
Cholesterol, drusen and AMD
Authors: RUDOLF M
Published: December 2011

Abstract not provided
The effects of thermal sources emitted infrared radiation (IR) on rabbit corneal and crystalline lens extracellular molecules and the influence of cyclooxygenase (COX) inhibition
Authors: ALMALIOTIS D , DADOUKIS P , KARAMPATAKIS V , KARAKIOULAKIS G , PAPACONSTANTINOU E , KOMNINOU A
Published: December 2011

Purpose To investigate the effect of acute and chronic exposure to IR on rabbit corneal and lens metalloproteinase‐2 (MMP‐2), MMP‐9 and glycosaminoglycans (GAGs) and the influence of COX inhibition.

Methods Fourteen (14) New Zealand rabbits were used totally. Chronic exposure to IR included 4 month irradiation of 3 rabbits, whereas 3 animals were the control group. Regarding acute exposure, 8 rabbits were used, diclofenac sodium eye drops 0.1% were instilled in their right eyes and 4 of them were irradiated for 12 hours. By comparing the left irradiated with the left non‐irradiated eyes, the effect of IR exposure was investigated. COX inhibition role with and without IR exposure was determined, by comparing the left with the right eyes of the irradiated and the non‐irradiated rabbits separately.The cornea and lens were extracted, followed by gelatin zymography to determine MMP‐2 and MMP‐9 activity, GAGs isolation, measurement of uronic acids and electrophoresis on cellulose acetate membranes for GAGs analysis.

Results Chronic IR exposure induced the activity of corneal and lens pro‐MMP‐2 activity but did not affect GAGs. Acute exposure increased corneal and lens pro‐MMP‐2 activity and lens heparan sulfate amount, whereas the use of diclofenac sodium was unable to influence these effects.

Conclusion Corneal and lens acute and chronic IR exposure induced the activity of pro‐MMP‐2. Acute exposure, also, increased lens heparan sulfate amount.
Changes in retinal neuronal connectivity in a mouse model of dominant optic atrophy
Authors: WILLIAMS P , VON RUHLAND C , MORGAN J , VOTRUBA M
Published: December 2011

Purpose The heterozygous mutation, B6;C3‐Opa1Q285STOP which models autosomal dominant optic atrophy results in a 50% reduction in Opa1 transcript and protein in the mouse retina and neural tissues and is associated with visual dysfunction mirroring that found in human patients. We have previously reported retinal ganglion cell dendropathy in the absence of cell loss in this model. This study aims to explore the mechanisms that underlie this retinal ganglion cell dendropathy.

Methods Changes in retinal ganglion cell connectivity were explored in Opa1+/‐ mutant mice (n = 27) and accompanying age and sex matched controls (wt; n = 27) at 3 time points (12, 14 and 15 months of age) by immunohistochemistry, western blot analysis, TUNEL labelling and electron microscopy.

Results We report RGC dysfunction and changes in RGC connectivity in the absence of soma loss or microglial activation. We observed a dramatic decrease in PSD‐95 levels across all ages in the Opa1+/‐ mice suggesting synaptic atrophy coupled with a selective degeneration of glutamatergic but not GABA‐ergic synaptic sites. There was an increase in synaptic vesicle distribution assessed by immunohistochemistry, western blot and electron microscopy. γ‐synuclein labelling confirmed stable RGC populations without significant evidence of apoptosis on TUNEL staining.

Conclusion In conclusion; we show discrete changes in RGC connectivity localised to sublamina b. These results highlight the importance of normal mitochondrial fusion balance as influenced by the OPA1 protein in maintaining neural cell connectivity. Changes in connectivity precede the onset of clinical visual loss and structural changes in optic nerve in the absence of significant apoptosis or microglial upregulation.
Pupillometric quantification of residual rod and cone activity in patients with visual loss due to Leber congenital amaurosis
Authors: KAWASAKI A , MUNIER FL , LEON L , KARDON RH
Published: December 2011

Purpose Leber congenital amaurosis (LCA) is a group of genetically heterogeneous retinal dystrophies in which severe visual impairment occurs at infancy or during early childhood. We describe the threshold response function of rods and cones, as determined from pupil responses to colored light stimulation over a range of intensities, in 4 patients with LCA with different gene mutations who each had very poor visual function and non‐recordable ERG.

Methods Four subjects with LCA and 10 control subjects underwent computerized pupillography under conditions of dark adaptation. The pupil response to a 1 second red (640 ± 10nm) and blue (467 ± 17nm) Ganzfeld light from ‐4.0 to 2.0 log cd/m2 was recorded continuously. Pupil responses to low light intensities were used to define the response curve of rods and the rod threshold for blue and red light. When rod‐related pupil responses were absent, those obtained from red light stimulation at brighter intensities could be used to estimate cone activity.

Results A rod‐related pupil response curve was still preserved and defined in only one patient (RDH mutation) using blue light and the repsonse threshold was ‐3.1 log cd/m2 . This was almost 2 log‐units greater than the mean value in normal eyes (‐4.9 log cd/m2 blue light). Residual cone activity in all 4 LCA patients yielded response thresholds of ‐2.3, ‐0.9, ‐0.8 and ‐2.1 log cd/m2.

Conclusion Pupillometry can estimate residual function and threshold responses of rods and cones in advanced stages of LCA. As such, pupillometry expands the dynamic range of photoreceptor activity that can be objectively monitored, either to follow natural progression or to assess effects of intervention.

Commercial interest
Beijing Eye Public Health Care Project
Authors: JONAS JB , XU L , CUI TT , YOU QS , WANG YX , YANG H , LI JJ , WEI WB , LIANG QF , WANG S , YANG XH , ZHANG L
Published: December 2011

Purpose The Beijing Eye Public Health Care Project was designed to screen all elderly subjects (age 55‐85 years) of the rural region of Greater Beijing. It was developed as preparatory step for a telemedicine based public health care system in ophthalmology in China.

Methods Project participants were visited, interviewed and examined by 2500 trained barefoot doctors. If visual acuity was <0.3, subjects were referred to primary health care centers where ocular photographs were taken. Using telemedicine, the photographs were transmitted to a reading center and causes for visual impairment were diagnosed.

Results Out of 692,323 eligible inhabitants, 562,788 (81.3%) subjects participated. Visual impairment in at least one eye was detected in 54,155 (9.62%) subjects, and 30,164 (5.36%) subjects had bilateral visual impairment. Ocular fundus photographs were taken for 37,281 subjects. Cause for visual impairment was cataract in 19,163 (3.41%) of all screened subjects, glaucoma in 1,606 (0.29%) subjects, diabetic retinopathy in 905 (0.16%) subjects, other macular diseases in 2,700 (0.48%) subjects, pterygium in 1381 (0.25%) subjects, and corneal leukoma in 283 (0.05%) subjects. For 5,853 (1.04%) subjects, a diagnosis of urgent cataract surgery was made. After cataract surgery, visual acuity was ≥0.3 in 1464 (91.7%) of 1596 postoperatively re‐examined subjects.

Conclusion Using a telemedicine approach, the Beijing Eye Public Health Care Project developed, applied and tested an infrastructure for ophthalmic mass screening of more than 500,000 elderly inhabitants with a response rate of >80%. Besides cataract, retinal diseases including diabetic retinopathy and glaucoma were major causes for visual impairment.
Inhibition of mitocondrial complex IV in cell death and the influence of light.
Authors: OSBORNE N
Published: December 2011

Purpose Characterise the mechanism by which the mitochondrial complex IV poison sodium azide kills RGC‐5 cells (cell line with certain ganglion cell properties) in the dark and determine the influence of white and red light.

Methods RGC‐5 cell cultures in 96‐ or 12‐well plates were exposed to different concentrations of sodium azide in the dark or under white (400‐700nm, 1000 lux) or red (625‐635nm, 1000lux) light. Cells were analysed 24‐96 hours later for production of reactive oxygen species (ROS), cell viability (MTT procedure) and for apoptosis (staining for phosphatidylserine and DNA breakdown). Also, cultures were subjected to immunocytochemistry for the localisation of certain antigens or their proteins extracted and subjected to electrophoresis and western blotting for various proteins involved in cell death.

Results Sodium azide (5mM)‐induced apoptosis of RGC‐5 cells is characterised by positive membrane staining for phosphatidylserine, breakdown of DNA, a generation of ROS production, the activation of p38 MAPK and by inhibition with the caspase inhibitor z‐VAD‐fmk. Sodium azide also caused p38 MAPK to be translocated from the nucleus to the cytoplasm and the stimulation of alpha fordrin and caspase‐3 content. White light exacerbated and red light reduced the effects of sodium azide that occurred in the dark.

Conclusion Red light as opposed to white light acting directly on the retina might protect neurones from dying by apoptosis where their mitochondria are affected.
MHC‐II Glial upregulation in contralateral mice retina to experimental glaucoma
Authors: GALLEGO BI , DE HOZ R , RAMIREZ AI , SALAZAR JJ , ROJAS B , TRIVINO A , VALIENTE‐SORIANO FJ , SALINAS‐NAVARRO M , RAMIREZ JM
Published: December 2011

Purpose To analyze the effects of laser‐induced ocular hypertension (OHT) in MHC‐II expression in the glia of eyes with OHT (OHT‐eyes) and contralateral eyes two weeks after lasering.

Methods Adult Swiss mice were divided into two groups: naïve (n=6) and lasered (n=6). Retinal wholemounts were immunostained with antibodies against GFAP, Iba‐1 and MHC‐II.

Results In the naïve retinas, a weak constitutive MHC‐II expression was scarcely found in some Iba‐1+ cells and rarely in astrocytes. A small dendritiform subpopulation of Iba‐1+ cells, located in the juxtapapillary area and in the marginal region of the retina, had a strong MHC‐II immunoreaction. In comparison naïve results, in the contralateral eye, MHC‐II was expressed in Müller cells and was upregulated in Iba‐1+ cells as well as in the astrocytes. In contralateral macroglia, MHC‐II was preferentially expressed by astrocytes. In OHT‐eyes, Iba‐1+ cells showed MHC‐II immunoreactivity similar to contralateral and no MHC‐II astrocytes were observed; however, MHC‐II expression was upregulated in several groups of Müller cells thoroughout the retina and was preferentially located in the end‐foot of the cells.

Conclusion Two weeks of laser induced‐OHT produced macro and microglial retinal changes in MHC‐II expression in both, contralateral and OHT‐eyes. Our results suggest that the gliotic behavior in contralateral untreated eyes could be related to the immune response. On the basis of the glial changes observed, the use of the contralateral eye as a control in experimental unilateral OHT should be reconsidered.
A hypothesis about structural changes of the posterior pole based on scleral deformation during ocular movements
Authors: THEOCHARIS IP
Published: December 2011

Purpose To propose a theoretical model of the pathogenesis of various macular diseases based on structural deformation of the stratified posterior pole during ocular movements

Methods CT, MRI and OCT scans show evidence of significant deformation of the posterior sclera wall during ocular movements.The posterior pole is seen as a stratified model of multiple layers with different elastic properties.The morphology of lessions of various macular diseases is examined as a consequence of the compression of the stratified posterior pole using basic principles of mechanics.

Results The clinical expression of various macular diseases such as age‐related macular degeneration, macular hole, central serous choroidopathy could be explained by a unifying mechanism of structural changes that includes the role of the choroidal bed as a dampening stroma.

Conclusion The structural behavior of the multilayered stratified posterior pole during ocular movements may open a new field of research and treatment of the posterior pole diseases.
AICAR induces autophagy in ARPE‐19 cells
Authors: KAARNIRANTA K , VIIRI J , AMADIO M , HYTTINEN J , PAIMELA T , RYHÄNEN T , MARCHESI N , AKHTAR S , PASCALE A , PETROVSKI G , SALMINEN A
Published: December 2011

Purpose The pathogenesis of age‐related macular degeneration involves impaired protein degradation in retinal pigment epithelial (RPE) cells. The ubiquitin‐proteasome pathway and the lysosomal pathway including autophagy are the major proteolytic systems in eukaryotic cells. Recently, p62/sequestosome 1 (p62) has been shown to be a key player linking the proteasomal and lysosomal clearance systems. In the present study, the effects of AICAR (AICA ribonucleotide, 5‐aminoimidazole‐4‐carboxamide‐1‐β‐D‐ribofuranoside) and MG‐132 (proteasome inhibitor) on autophagy regulation in ARPE‐19 cells were evaluated.

Methods The AMP activated protein kinase (AMPK), p62 and ubiquitin protein levels were analyzed by western blotting. pDendra2‐hLC3 construct was used to detect macroautophagy in confocal microscopy analysis. Transmission electron microscopy was used to detect protein aggregates and autophagosomes. Cellular permeability was measured by analyzing lactate dehydrogenase levels in culture medium.

Results MG‐132 (5 microM) triggered the accumulation of perinuclear aggregates that strongly colocalized with p62 and ubiquitin. AICAR (2mM) induced autophagy clearance of p62 and ubiquitin positive protein aggregates without increasing cellular permeability. Cellular energy status regulator AMPK or p‐AMPK levels were not significantly changed in response to AICAR treatment.

Conclusion Our findings open new avenues for understanding the mechanisms of proteolytic processes and indicate that AICAR could be useful in the acceleration of protein clearance in RPE cells.
BDNF‐deficiency upregulates SIRT2 expression but does not affect cellular metabolism in mouse retina
Authors: PODRACKA L , VEHANEN K , TUULOS T , RÖNKKO S , KAARNIRANTA K , UUSITALO H , KALESNYKAS G
Published: December 2011

Purpose Brain derived neurotrophic factor (BDNF) is essential for cell development, function and survival. Mammalian sirtuins (SIRT) are deacetylase enzymes that are known to play an important role in longevity. In the present study we aimed to compare SIRT1 and SIRT2 expression in retinas of mice that lack brain derived neurotrophic factor (BDNF+/‐) and their wild type littermates (WT) at young age in relation to cellular metabolism.

Methods Eyes from 2‐months old WT and BDNF+/‐ mice (The Jackson Laboratory, Bar Harbor, ME, USA) were used. SIRT1 and SIRT2 protein levels in retina were determined by Western blotting. Paraffin‐embedded retinal sections were immunostained for SIRT1 and SIRT2 to determine their localisation and abundance in various retinal layers. Metabolic state of mouse retinal cells was assessed by measuring NAD+, NADH and total NAD levels using resazurin‐based assay.

Results Western blot analysis of the whole retina showed that SIRT1 expression is similar in WT and BDNF+/‐ mice. However, there was a significant upregulation of SIRT2 protein level in BDNF+/‐ mice compared to WT littermates. Assessment of NAD+, NADH and total NAD levels showed similar cellular metabolic state in retinas of WT and BDNF+/‐ mice.

Conclusion Our results indicate increased tubulin deacetylation in retinas of BDNF+/‐ mice, which is independent from cellular energy metabolism.
Effect of fixation and embedding methods on collagen fibrils diameter and spacing
Authors: AKHTAR S , ALMUBRAD T
Published: December 2011

Purpose The corneal tissue are usually fixed in fixatives and embedded in resin for ultrastructural studies. Here we study the effect of these fixatives and resins on the collagen fibril (CF) diameter and the spacing between the fibrils.

Methods Four normal human post‐mortem corneal buttons of 24, 25, 54 and 75 year old individuals were used. A part of each cornea was fixed in paraformaldehyde (4%) and embedded in LR White at 4°C under UV light for 24hrs. A second part of each cornea was fixed in glutaraldehyde (2.5%) + osmium tetroxide. The third part of each cornea was fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer for ultrastructural studies. The tissues were embedded in spurr resin at 70°C for 12 hrs. Ultra‐thin sections were stained with uranyle acetate and lead citrate.

Results In the tissue, fixed paraformaldehyde (4%) and embedded in LR White at 4°C under UV light for 24hrs, the CF diameter was 24± 0.1nm and spacing between CF was 39±0.1nm. In the tissue fixed in glutaraldehyde (2.5%) + osmium tetroxide, and embedded in spurr resin, the diameter was 28.37 ± 5.84nm and spacing between CF was 45 ±4.57nm. In the tissue, fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer and embedded in spurr resin, the diameter was 33.75 ± 3.65nm and spacing between CF was 48.06 ±4.35nm.

Conclusion Our study shows that there is a variation in the collagen fibril diameter and spacing depending on the method of fixation and embedding resins. This needs to be considered when comparative studies employing differ
Conjunctival antigen presenting cells: Sentinels for ocular surface inflammation
Authors: NIEDERKORN J
Published: December 2011

Purpose To evaluate the role of conjunctival antigen presenting cells (APC) in experimental dry eye disease (EDE) and in the immune rejection of corneal allografts.

Methods Ocular surface APC were depleted by subconjunctival injection of liposomes containing clodronate. APC depletion was confirmed by immunohistochemistry using anti‐CD11c (dendritic cells) and anti‐Iba1 (macrophages) antibodies. EDE was induced by exposing mice to desiccating stress (DS) for 5 days and pathogenic CD4+ T cells were to T cell‐deficient nude mice. Experiments were also performed in a murine model of keratoplasty.

Results Injection of clodronate liposomes produced 65% and 86% reductions in conjunctival macrophages and DC respectively. Depletion of APC prior to DS inhibited the generation of autoreactive CD4+ T cells and prevented EDE. APC deletion in nude mice prior to their receiving EDE‐producing CD4+ T cells significantly mitigated EDE. APC depletion prior to keratoplasty completely prevented corneal allograft rejection. However, depleting APC in nude mice prior to transferring CD4+ T cells did not affect corneal allograft rejection indicating that primed CD4+ T cells do not require secondary activation by APC to mediate graft rejection.

Conclusion Ocular surface APC play an important role in the generation of autoreactive pathogenic CD4+ T cells that mediate EDE and for secondary activation of these cells at sites of ocular surface inflammation. Ocular surface APC are also crucial for the induction of corneal allograft rejection, but secondary activation of previously primed allospecific CD4+ T cells by resident ocular surface APC is not required. Targeting ocular surface APC may be a facile therapeutic modality for managing ocular surface inflammation.
Radiation cataracts: epidemiology and biology
Authors: KLEIMAN N
Published: December 2011

Purpose The lens is one of the most radiosensitive tissues in the body. Ocular ionizing radiation exposure results in characteristic, dose related, progressive changes leading to cataract formation. While initial, early stages of such opacification may not cause visual disability, the severity of such changes progressively increases with dose until vision is impaired and cataract extraction surgery may be required. The latency of such changes is inversely related to dose. Within the past few months, the ICRP released new guidelines and recommendations concerning ocular ionizing radiation exposure, significantly lowering the presumptive threshold for radiation cataract to 0.5 Gy, regardless of acute, protracted or chronic exposure. Similarly, the occupational lens exposure limit was lowered, from 150 mSv/yr to an average of 20 mSv/yr over 5 years, with no single year exceeding 50 mSv.

Methods Recent human epidemiological studies have helped refine radiation cataract risk in various exposed populations. Nevertheless, considerable uncertainties remain concerning the precise pathobiology and the relationship between cataract development, age at exposure, threshold dose and genetic determinants of radiosensitivity.

Results Recent findings will be reviewed and new data on the genetic and individual basis of radiation cataract risk will be presented.

Conclusion New ICRP recommendations are likely to have significant implications for presumed radiation cataract risk, especially in radiosensitive individuals, as well as the need for occupational eye protection in fields such as interventional medicine. Cellular and molecular pathways leading to radiation cataract have fundamental relevance to that in other tissues and likely involves genomic damage, abberent division and abnormal differentation.
Mutation in Pxdn encoding peroxidasin causes small lenses and kinky tails in the mouse
Authors: GRAW J , WAGNER S , FUCHS H , HRABE DE ANGELIS M
Published: December 2011

Purpose The mouse mutant KTA48 was identified within the recessive Munich ENU Project among offspring of treated C3HeB/FeJ mice. It is characterized by a kinky tail, white belly spot and small dull eyes.

Methods Linkage analysis was performed using SNP‐based technology and microsatellite markers. Sequence analysis, histology and in‐situ hybridization were performed according to standard techniques.

Results The genome‐wide linkage analysis mapped the KTA48 mutation on chromosome 12; positional candidate gene analysis detected a mutation in the Pxdn gene (encoding peroxidasin) co‐segregating with the mutation. The Pxdn‐mRNA of the KTA48 mutants contains a T‐>A mutation at pos. 3816 (T3816A) creating a new Alw26I restriction site; the mutation converts the Cys at codon 1272 into a stop codon (Cys1272X). The mutation co‐segregates with the phenotype in the breeding colony; it is not present in several wild‐type strains. The lens phenotype is slightly variable. During an early stage of eye development (E12.5), Pxdn is expressed in the posterior part of the lens and in the central part of the retina without obvious changes. At the end of embryonic development (E17.5), we observed small lenses outside the optical axis and rupture of the lens capsule. Later, microphagia is accompanied by deformed cornea and multilayered retina. At P21, the small lens is attached to the cornea, and in some cases, the eye is completely disorganized..

Conclusion The recessive mouse mutation KTA48 is caused by a premature stop codon of the Pxdn gene. The function of Peroxidasin is still unknown; there is no mutation known neither in humans nor in mice.
Analysis of locus 2q13 in Ecuadorian family with keratoconus
Authors: NOWAK DM , KAROLAK JA , KUBIAK J , MOLINARI A , PITARQUE JA , BEJJANI BA , GAJECKA M
Published: December 2011

Purpose Keratoconus (KTCN) is described as a non‐inflammatory thinning and anterior protrusion of the central cornea which results in altered refractive powers, and loss of visual acuity. The etiology of KTCN remains unknown. Both genetic and environmental factors are associated with the disorder. The purpose of this study was to identify novel genetic factors involved in familial form of KTCN by extensive analysis of multigenerational Ecuadorian family.

Methods A total of 22 individuals from KTCN‐019 family were included into this study. Genomic DNA samples of all members of KTCN‐019 family were genotyped with highly polymorphic microsatellite markers. After linkage was established, two positional and functional candidate genes, IL1A and IL1B, were examined with polymerase chain reaction amplification, and direct sequencing of all exons, and intron‐exon boundaries was performed.

Results The disease susceptibility locus was mapped on 2q13 chromosome in KTCN‐019 family. Sequencing analysis of the candidate genes, IL1A and IL1B have revealed numerous alterations in coding and non‐coding sequences of both genes including several novel single nucleotide polymorphisms. No mutations segregated with KTCN phenotype have been identified.

Conclusion Analysis of IL1A and IL1B genes revealed no mutations segregating with affected phenotype in large Ecuadorian family, indicating that other genes are involved in KTCN causation in this family.
Towards Xeno‐free Differentiation of RPE Cells
Authors: ILMARINEN T , VAAJASAARI H , JUUTI‐UUSITALO K , NARKILAHTI S , SUURONEN R , UUSITALO H , SKOTTMAN H
Published: December 2011

Purpose Stem cell therapy is a potential approach for the replacement of degenerated retinal pigment epithelial (RPE) cells essential for vision. For therapeutical use, the differentiation of RPE cells from human pluripotent stem cells (hPSC) should be performed in a culture environment fulfilling clinical quality requirements. For example the use of xeno‐products should be avoided as this bears the danger of interspecies transfer of viruses and incorporation of immunogenic molecules.

Results Animal‐derived substances, such as fetal bovine serum, mouse fibroblasts, and Matrigel are widely used in the differentiation and culture of hPSC‐RPE cells. Recently, some protocols utilizing human feeders in the culture of pluripotent cells and small molecules in the differentiation process have been published. In our studies, we have also successfully differentiated pigmented cells from hPSC lines without the use of animal cells or serum. These cells show characteristics of RPE cells such as morphology, polarity, expression of genes and proteins typical for RPE cells, and phagocytosis of photoreceptor outer segments.

Conclusion Tissue engineering holds a great promise for treating retinal degenerative diseases. To date, RPE‐like cells have been successfully produced from hPSCs and lately the protocols have been developed further towards xeno‐free and defined culture systems enabling clinical grade cell production.
Birdshot chorioretinopathy: why is sustained immunosuppression going to be the standard of therapy in most cases
Authors: PAPADIA M
Published: December 2011

Abstract not provided
Location of visual field defect and optic disc assessment by confocal scanning laser ophthalmoscope in early normal tension glaucoma
Authors: JUNG KI , PARK CK
Published: December 2011

Purpose To compare topographic optic disc measurements in patients with central 10‐degree and outer arcuate visual field (VF) defects in early normal tension glaucoma (NTG)

Methods Early NTG patients with a mean deviation of ‐10 dB or better in 24‐2 Humphrey VF analyzer, and glaucomatous optic disc were included in this retrospective study. Patients were divided into central VF defect group (CFD) with VF defect in 10‐degree radius in total deviation plot and peripheral VF defect group (PFD) with outer arcuate VF defect. Global and sectoral optic disc stereometric parameters were obtained with the Heidelberg Retina Tomograph (HRT) III and compared between CFD and PFD group. Mean deviation (MD) of central and nasal peripheral 12 points in mean deviation plot compared between superior and inferior hemifields in both groups.

Results Mean deviation and pattern standard deviation values showed no significant difference between 27 patients in the CFD group and 29 patients in the PFD group. The cup area, cup disc area ratio was significantly decreased in CFD group compared to PFD group only in inferotemporal sector, not in other sectoral parameters and global parameters of HRT. The MD of VF in the CFD group was significantly decreased in superior central 6 points (‐9.23±8.12 dB) compared to inferior central 6 points (‐3.36±4.18 dB). The MD of VF in the PFD group showed no significant difference between superior (‐5.24±6.06 dB) and inferior (‐8.10±6.42 dB) nasal peripheral 6 points.

Conclusion The change of optic disc in early NTG was more localized in the CFD group than the PFD group and central VF defect was more prominent in the superior hemifield.
Increased hydrostatic pressure does not cause loss of retinal ganglion cell viability in human organotypic retinal cultures
Authors: SANDERSON J , RHODES J , OSBORNE A , BROADWAY D
Published: December 2011

Purpose Raised intraocular pressure is the major risk factor for glaucoma. It is therefore vitally important to understand how increased pressure impacts on retinal ganglion cells (RGC) viability. These experiments investigate the effect of “pure” hydrostatic pressure on RGC survival in human organotypic retinal cultures (HORCs).

Methods In order to achieve this, we have designed and built a highly sophisticated controlled environment pressure chamber to expose cells to increased hydrostatic pressure while maintaining constancy of other parameters.

Results Exposure of HORCs to constant (60mmHg) or fluctuating (0‐100 mmHg; 1 cycle/min) pressure for 24 or 48h resulted in no loss of structural integrity compared to controls (n=4). No significant changes in levels of RGC markers (THY‐1 mRNA or NeuN) or LDH release were observed (n=4; p>0.05). RGC‐5 cells, used for comparison, showed no change in cell viability (MTS; n=4), LDH release (n=3) or apoptosis (TUNEL; n=3) with pressure at 24 or 72h (p>0.05). Oxygen/glucose deprivation in HORCs reduced RGC number (~40%) at 24h (n=9; p<0.05) and increased LDH release (~80%; n=10; p<0.05). p38 and JNK activation remained unchanged in HORCs exposed to pressure (n=3; p>0.05) whereas OGD increased activation of both (n=3; p<0.05).

Conclusion These data clearly show that increased hydrostatic pressure on its own is insufficient to cause loss of cell viability, suggesting that direct hydrostatic pressure is not responsible for degeneration of RGCs occurring in glaucoma.
Closed angle glaucoma and myopia as an adverse effect of topiramate
Authors: SATUE M , HERRERO LATORRE R , DE LA MATA G , FERNANDEZ‐PEREZ S , GARCIA MARTIN E , POLO V
Published: December 2011

Purpose To present a case report of a patient under topiramate treatment for a depression syndrome, with bilateral acute and closed angle glaucoma as drug adverse effects

Methods Thirty‐seven‐year‐old male developed bilateral severe blurred vision. Exploration showed bilateral acute myopia and closed anterior chambers. Intraocular pressures were 48 mmHg in both eyes, with shallow anterior chambers, and closed angles. His refraction was ‐6.25 diopters in right eye, and ‐8,50 in left eye. During ophthalmic exploration he developed eye pain and corneal edema.

Results All symptoms and clinical findings, including myopia and pain, resolved completely upon discontinuation of topiramate and administration of antiglaucoma drugs.

Conclusion Topiramate may cause acute bilateral angle‐closure glaucoma , so blurry vision, eye pain or altered image perception in treated subjects should be carefully explored by an ophthalmologist. Acute angle closure may result in important intraocular pressure elevation and irreversible optic nerve damage, causing permanent visual loss; so treatment must be withdrawn immediately when alarm symptoms appear.
Endothelin‐ 1 (ET‐1) plasma levels in multiple sclerosis (MS) patients
Authors: JANKOWSKA‐LECH I , BIK Z , WOLINSKA E , TERELAK‐BORYS B , GRABSKA‐LIBEREK I , PALASIK W
Published: December 2011

Purpose The aim of this study was to estimate endothelin‐ 1 (ET‐1) plasma level in multiple sclerosis patients.

Methods Material was 49 patients (13 males, 36 females, mean age: 40 year, range: 22‐ 62 years) suffering from multiple sclerosis according to McDonalds rule. The healthy controls consisted of 3 males and 28 females (mean age: 38 year, range: 19‐ 61 years). The protocol was approved by the Ethical Committee of the Postgraduate Medical Education Centre in Warsaw, Poland. Endothelin‐ 1 (ET‐1) plasma levels were determined by ELISA Test (Immuno‐ Biological Laboratories. Co, Japan with tenderness : 8 fmol/ml). Statistical analysis were performed using the U‐ Mann‐ Withney test.

Results Endothelin‐ 1 (ET‐1) plasma levels were significantly decreased in MS patients when compared to age matched controls (P= 0.0075).

Conclusion Statistically significant ET‐1 plasma levels difference between examined patients and controls indicates, that vascular dysregulation may exists in MS patients. The outcomes will be discussed.
Relationship of intraocular pressure with risk factors of metabolic syndrome
Authors: LEE SU , LEE SJ , LEE JE , LEE JS
Published: December 2011

Purpose To evaluate the relationship of intraocular pressure with risk factors of metabolic syndrome in healthy Korean population

Methods A total of 30893 healthy participants underwent automated multi‐phasic test including tonometry, fundus photography, body mass index measurement and metabolic syndrome risk variables such as systolic and diastolic blood pressure, total cholesterol, high density lipoprotein, triglyceride and fasting blood glucose. The subjects were divided into six age groups by decades ranging from 20∼29 years to over 70 years. The relationship between IOP and metabolic syndrome risk variables was examined using multiple regression analysis.

Results The mean IOP was 15.5±3.2 mmHg, and was significantly higher in men than in women at 20‐69 years aged groups(p<0.05). IOP was associated with systolic and diastolic blood pressure, total cholesterol, triglyceride, body mass index and fasting blood glucose(p<0.05). Systolic and diastolic blood pressure, total cholesterol, triglyceride and fasting blood glucose values had significantly positive relation with IOP (p<0.05), and high density lipoprotein had significantly negative relation. In analysis, intraocular pressure had significant relation with age, gender, systolic and diastolic blood pressure, total cholesterol, triglyceride and fasting blood glucose, but there was no significant relation with body mass index and high density lipoprotein(p>0.05).

Conclusion As increased IOP was associated with metabolic syndrome risk variables, it is necessary to control increased total cholesterol, triglyceride, and blood glucose levels in the normal population to prevent or control the IOP elevation.
The relationship between corneal biomechanical properties and intraocular pressure
Authors: OGBUEHI K , ALMUBRAD T
Published: December 2011

Purpose To determine the relationship between the biomechanical properties and the intraocular pressure (IOP) measured with the Goldmann applanation Tonometer (GAT) and a noncontact tonometer (NCT). Repeatability of corneal biomechanical properties was also assessed.

Methods One randomly selected eye of 106 healthy subjects was assessed using the Ocular Response Analyzer (ORA), a noncontact tonometer, an ultrasound pachymeter and the Goldmann tonometer, on two separate days. The order of measurement was randomized between the ORA and the NCT, followed by measurements of central corneal thickness (CCT) and IOP with the GAT. The main outcome measures were corneal hysteresis (CH), corneal resistance factor (CRF), central corneal thickness (CCT) & IOP.

Results The Pearson correlation coefficients between the GAT IOP on one hand and CH, CRF & CCT on the other, respectively, were: 0.323(P < 0.0001), 0.579 (p < 0.0001), & 0.421 (P < 0.0001) in session 1. The corresponding values for the NCT were: 0.565 (P < 0.0001), 0.772 (P < 0.0001) & 0.681 (P < 0.0001) respectively. The highest correlation coefficients obtained (with both tonometers) when IOP was plot against ‘CCT + CRF’, were: 0.562 (P<0.001) and 0.788 (P<0.0001), for the GAT and the NCT, respectively in session 1. Repeatability indices in the first session were ±2.91mmHg, ±2.51mmHg, and ±0.01μm, respectively, for CH, CRF, & CCT. Reproducibility indices were ±3.11mmHg, ±2.78mmHg and ±0.03μm for CH, CRF and CCT, respectively.

Conclusion CH, CRF, and CCT are all significantly correlated with IOP, more so when the IOP is measured with a NCT. When plot together, CCT &CRF were best able to explain the variation of IOP. All three corneal biomechanical properties showed good repeatability and reproducibility indices.
Characterization of neuroepithelial progenitor cells in patients with proliferative vitreoretinopathy
Authors: MOE MC , JOHNSEN EO , FROEN R , ALBERT R , BERTA A , PETROVSKI G , NICOLAISSEN B
Published: December 2011

Purpose Proliferative vitreoretinopathy (PVR) is an important cause of retinal diseases such as retinal detachment (RD). In lower vertebrates, retinal damage is known to activate neuroepithelial stem cells (NSCs) in the ciliary margin in an attempt to regenerate the neuroretina. Cells expressing some markers of NSCs are also present in the retina and the ciliary body epithelium (CB) of the adult human eye. We hypothesized that if NSCs exist in the adult human eye, they should be activated by PVR formation.

Methods Cells isolated from vitreous samples (n=25) obtained during vitrectomies for RD were directly fixed or cultured in a stem cell‐promoting medium, and compared to cells isolated from post mortem CB and peripheral retina (PR) using sphere‐forming assay, immunohistochemistry, molecular biology and electron microscopy. Markers of NSCs were also studied in whole retinal control/PVR sections obtained from enucleations.

Results Spheres formed in 7/10 vitreous samples from patients with PVR compared to 2/15 samples from patients with no known PVR. These spheres stained for markers of NSCs both in vivo and after repetitive passages. Their mRNA and immunohistochemical profile resembled sphere‐forming cells from the PR with only a few characteristics of CB cells. In situ characterization of the CB revealed that although there were higher numbers of dividing cells in PVR eyes than in controls, we did not detect markers of NSCs. Interestingly, markers of NSCs were evident around PR cysts with some evidence of activation following PVR formation.

Conclusion A population of NSC‐like cells are found in the vitreous of patients with PVR. These cells seem to be originated from the retina itself and not the CB.
Transferrin and prealbumin: indicators of PVR and risk of recurrence in retinal detachment
Authors: ARNDT C , RAMONT L , DUCASSE ALAIN , BONNAY G
Published: December 2011

Purpose Proliferative vitreoretinopathy (PVR) is the leading cause of failure in retinal detachment surgery. Increased levels of transferrine have been found in proliferative vitreoretinopathy. A relationship between the level of prealbumin and the functional outcome has been previously reported. The purpose of this prospective study was to look for a link between the vitreous levels and preoperative PVR or post‐operative outcome.

Methods The vitreous samples of patients with epiretinal membrane and rhegmatogenous retinal detachment (RD) were obtained at the initial phase of surgery without previous intraocular infusion. The levels of transferrine (TF) and prealbumin (PA) were determined in all cases. The functional (visual acuity) and anatomical outcome (OCT mean foveal thickness, RD recurrence) was assessed.

Results The vitreous levels of TF (193 mg/l vs. 44mg/l; p=0.038) and PA(115 mg/l vs. 15mg/l; p=0.0002) were significantly higher in the RD group(n=23) than in the macular surgery group(n=35). In eyes with RD, the intravitreal levels of TF in eyes with PVR A and B were higher than in eyes with PVR C (121 mg/l vs.356 mg/l; p=0,0233). In eyes with PA > 200 mg/l, 2 cases of RD recurrence were observed, when PA < 200 mg, no recurrence was observed (p=0.0296).

Conclusion Increased prealbumin levels in the vitreous appear to correlate with an increased recurrence rate of retinal detachment. The predictive value of prealbumin for the occurrence of postoperative proliferative vitreoretinopathy in patients undergoing retinal detachment surgery remains to be demonstrated and requires a prospective multicenter study.
Acute intraocular pressure after intravitreal injections, what is the mecanism?
Authors: DOT C , EL CHEHAB H , LE CORRE A , RACT‐MADOUX G , COSTE O , SALVANY P , MOURGUES G , SWALDUZ B , GIRAUD JM
Published: December 2011

Purpose To evaluate the mechanism of acute intraocular hypertension after intravitreal injections (IVI) of anti‐VEGF therapies.

Methods A prospective study was performed to evaluate the IOP increase immediately after IVI of 0,05ml ranibizumab in 50 patients. We have also studied the correlation between IOP immediately after IVI and axial length, then with lens status. Moreover we have analysed the anterior chamber anatomic changes (anterior chamber volume and irido corneal angle), measures were taken before and 5mn after IVI by scheimpflug camera from Oculyzer® (Alcon).

Results The IOP peak immediately after IVI was higher than 45 mmHg in 67,3% of patients. It was transient, decreasing after 15mn and returning to baseline in all patient after 45 mn. We found no statistically significant difference between pseudophakic eyes (n=30) and phakic eyes (n=20, p=0.80). No correlation was found between the axial length and the IOP spike (r=0.042, p=0,85). The mean change for the anterior chamber volume (ACV) is mild (0,33 mm3).The ACV increased in pseudophakic eyes (+15,64 mm3, +7,7%), but decreased in the phakic eyes (‐7,24 mm3, ‐4,4%). The mean change for irido corneal angle (ICA) is not significant (‐1,61°), it decreases in phakic eyes (‐2,97°, ‐7,2%) versus a quite neutral effect in pseudophakic eyes (+0,78°, + 1,5%).

Conclusion The IOP spike is not correlated either with axial lengh or with lens status. ACV and ICA variations are different according to the lens status but remains mild. These results enhance the importance of the scleral biomechanical properties, and highlight an unpredictable peak. This could be an argument to propose a systematic prophylactic hypotensive treatment before IVI.