Heterochromatic Flicker Electroretinograms Reflecting Luminance and Cone Opponent Activity in Glaucoma Patients

PURPOSE. To measure heterochromatic flicker electroretinograms (ERGs) at high (36 Hz) and intermediate (12 Hz) temporal frequencies to evaluate luminance and cone opponent responses, respectively, in glaucoma eyes with (perimetric) and without (preperimetric) visual field defects. METHODS. Flicker ERGs were recorded from one randomly chosen dilated eye of 32 patients (mean age, 61 +/- 11 years; 15 men, 17 women) from the Erlangen Glaucoma Registry and from 24 healthy volunteers (mean age, 43 +/- 11 years; 14 men, 10 women). Red and green light-emitting diodes in a Ganzfeld stimulator were sine wave-modulated in counterphase. The responses were measured at 36 Hz, the frequency at which ERGs reflect activity of the luminance pathway, and at 12 Hz, the frequency at which ERGs reflect chromatic activity. RESULTS. Response amplitudes were similar in glaucoma patients and controls. Phase differences were observed in patients with visual field defects (perimetric) compared with the control group at 36 and 12 Hz in the first harmonic and second harmonic responses. Patients without visual field defects (preperimetric) showed phase differences for the second harmonic component at 36 Hz. No age effect on response amplitudes and phases was found in any of the subject groups (controls and patients). CONCLUSIONS. The responses displayed phase differences but not amplitude differences in perimetric glaucoma patients at both 36 and 12 Hz, suggesting that both magnocellular and parvocellular pathways are affected. Preperimetric glaucoma patients also showed phase differences. The response phase may be sensitive to early dysfunction of the inner retina. (ClinicalTrials.gov number, NCT00494923.) (Invest Ophthalmol Vis Sci. 2011;52:6757-6765) DOI:10.1167/iovs.11-7538

Thyroid hormone action is required for normal cone opsin expression during mouse retinal development

PURPOSE. The expression of S- and M-opsins in the murine retina is altered in different transgenic mouse models with mutations in the thyroid hormone receptor (TR)-beta gene, demonstrating an important role of thyroid hormone (TH) in retinal development. METHODS. The spatial expression of S- and M-opsin was compared in congenital hypothyroidism and in two different TR mutant mouse models. One mouse model contains a ligand-binding mutation that abolishes TH binding and results in constitutive binding to nuclear corepressors. The second model contains a mutation that blocks binding of coactivators to the AF-2 domain without affecting TH binding. RESULTS. Hypothyroid newborn mice showed an increase in S- opsin expression that was completely independent of the genotype. Concerning M-opsin expression, hypothyroidism caused a significant decrease (P < 0.01) only in wild-type animals. When TR beta 1 and -beta 2 were T3-binding defective, the pattern of opsin expression was similar to TR beta ablation, showing increased S- opsin expression in the dorsal retina and no expression of M-opsin in the entire retina. In an unexpected finding, immunostaining for both opsins was detected when both subtypes of TR beta were mutated in the helix 12 AF-2 domain. CONCLUSIONS. The results show, for the first time, that the expression of S- and M-opsin is dependent on normal thyroid hormone levels during development.

Toward a Clinical Protocol for Assessing Rod, Cone, and Melanopsin Contributions to the Human Pupil Response

PURPOSE. To better understand the relative contributions of rod, cone, and melanopsin to the human pupillary light reflex (PLR) and to determine the optimal conditions for assessing the health of the rod, cone, and melanopsin pathways with a relatively brief clinical protocol. METHODS. PLR was measured with an eye tracker, and stimuli were controlled with a Ganzfeld system. In experiment 1, 2.5 log cd/m(2) red (640 +/- 10 nm) and blue (467 +/- 17 nm) stimuli of various durations were presented after dark adaptation. In experiments 2 and 3, 1-second red and blue stimuli were presented at different intensity levels in the dark (experiment 2) or on a 0.78 log cd/m(2) blue background (experiment 3). Based on the results of experiments 1 to 3, a clinical protocol was designed and tested on healthy control subjects and patients with retinitis pigmentosa and Leber`s congenital amaurosis. RESULTS. The duration for producing the optimal melanopsin-driven sustained pupil response after termination of an intense blue stimulus was 1 second. PLR rod-and melanopsin-driven components are best studied with low-and high-intensity flashes, respectively, presented in the dark (experiment 2). A blue background suppressed rod and melanopsin responses, making it easy to assess the cone contribution with a red flash (experiment 3). With the clinical protocol, robust melanopsin responses could be seen in patients with few or no contributions from the rods and cones. CONCLUSIONS. It is possible to assess the rod, cone, and melanopsin contributions to the PLR with blue flashes at two or three intensity levels in the dark and one red flash on a blue background. (Invest Ophthalmol Vis Sci. 2011; 52: 6624-6635) DOI: 10.1167/iovs.11-7586

Contrast Sensitivity Mediated by Inferred Magno- and Parvocellular Pathways in Type 2 Diabetics with and without Nonproliferative Retinopathy

PURPOSE. To evaluate achromatic contrast sensitivity (CS) with magnocellular-(M) and parvocellular-(P) probing stimuli in type 2 diabetics, with (DR) or without (NDR) nonproliferative retinopathy. METHODS. Inferred M-and P-dominated responses were assessed with a modified version of the steady-/pulsed-pedestal paradigm (SP/PP) applied in 26 NDR (11 male; mean age, 55 +/- 9 years; disease duration, 5 +/- 4 years); 19 DR (6 male; mean age, 58 +/- 7 years; disease duration = 9 +/- 6 years); and 18 controls (CTRL; 12 male; mean age, 55 +/- 10 years). Thresholds were measured with pedestals at 7, 12, and 19 cd/m(2), and increment durations of 17 and 133 ms. The thresholds from the two stimulus durations were used to estimate critical durations (Tc) for each data set. RESULTS. Both DR and NDR patients had significant reduction in CS in both SP and PP paradigms in relation to CTRL (Kruskal-Wallis, P < 0.01). Patients` critical duration estimates for either paradigm were not significantly different from CTRL. CONCLUSIONS. The significant reduction of CS in both paradigms is consistent with losses of CS in both M and P pathways. The CS losses were not accompanied by losses in temporal processing speed in either diabetic group. Significant CS loss in the group without retinopathy reinforces the notion that neural changes associated with the cellular and functional visual loss may play an important role in the etiology of diabetic visual impairment. In addition, the results show that the SP/PP paradigm provides an additional tool for detection and characterization of the early functional damage due to diabetes. (Invest Ophthalmol Vis Sci. 2011; 52:1151-1155) DOI:10.1167/iovs.09-3705

Phosphene Thresholds Elicited by Transcorneal Electrical Stimulation in Healthy Subjects and Patients with Retinal Diseases

PURPOSE. To evaluate electrically evoked phosphene thresholds (EPTs) in healthy subjects and in patients with retinal disease and to assess repeatability and possible correlations with common ophthalmologic tests. METHODS. In all, 117 individuals participated: healthy subjects (n = 20) and patients with retinitis pigmentosa (RP, n = 30), Stargardt's disease (STG, n = 14), retinal artery occlusion (RAO, n = 20), nonarteritic anterior ischemic optic neuropathy (NAION, n = 16), and primary open-angle glaucoma (POAG, n = 17). EPTs were determined at 3, 6, 9, 20, 40, 60, and 80 Hz with 5+5-ms biphasic current pulses using DTL electrodes. Subjects were examined twice (test-retest range: 1-6 weeks). An empirical model was developed to describe the current-frequency relationship of EPTs. Visual acuity, visual field (kinetic + static), electrophysiology (RP, RAO, STG: Ganzfeld-electroretinography [ERG]/multifocal-ERG; POAG: pattern-ERG; NAION: VEP), slit-lamp biomicroscopy, fundus examination, and tonometry were assessed. RESULTS. EPTs varied between disease groups (20 Hz: healthy subjects: 0.062 +/- 0.038 mA; STG: 0.102 +/- 0.097 mA; POAG: 0.127 +/- 0.09 mA; NAION: 0.244 +/- 0.126 mA; RP: 0.371 +/- 0.223 mA; RAO: 0.988 +/- 1.142 mA). In all groups EPTs were lowest at 20 Hz. In patients with retinal diseases and across all frequencies EPTs were significantly higher than those in healthy subjects, except in STG at 20 Hz (P = 0.09) and 40 Hz (P = 0.17). Test-retest difference at 20 Hz was 0.006 mA in the healthy group and 0.003-0.04 mA in disease groups. CONCLUSIONS. Considering the fast, safe, and reliable practicability of EPT testing, this test might be used more often under clinical circumstances. Determination of EPTs could be potentially useful in elucidation of the progress of ophthalmologic diseases, either in addition to standard clinical assessment or under conditions in which these standard tests cannot be used meaningfully. (ClinicalTrials.gov number, NCT00804102.) (Invest Ophthalmol Vis Sci. 2012; 53: 7440-7448) DOI:10.1167/iovs.12-9612

Laminar Displacement and Prelaminar Tissue Thickness Change after Glaucoma Surgery Imaged with Optical Coherence Tomography

PURPOSE. To study changes in lamina cribrosa position and prelaminar tissue thickness (PTT) after surgical IOP reduction in glaucoma patients. METHODS. Twenty-two patients (mean age, 71.4 years) were imaged with spectral domain optical coherence tomography (SD-OCT; 24 radial B-scans centered on the optic nerve head [ONH]) before trabeculectomy or tube shunt implantation. Follow up images were acquired 1 week, 1 month, 3 months, and 6 months postsurgery. Bruch's membrane opening (BMO), the internal limiting membrane (ILM) and the anterior laminar surface (ALS) were segmented in each radial scan with custom software. Surfaces were fitted to the ILM and ALS with the extracted three-dimesional coordinates. PTT was the distance between the ILM and ALS, perpendicular to a BMO reference plane. Serial postsurgical laminar displacement (LD), relative to the BMO reference plane, and changes in PTT were measured. Positive values indicated anterior LD. RESULTS. Mean (SD) presurgery IOP was 18.1 (6.5) mm Hg, and reduced by 4.7 (5.5), 2.4 (7.7), 7.0 (6.2), and 6.8 (7.5) mm Hg at 1 week, 1 month, 3 months, and 6 months postsurgery, respectively. At the four postsurgery time points, there was significant anterior LD (1.8 [9.5], -1.1 [8.9], 8.8 [20.2], and 17.9 [25.8] mu m) and PTT increase (1.7 [13.3], 2.4 [11.9], 17.4 [13.7], and 13.9 [18.6] mu m). LD was greater in ONHs with larger BMO area (P = 0.01) and deeper ALS (P = 0.04); however, PTT was not associated with any of the tested independent variables. CONCLUSIONS. Both anterior LD and thickening of prelaminar tissue occur after surgical IOP reduction in patients with glaucoma. (Invest Ophthalmol Vis Sci. 2012;53:5819-5826) DOI:10.1167/iovs.12-9924

Transcorneal Electrical Stimulation Shows Neuroprotective Effects in Retinas of Light-Exposed Rats

PURPOSE. To examine the effects of transcorneal electrical stimulation (TES) on retinal degeneration of light-exposed rats. METHODS. Thirty-three Sprague Dawley albino rats were divided into three groups: STIM (n = 15) received 60 minutes of TES, whereas SHAM (n = 15) received identical sham stimulation 2 hours before exposure to bright light with 16,000 lux; healthy animals (n = 3) served as controls for histology. At baseline and weekly for 3 consecutive weeks, dark-and light-adapted electroretinography was used to assess retinal function. Analysis of the response versus luminance function retrieved the parameters Vmax (saturation amplitude) and k (luminance to reach 1/2Vmax). Retinal morphology was assessed by histology (hematoxylin-eosin [HE] staining; TUNEL assay) and immunohistochemistry (rhodopsin staining). RESULTS. Vmax was higher in the STIM group compared with SHAM 1 week after light damage (mean intra-individual difference between groups 116.06 mu V; P = 0.046). The b-wave implicit time for the rod response (0.01 cd.s/m(2)) was lower in the STIM group compared with the SHAM group 2 weeks after light damage (mean intra-individual difference between groups 5.78 ms; P = 0.023); no other significant differences were found. Histological analyses showed photoreceptor cell death (TUNEL and HE) in SHAM, most pronounced in the superior hemiretina. STIM showed complete outer nuclear layer thickness preservation, reduced photoreceptor cell death, and preserved outer segment length compared with SHAM (HE and rhodopsin). CONCLUSIONS. This sham-controlled study shows that TES can protect retinal cells against mild light-induced degeneration in Sprague Dawley rats. These findings could help to establish TES as a treatment in human forms of retinal degenerative disease. (Invest Ophthalmol Vis Sci. 2012;53:5552-5561) DOI: 10.1167/iovs.12-10037

Quantification of Retinal Neural Loss in Patients with Neuromyelitis Optica and Multiple Sclerosis with or without Optic Neuritis Using Fourier-Domain Optical Coherence Tomography

PURPOSE. We compared retinal nerve fiber layer (RNFL) and macular thickness measurements in patients with multiple sclerosis (MS) and neuromyelitis optica (NMO) with or without a history of optic neuritis, and in controls using Fourier-domain (FD) optical coherence tomography (OCT). METHODS. Patients with MS (n = 60), NMO (n = 33), longitudinal extensive transverse myelitis (LETM, n = 28) and healthy controls (n = 41) underwent ophthalmic examination, including automated perimetry, and FD-OCT RNFL and macular thickness measurements. Five groups of eyes were compared: MS with or without previous optic neuritis, NMO, LETM, and controls. Correlation between OCT and visual field (VF) findings was investigated. RESULTS. With regard to most parameters, RNFL and macular thickness measurements were significantly smaller in eyes of each group of patients compared to controls. MS eyes with optic neuritis did not differ significantly from MS eyes without optic neuritis, but measurements were smaller in NMO eyes than in all other groups. RNFL (but not macular thickness) measurements were significantly smaller in LETM eyes than in controls. While OCT abnormalities were correlated significantly with VF loss in NMO/LETM and MS, the correlation was much stronger in the former. CONCLUSIONS. Although FD-OCT RNFL and macular thickness measurements can reveal subclinical or optic neuritis-related abnormalities in NMO-spectrum and MS patients, abnormalities are predominant in the macula of MS patients and in RFNL measurements in NMO patients. The correlation between OCT and VF abnormalities was stronger in NMO than in MS, suggesting the two conditions differ regarding structural and functional damage. (ClinicalTrials.gov number, NCT01024985.) Invest Ophthalmol Vis Sci. 2012;53:3959-3966) DOI:10.1167/iovs.11-9324

Influence of Clinically Invisible, but Optical Coherence Tomography Detected, Optic Disc Margin Anatomy on Neuroretinal Rim Evaluation

PURPOSE. We previously demonstrated that most eyes have regionally variable extensions of Bruch's membrane (BM) inside the clinically identified disc margin (DM) that are clinically and photographically invisible. We studied the impact of these findings on DM- and BM opening (BMO)-derived neuroretinal rim parameters. METHODS. Disc stereo-photography and spectral domain optical coherence tomography (SD-OCT, 24 radial B-scans centered on the optic nerve head) were performed on 30 glaucoma patients and 10 age-matched controls. Photographs were colocalized to SD-OCT data such that the DM and BMO could be visualized in each B-scan. Three parameters were computed: (1) DM-horizontal rim width (HRW), the distance between the DM and internal limiting membrane (ILM) along the DM reference plane; (2) BMO-HRW, the distance between BMO and ILM along the BMO reference plane; and (3) BMO-minimum rim width (MRW), the minimum distance between BMO and ILM. Rank-order correlations of sectors ranked by rim width and spatial concordance measured as angular distances between equivalently ranked sectors were derived. RESULTS. The average DM position was external to BMO in all quadrants, except inferotemporally. There were significant sectoral differences among all three rim parameters. DM- HRW and BMO-HRW sector ranks were better correlated (median rho = 0.84) than DM- HRW and BMO-MRW (median rho = 0.55), or BMO-HRW and BMO-MRW (median rho = 0.60) ranks. Sectors with the narrowest BMO-MRW were infrequently the same as those with the narrowest DM-HRW or BMO-HRW. CONCLUSIONS. BMO-MRW quantifies the neuroretinal rim from a true anatomical outer border and accounts for its variable trajectory at the point of measurement. (Invest Ophthalmol Vis Sci. 2012;53:1852-1860) DOI:10.1167/iovs.11-9309

IgG Autoantibody Response against Keratinocyte Cadherins in Endemic Pemphigus Foliaceus (Fogo Selvagem)

It is well established that autoantibodies against desmoglein 3 and desmoglein 1 (Dsg1) are relevant in the pathogenesis of pemphigus vulgaris and pemphigus foliaceus, including its endemic form fogo selvagem (FS). Isolated reports have shown that in certain patients with these diseases, autoantibodies against other desmosomal cadherins and E-cadherin may also be present. The goal of this investigation was to determine whether FS patients and normal individuals living in endemic areas possess autoantibodies against other desmosomal cadherins and E-cadherin. By testing a large number of FS and endemic control sera by ELISA, we found a consistent and specific autoantibody response against Dsg1 and other keratinocyte cadherins in these individuals, which is quite different from healthy individuals from the United States (US controls). Overall, the highest correlations among the autoantibody responses tested were in the endemic controls, followed by FS patients, and lowest in the US controls. These findings suggest that multiple, perhaps cross-reactive, keratinocyte cadherins are recognized by FS patients and endemic controls.

Protective Effect of Human Endogenous Retrovirus K dUTPase Variants on Psoriasis Susceptibility

Previous genetic and functional studies have implicated the human endogenous retrovirus K (HERV-K) dUTPase located within the PSORS1 locus in the major histocompatibility complex region as a candidate psoriasis gene. Here, we describe a variant discovery and case-control association study of HERV-K dUTPase variants in 708 psoriasis cases and 349 healthy controls. Five common HERV-K dUTPase variants were found to be highly associated with psoriasis, with the strongest association occurring at the missense single-nucleotide polymorphism (SNP) rs3134774 (K158R, P=3.28 x 10(-15), odds ratio = 2.36 (95% confidence interval: 1.91-2.92)). After adjusting the association of the HERV-K dUTPase variants for the potential confounding effects of HLA alleles associated with psoriasis, the HERV-K SNPs rs9264082 and rs3134774 remained significantly associated. Haplotype analysis revealed that HERV-K haplotypes containing the non-risk alleles for rs3134774 and rs9264082 significantly reduced the risk of psoriasis. Functional testing showed higher antibody responses against recombinant HERV-K dUTPase in psoriasis patients compared with controls (P<0.05), as well as higher T-cell responses against a single HERV-K dUTPase peptide (P<0.05). Our data support an independent role for the HERV-K dUTPase on psoriasis susceptibility, and suggest the need for additional studies to clarify the role of this dUTPase in the pathogenesis of psoriasis. Journal of Investigative Dermatology (2012) 132, 1833-1840; doi:10.1038/jid.2012.69; published online 22 March 2012

Oral Administration of Oleic or Linoleic Acid Accelerates the Inflammatory Phase of Wound Healing

The effects of oral ingestion of oleic (OLA) and linoleic (LNA) acids on wound healing in rats were investigated. LNA increased the influx of inflammatory cells, the concentration of hydrogen peroxide (H(2)O(2)) and cytokine-induced neutrophil chemoattractant-2 alpha beta (CINC-2 alpha beta), and the activation of the transcription factor activator protein-1 (AP-1) in the wound at 1 hour post wounding. LNA decreased the number of inflammatory cells and IL-1, IL-6, and macrophage inflammatory protein-3 (MIP-3) concentrations, as well as NF-kappa B activation in the wound at 24 hours post wounding. LNA accelerated wound closure over a period of 7 days. OLA increased TNF-alpha concentration and NF-kappa B activation at 1 hour post wounding. A reduction of IL-1, IL-6, and MIP-3 alpha concentrations, as well as NF-kappa B activation, was observed 24 hours post wounding in the OLA group. These data suggest that OLA and LNA accelerate the inflammatory phase of wound healing, but that they achieve this through different mechanisms.

In Vitro Effects of Bevacizumab Treatment on Newborn Rat Retinal Cell Proliferation, Death, and Differentiation

PURPOSE. Vascular endothelial growth factor (VEGF) is an important signal protein in vertebrate nervous development, promoting neurogenesis, neuronal patterning, and glial cell growth. Bevacizumab, an anti-VEGF agent, has been extensively used for controlling pathological retinal neovascularization in adult and newborn patients, although its effect on the developing retina remains largely unknown. The purpose of this study was to investigate the effect of bevacizumab on cell death, proliferation, and differentiation in newborn rat retina. METHODS. Retinal explants of sixty 2-day-old Lister hooded rats were obtained after eye enucleation and maintained in culture media with or without bevacizumab for 2 days. Immunohistochemical staining was assessed against proliferating cell nuclear antigen (PCNA, to detect cell proliferation); caspase-3 and beclin-1 (to investigate cell death); and vimentin and glial fibrillary acidic protein (GFAP, markers of glial cells). Gene expressions were quantified by real-time reverse-transcription polymerase chain reaction. Results from treatment and control groups were compared. RESULTS. No significant difference in the staining intensity (on immunohistochemistry) of PCNA, caspase-3, beclin-1, and GFAP, or in the levels of PCNA, caspase-3, beclin-1, and vimentin mRNA was observed between the groups. However, a significant increase in vimentin levels and a significant decrease in GFAP mRNA expression were observed in bevacizumab-treated retinal explants compared with controls. CONCLUSIONS. Bevacizumab did not affect cell death or proliferation in early developing rat retina but appeared to interfere with glial cell maturation by increasing vimentin levels and downregulating GFAP gene expression. Thus, we suggest anti-VEGF agents be used with caution in developing retinal tissue. (Invest Ophthalmol Vis Sci. 2012;53:7904-7911) DOI:10.1167/iovs.12-10283

FRBR – REQUISITOS FUNCIONAIS PARA REGISTROS BIBLIOGRÁFICOS: primeiro estudo investigativo da USP

Os FRBR se apresentam como uma nova filosofia na de scrição dos objetos de informação. Como tema recente no cenário biblioteco nômico brasileiro, um grupo de projetos do SIBi-USP propôs um estudo investigat ivo dos aspectos teórico e prático sobre o tema. O método contemplou a pesquis a documental e o levantamento de experiências. Os resultados indicam que a literatura em Português ainda é incipiente, sendo a compreensão d o tema dependente da literatura inglesa. As vantagens da prática do mode lo FRBR parecem ser a forma de exibição das informações ao usuário e a facilida de na catalogação dos registros. Não há relato da prática no Brasil; como conseqüência, não há pesquisas de satisfação de usuários dos FRBR

Factor Xa activation of factor V is of paramount importance in initiating the coagulation system: lessons from a tick salivary protein

BACKGROUND: Generation of active procoagulant cofactor factor Va (FVa) and its subsequent association with the enzyme activated factor X (FXa) to form the prothrombinase complex is a pivotal initial event in blood coagulation and has been the subject of investigative effort, speculation, and controversy. The current paradigm assumes that FV activation is initiated by limited proteolysis by traces of (meizo) thrombin. METHODS AND RESULTS: Recombinant tick salivary protein TIX-5 was produced and anticoagulant properties were studied with the use of plasma, whole blood, and purified systems. Here, we report that TIX-5 specifically inhibits FXa-mediated FV activation involving the B domain of FV and show that FXa activation of FV is pivotal for plasma and blood clotting. Accordingly, tick feeding is impaired on TIX-5 immune rabbits, displaying the in vivo importance of TIX-5. CONCLUSIONS: Our data elucidate a unique molecular mechanism by which ticks inhibit the host's coagulation system. From our data, we propose a revised blood coagulation scheme in which direct FXa-mediated FV activation occurs in the initiation phase during which thrombin-mediated FV activation is restrained by fibrinogen and inhibitors.