Rita Vámos

Association of Genetic Polymorphisms of Vascular Endothelial Growth Factor and Risk for Proliferative Retinopathy of Prematurity

The intention of our retrospective study was to determine whether vascular endothelial growth factor (VEGF) genetic polymorphisms are associated with risk for proliferative retinopathy of prematurity (ROP), a condition that is characterized by abnormal retinal neovascularization and can lead to retinal detachment and result in blindness. We enrolled 86 very low birth weight infants (birth weight ≤1500 g) who had been treated with cryo/laser therapy because of the risk for proliferative ROP (treated group). Their VEGF T−460C and G+405C genotypes were determined from dried blood samples and were compared with VEGF genotypes of 115 VLBW infants who were not treated with cryo/laser therapy (untreated group). We found that the allele frequency of VEGF +405C was higher in the treated group than in the untreated group (0.30 versus 0.41; p < 0.05). The likelihood of being treated for ROP was higher in heterozygous and homozygous carriers of VEGF +405C alleles [odds ratios adjusted for risk factors of ROP (95% CI): 2.00 (1.02–3.92; p = 0.04) and 3.37 (1.17–9.65; p = 0.007), respectively]. VEGF −460TT/+405CC haplotype was more prevalent in the treated patients than in the untreated patients (13 of 86 versus 1 of 115; p < 0.001), and the association remained significant (p < 0.01) even after the adjustment for risk factors of ROP (gestational age, supplemental oxygen therapy, and gender). These findings suggest that the VEGF genotype may be associated with risk for proliferative ROP in VLBW infants.

Mutation Detection in Patients with Retinal Dystrophies Using Targeted Next Generation Sequencing.

Retinal dystrophies (RD) constitute a group of blinding diseases that are characterized by clinical variability and pronounced genetic heterogeneity. The different nonsyndromic and syndromic forms of RD can be attributed to mutations in more than 200 genes. Consequently, next generation sequencing (NGS) technologies are among the most promising approaches to identify mutations in RD. We screened a large cohort of patients comprising 89 independent cases and families with various subforms of RD applying different NGS platforms. While mutation screening in 50 cases was performed using a RD gene capture panel, 47 cases were analyzed using whole exome sequencing. One family was analyzed using whole genome sequencing. A detection rate of 61% was achieved including mutations in 34 known and two novel RD genes. A total of 69 distinct mutations were identified, including 39 novel mutations. Notably, genetic findings in several families were not consistent with the initial clinical diagnosis. Clinical reassessment resulted in refinement of the clinical diagnosis in some of these families and confirmed the broad clinical spectrum associated with mutations in RD genes.

The structure and function of the macula in patients with advanced retinitis pigmentosa.

PURPOSE To assess the structure and function of the macula in advanced retinitis pigmentosa (RP). METHODS Twenty-nine eyes of 22 patients with RP were compared against 17 control eyes. Time-domain optical coherence tomography (OCT) data were processed using OCTRIMA (optical coherence tomography retinal image analysis) as a means of quantifying commercial OCT system images. The thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer and inner plexiform layer complex (GCL+IPL), inner nuclear layer and outer plexiform layer complex (INL+OPL), and the outer nuclear layer (ONL) were measured. Multifocal electroretinography (mfERG) was performed; two groups were formed based on the mfERG findings. Fourteen eyes had no detectable central retinal function (NCRF) on mfERG; detectable but abnormal retinal function (DRF) was present in the mfERG of the other 15 eyes. RESULTS The thickness of the ONL in the central macular region was significantly less in the NCRF eyes compared with that in both DRF eyes and controls. The ONL was significantly thinner in the pericentral region in both patient groups compared with that in controls, whereas the thickness of the GCL+IPL and INL+OPL was significantly decreased only in the NCRF eyes. The RNFL in the peripheral region was significantly thicker, whereas the thickness of the GCL+IPL and ONL was significantly thinner in both patient groups compared with that in controls. CONCLUSIONS The results are consistent with degeneration of the outer retina preceding inner retinal changes in RP. OCT image segmentation enables objective evaluation of retinal structural changes in RP, with potential use in the planning of therapeutic interventions and conceivably as an outcome measure.

Laser Treatment of Zone I Prethreshold and Stage 3 Threshold Retinopathy of Prematurity

PURPOSE To analyze the structural outcomes of zone I prethreshold and stage 3 threshold retinopathy of prematurity following laser ablation. PATIENTS AND METHODS This nonrandomized observational case series evaluated 71 eyes of 36 infants who weighed less than 1,250 g at birth. Infants were treated at either prethreshold or threshold severity. The structural outcomes were compared using Fishers exact test. RESULTS The structural outcome was favorable in 96% and 80% of the prethreshold and threshold groups, respectively (P = .069). When an unfavorable outcome was defined as dragging of the temporal vessels, the difference was significant (P = .0257). CONCLUSION Early treatment of zone I disease may result in a better structural outcome.

Utilization of lacrimal urea assay in the monitoring of hemodialysis: conditions, limitations and lacrimal arginase characterization

The lacrimal urea content was found to be proportional to that of blood, which suggested its possible utilization in the monitoring of hemodialysis as a less invasive method. On the other hand, however, arginase activity was detected in tears, which may influence the urea content independently of blood urea concentration. The feasibility of using lacrimal urea measurement to replace blood urea measurement in the monitoring hemodialysis was also investigated. Blood and tear samples of 35 healthy persons and 43 renal patients undergoing hemodialysis were tested. Tear samples were collected on Schirmer paper strips. After elution the lacrimal urea content was measured by a colorimetric method. The determination of arginase activity was based on the release of urea and ornithine. The correlation between blood and lacrimal urea and arginase was studied by multivariate regression analysis. The lacrimal arginase isoenzyme pattern was investigated by native polyacrylamide gel electrophoresis and Western blotting. The effect of partially isoform-specific inhibitors was also studied. Blood urea levels in blood were significantly higher in the renal patients before dialysis than in the control patients (12.86 +/- 0.59 vs. 6.45 +/- 0.41 mM, p < 0.0001). Blood sera arginase activity was very low. Lacrimal arginase activity was significantly higher in tears than in sera (p < 0.0001 for each group). The tear/serum ratio of urea content was significantly different between controls and renal patients, particularly in postdialytic samples (1.89 +/- 0.07 vs. 3.49 +/- 0.31, p < 0.0001). The correlation between lacrimal and blood sera urea was best in controls (r = 0.89) and was better in predialytic (r = 0.75) than in postdialytic (r = 0.52) samples, depending on the level of arginase activity. In postdialytic samples a stronger correlation (r = 0.77) between tear urea and arginase was observed. Both arginase isoforms were detected in tears, but the extrahepatic (arginase II) isoenzyme was present in higher concentration. In conclusion, the determination of lacrimal urea level as a possible less invasive replacement for blood urea determination could only be utilized in the monitoring of hemodialysis if lacrimal arginase is also measured. Blood urea levels can be correctly determined by using equations, which take into account arginase activity. The accuracy of these equations was checked on a new patient population. Both arginase isoenzymes were observed in lacrimal samples.

The inhibition of retinal inducible nitric oxide synthase overexpression and the attenuation of experimental uveitis by anti-inflammatory drugs in rats

AbstractObjective and design:The effect of a steroid and a non-steroid anti-inflammatory drug on the inducible nitric oxide synthase (NOS II) in rats suffering from lipopolysaccharide (LPS)-induced uveoretinitis was studied. Treatments:Rats were injected with LPS to induce uveitis and divided into three groups: treated with LPS only, LPS + dexamethasone and LPS + indomethacin, respectively. Methods:Retinal, peritoneal macrophages and white blood cells were isolated. The activity and the expression of NOS II were followed by citrulline formation and Western blotting, respectively. Phagocytosis of bacteria was also measured. Results:The best induction of NOS II was achieved by the intravitreal administration of LPS. Dexamethasone and indomethacin significantly decreased the activity and the expression of inducible nitric oxide synthase in retinal tissue, peritoneal macrophages and white blood cells. LPS treatment also increased phagocytosis and neither dexamethasone nor indomethacin reversed this effect. Conclusions:The beneficial effects of these drugs in experimental uveitis are mediated, at least partly, by their inhibitory effect on NOS II induction.

Role of multifocal electroretinography in the diagnosis of idiopathic macular hole.

PURPOSE To analyze the preoperative results of multifocal electroretinography (mfERG) in the fellow eyes of patients with idiopathic unilateral macular hole and to evaluate the usefulness of this method in predicting the likelihood of macular hole formation in the fellow eye. METHODS Over a period of 5 years, 80 eyes of 40 patients (mean age, 64.9 years) with unilateral idiopathic macular hole were examined. The diagnosis of idiopathic macular hole was confirmed by optical coherence tomography (OCT). The fellow eyes were intact in all cases. All patients underwent vitreoretinal surgery. Before the surgery, both eyes of the patients were examined by mfERG. During the follow-up period, the 40 fellow eyes were also observed by OCT, and the changes in the vitreofoveal attachment were investigated. The preoperative response densities and ring ratios of mfERG were analyzed in both eyes, and discriminant analysis was used to calculate the best separator function. RESULTS Preoperative mfERGs demonstrated significantly lower mean response densities in the central area of the 40 eyes with macular hole than in the fellow eyes. During the follow-up period, macular hole was diagnosed in 13 fellow eyes by OCT. The preoperative values of the mfERGs in these eyes were significantly lower than in the other 27 cases. The mfERG ring ratios were significantly lower in the fellow eyes in which macular holes developed than in those that remained intact. CONCLUSIONS The analysis of ERG in the fellow eyes of patients with macular hole seems clinically useful. The lower amplitude may forecast the propensity for subsequent development of a macular hole. Patients with low central ERG amplitude and lower ring ratios in the healthy fellow eyes should have stricter follow-up.

Neuronal migration disorders, agenesis of corpus callosum, preauricular skin tag and bilateral morning glory syndrome in a term newborn infant.

Schizencephaly is a congenital migrational anomaly resulting in a cleft in the cerebral hemisphere. In polymycrogyria, which is also a migrational disorder, the gyri are numerous and small, with proliferation of secondary and tertiary sulci. Agenesis of corpus callosum (partial or complete) is a relatively frequent malformation that can be associated with migrational anomalies and other brain malformations (Whitaker, 1996).

Leber congenital amaurosis: First genotyped Hungarian patients and report of 2 novel mutations in the CRB1 and CEP290 genes

Purpose To introduce the first Hungarian patients with genetically defined Leber congenital amaurosis (LCA) and to report 2 novel mutations. Methods Seven otherwise healthy patients (4-29 years, 5 male and 2 female) who had an onset of severe visual impairment before age 2 years were investigated. The diagnosis was established in all individuals by medical history, funduscopy, and full-field electroretinogram (ERG). Ocular examination included visual acuity testing, digital fundus photography, and in 6 patients retinal imaging with optical coherence tomography (OCT). Arrayed primer extension microarray screening was performed in all probands. In 2 patients, further Sanger sequencing and targeted next-generation sequencing revealed the second disease allele. Results A cone-rod type LCA was revealed in 4 patients and a rod-cone type disease in 3 patients. Five patients presented with maculopathy. Optical coherence tomography (OCT) imaging showed diffuse retinal thickening in 3 probands with severe macular atrophy in one. Full-field ERGs were undetectable or residual in all patients. Genetic screening revealed AIPL1, CRB1, and CEP290 gene-related pathology in 6 patients; in 1 proband, no mutation was found. Three homozygous and 3 compound heterozygous mutations were identified. Two novel variants were detected: c.2536G>T (p.G846X) in the CRB1 gene and c.4929delA (p.Lys1643fsX2) in the CEP290 gene. Conclusions Genetic subtypes identified are among the most common ones in LCA; the phenotypes are consistent with those reported previously. Both novel mutations are predicted to result in a premature translation termination. The phenotype related to the novel CRB1 mutation results in severe atrophic maculopathy.