CD147 and matrix-metalloproteinase-2 expression in metastatic and non-metastatic uveal melanomas.

BACKGROUND: Extracellular matrix remodelling regulated by matrix-metalloproteinase (MMP) inducer (CD147) is a crucial process during tumor cell invasion and regulation of blood supply. In this study, we evaluated the correlation of CD147 and MMP-2 expression with major prognostic factors for uveal melanoma and the development of metastasis. METHODS: The expression of CD147 and MMP-2 was analyzed in 49 samples of uveal melanomas. Triple immunofluorescence stainings using markers against glial cells (GFAP), endothelial cells (CD34) and macrophages (CD68) were performed to further analyse the exact localisation of CD147 and MMP-2 positivity. In 28 cases clinical metastatic disease were found. The remaining 21 cases showed no signs of metastatic disease for an average follow-up of 10 years. Correlation analysis (Pearson correlation) was performed to analyse the association of CD147 and MMP-2 expression with known prognostic factors, vasculogenic mimicry (VM), the mature vasculature (von Willebrand Factor) and tumor induced angiogenesis (by means of Endoglin expression). RESULTS: CD147 and MMP-2 were expressed in 47 (96.0 %) of the uveal melanomas. CD147 up-regulation was significantly correlated with a higher MMP-2 expression. The overall expression analysis revealed no significant difference in the metastatic (p = 0.777) and non-metastatic subgroup (p = 0.585). No correlation of CD147 expression and any system of blood supply was evident. In the non-metastatic sub-group a significant correlation of clustered CD147 positive cells with largest basal diameter (p = 0.039), height (p = 0.047) and TNM-stage (p = 0.013) was evident. CONCLUSIONS: These data may indicate that CD147 regulates MMP-2 expression in uveal melanoma cells.

Analysis of caveolin-1 and phosphoinositol-3 kinase expression in primary uveal melanomas.

BACKGROUND: To evaluate the regulation of blood supply in primary uveal melanomas through caveolin-1 (Cav-1)/phosphoinositol-3 kinase (PI3K). METHODS: The expression of Cav-1 and PI3K was analysed in 51 paraffin sections of metastatic (n = 30) and non-metastastic uveal melanomas (n = 21). Two trained observers quantified Cav-1 and PI3K immunofluorescensce expression by determining intensity of staining and percentage of positive cells. The expression was correlated with known prognostic factors. Besides angiogenesis by means of endoglin expression, the normal vasculature (von Willebrand Factor expression) was evaluated semi-quantitatively. Vasculogenic mimicry (VM) was analysed by CD31/PAS staining. RESULTS: All examined specimens expressed Cav-1 with a mean of 90.34% Cav-1 positive cells (range, 3.23-100%). Metastatic disease was associated with a higher Cav-1 expression. The correlation of Cav-1 with well-established prognostic factors showed a significant association between Cav-1 expression and largest tumour diameter (P = 0.022), tumour node metastasis classification (P = 0.008) and invasion of optic nerve head (P = 0.048). PI3K was expressed by all uveal melanomas with a mean of 87.28% cells showing PI3K expression. A higher level of PI3K was significantly associated with larger height (P = 0.042) and progressed tumour node metastasis stage (P = 0.016). The percentage of PI3K and Cav-1 positive cells were significantly associated (P = 0.034). For PI3K and Cav-1 expression a non-significant association with VM was shown (P = 0.064 and P = 0.072, respectively). No correlation of PI3K or Cav-1 with angiogenesis or mature vasculature was seen (P > 0.05). CONCLUSIONS: Cav-1 expression may be especially up-regulated in larger uveal melanomas. As it was correlated with PI3K expression and VM in this series of uveal melanoma, Cav-1 might induce the formation of VM via the PI3K-signalling cascade.

Effect of different fixative solutions on eyes with experimental proliferative vitreoretinopathy.

The aim of this study was to evaluate the use of different fixatives on the reliability of histopathological changes in a rabbit model of proliferative vitreoretinopathy (PVR). Twenty eyes from 10 rabbits were divided into four groups. The right eyes were used in two experimental groups (each n = 5), and the left, in two control groups (each n = 5). Using a newly developed scleral incision marker, an oblique scleral incision was standardized in the experimental groups, followed by intravitreal injection of 0.4 ml autologous blood and the left for wound repair for four weeks. Eyes were enucleated at four weeks. The groups differed in the type of used fixative solution (formaldehyde 4% vs. 1% buffered formaldehyde and 1.25% glutaraldehyde). The eyes were evaluated for the development of fibrosis, retinal detachment (RD), and processed for histopathology. Fibrous ingrowth of a variable degree was present in the experimental groups originating from the trauma site. Experimental eyes fixed with formaldehyde 4% had RD extension that was greater than that fixed in formaldehyde/glutaraldehyde mixture; however, the difference did not reach statistical significance (P = 0.15). This difference was not fully explained by the fibrosis which developed. In addition, in control groups, formaldehyde 4% induced a fixative-dependent retinal separation that was absent in eyes fixed with formaldehyde/glutaraldehyde mixture (P = 0.03). In conclusion, a mixture of buffered formaldehyde 1% and glutaraldehyde 1.25% combined with standardized scleral incision resulted in consistent pathological changes. A reliable PVR model is a condition sine qua non to evaluate antifibrotic treatment strategies.

Serum cytokines as biomarkers for age-related macular degeneration.

PURPOSE: This study evaluates the potential of serum pro-inflammatory cytokines as AMD biomarkers. METHODS: Serum samples from 30 age-related macular degeneration (AMD) patients and 15 age-matched controls were examined for 16 inflammatory cytokines using multiplex ELISA. Patients were divided into three subgroups (improvement/no change/deterioration during anti-VEGF treatment) by OCT and funduscopy, and correlated to the cytokine levels. RESULTS: Serum concentrations of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 were significantly higher in AMD patients than in controls. None of the co-variables expressed a significant effect on the tested cytokines. Only IL-1a and IL-17 showed a statistically significant difference between groups (improved, unchanged, deteriorated) as determined by one-way ANOVA. Patients with increased macular thickness during treatment showed significantly lower levels of IL-17 compared to improved cases and to unchanged cases (p = 0.004, 0.03 respectively, Dunnett's T3 post hoc multiple test). TNF-α was significantly higher in improved cases compared to deteriorated cases (p =0.03, Dunnett's T3 post hoc multiple test). IL-17 was a significant predictor for macular oedema using linear regression (ß = -0.888, p <0.05). CONCLUSION: Elevation of IL-1α, IL-1ß, IL-4, IL-5, IL-10, IL-13, and IL-17 in the serum of AMD patients supports the hypothesis of AMD as an inflammatory disease. Patients with high IL-17 and TNF-α serum levels were more likely to have a favourable course under VEGF therapy. These cytokines may be used as easy-to-obtain biomarkers.

Low concentrations of ethanol but not of dimethyl sulfoxide (DMSO) impair reciprocal retinal signal transduction.

BACKGROUND: The model of the isolated and superfused retina provides the opportunity to test drugs and toxins. Some chemicals have to be applied using low concentrations of organic solvents as carriers. Recently, E-/R-type (Cav2.3) and T-type (Cav3.2) voltage-gated Ca(2+) channels were identified as participating in reciprocal inhibitory retinal signaling. Their participation is apparent, when low concentrations of NiCl2 (15 µM) are applied during superfusion leading to an increase of the ERG b-wave amplitude, which is explained by a reduction of amacrine GABA-release onto bipolar neurons. During these investigations, differences were observed for the solvent carrier used. METHODS: Recording of the transretinal receptor potentials from the isolated bovine retina. RESULTS: The pretreatment of bovine retina with 0.01 % (v/v) dimethylsulfoxide did not impair the NiCl2-mediated increase of the b-wave amplitude, which was 1.31-fold ± 0.03 of initial value (n = 4). However, pretreatment of the retina with the same concentration of ethanol impaired reciprocal signaling (0.96-fold ± 0.05, n = 4). Further, the implicit time of the b-wave was increased, suggesting that ethanol itself but not DMSO may antagonize GABA-receptors. CONCLUSION: Ethanol itself but not DMSO may block GABA receptors and cause an amplitude increase by itself, so that reciprocal signaling is impaired.

The effect of disease-modifying antirheumatic drugs on retinal function in the electrophysiological ex vivo model of the isolated perfused vertebrate retina.

BACKGROUND: Disease-modifying antirheumatic drugs (DMARDs) have been suggested in the treatment of inflammatory ophthalmological diseases. The aim of the present study was to investigate the effects of these DMARDs on bovine retinal function. METHODS: Bovine retina preparations were perfused with a standard solution. After recording stable electroretinograms the nutrient solution was substituted by a DMARD medium with varying concentrations of different drugs (etanercept and infliximab) for 30 min. Afterwards b-wave recovery was observed. RESULTS: Significant decreases in the b-wave amplitude (p < 0.05) were found for etanercept 0.5 mg/ml (p = 0.0022). Infliximab 2 mg/ml (p = 0.1276) did not result in any statistically significant b-wave reduction. CONCLUSION: The presented data suggest that infliximab might have the better safety profile than etanercept.

A TGF-ß receptor 1 inhibitor for prevention of proliferative vitreoretinopathy.

This study evaluates the use of the TGF-ß receptor 1 inhibitor LY-364947 (LY) to prevent proliferative vitreoretinopathy (PVR). For the in vitro experiments Human Tenon's Fibroblasts (HTFs) and retinal pigment epithelial (RPE) cells were treated with different concentrations of LY to determine HTF proliferation and RPE transdifferentiation. For in vivo testing 30 rabbits underwent a PVR trauma model. The animals received different concentrations of intravitreally injected LY, with or without vitrectomy. LY treatment reduced HTF proliferation and RPE transdifferentiation in vitro. In vivo intravitreal injection of LY prevented PVR development significantly. This positive effect was also present when LY injection was combined with vitrectomy. Intravitreal injection of LY prevented tractional retinal detachment in 14 out of 15 animals. In conclusion, treatment with the TGF-ß receptor 1 inhibitor LY reduces HTF proliferation and RPE transdifferentiation in vitro and prevents proliferative vitreoretinopathy and subsequent tractional retinal detachment in vivo.

Testing the effects of the dye acid violet-17 on retinal function for an intraocular application in vitreo-retinal surgery.

PURPOSE: To facilitate epiretinal or inner limiting membrane peeling, dyes like Indocyanine Green (ICG) as well as Trypan Blue (TB) were used so far. However, toxic effects on the retina were described for both dyes. The aim of our study was to investigate the effects of a novel vital dye Acid violet-17 (AV-17) on retinal histology and function to assess a possible application in vitreo-retinal surgery. METHODS: AV-17 was dissolved in a solvent with heavy water. An electroretinogram was recorded on perfused bovine retina. After reaching stable b-wave amplitudes, AV-17 (0.125-0.5 mg/ml) or the solvent was applied epiretinally for 30-300 seconds. The b-wave amplitudes were recorded before, during, and after treatment. Cultures of bovine retina were incubated for 30 or 300 seconds with the dye or solvent and processed for live/dead staining, immunohistochemistry, and immunoblotting. RESULTS: Reductions of the b-wave amplitudes were observed directly after the exposure to AV-17, which were rapidly and completely reversible within the recovery period for all exposure times at the concentrations of 0.125 and 0.25 mg/ml as opposed to the partial recovery after exposure to 0.5 mg/ml. A high degree of damage in the ganglion cell layer (GCL) and glial reactivity were detected at the concentrations of 0.25 and 0.5 mg/ml but not after exposure to lower concentrations or the solvent. CONCLUSION: Application of AV-17 at a concentration of up to 0.125 mg/ml was well tolerated in terms of retinal function, survival in the GCL, and glial reactivity whereas higher concentrations are not recommended.

The concentration-dependent effects of indocyanine green on retinal function in the electrophysiological ex vivo model of isolated perfused vertebrate retina.

BACKGROUND: Dye solutions such as indocyanine green (ICG) are used for the staining of intraocular structures. The aim of the presented study was to investigate the effects of ICG on bovine retinal function using different concentrations of ICG. METHODS: Bovine retina preparations were perfused with a standard solution and the electroretinogram was recorded. The nutrient solution was substituted by an ICG solution at varying concentrations for 45 min. Afterwards the preparations were reperfused with standard solution for at least 85 min. RESULTS: Significant reductions in b-wave amplitude were found for concentrations of 0.0025% (p = 0.0099) and 0.025% (p = 0.0378). For the concentration of 0.025%, the b-wave amplitude remained significantly decreased (p = 0.0082) after the observation period, but a full recovery of the b-wave was observed for the concentration of 0.0025% (p = 0.1917). CONCLUSION: Intraocular application of sufficient ICG concentrations for internal limiting membrane staining seems not possible without interfering with retinal function.

The neuroprotective potential of Rho-kinase inhibition in promoting cell survival and reducing reactive gliosis in response to hypoxia in isolated bovine retina.

AIMS: To investigate the outcomes of Rho-kinase inhibition in the electrophysiological ex vivo model of the isolated perfused vertebrate retina under hypoxia. METHODS: Bovine retinas were perfused with an oxygen saturated nutrient solution with or without the Rho-kinase inhibitor H-1152P. The retinas were stimulated repeatedly until stable amplitudes were reached and the electroretinogram was recorded at five minute intervals. Hypoxia was induced for 15, 30, and 45 minutes, after which the oxygen saturation was restored. The extent of the cell damage and glial reactivity was determined by Ethidium homodimer-1 staining, immunohistochemistry, and Western blot. RESULTS: Hypoxia caused a time-dependent reduction of the b-wave amplitudes, which could not be prevented by the H-1152P. Although the Rho-kinase inhibitor maintained higher b-wave amplitudes, these effects did not reach statistical significance. Hypoxia also resulted in an increase in cell damage and the activation of the glial cells in the untreated retinas whereas the administration of H-1152P significantly reduced the extent of these events. CONCLUSION: H-1152P exerted a neuroprotective effect against necrosis on the isolated bovine retina under hypoxia together with a reduction in glial cell reactivity. However, the inhibitor could not prevent the hypoxia induced retinal dysfunction possibly due to the interference with synaptic modulation.

Ranibizumab as adjuvant in the treatment of rubeosis iridis and neovascular glaucoma--results from a prospective interventional case series.

BACKGROUND: To evaluate the capability of adjuvant intraocular ranibizumab (Lucentis) injections in the treatment of rubeosis and intraocular pressure in patients with rubeosis and neovascular glaucoma. METHODS: Ten eyes with rubeosis (R) and ten eyes with neovascular glaucoma (NVG) received Lucentis injections (ranibizumab 0.5 mg/0.05 ml) in this prospective, monocenter, 12-months, interventional case series. The primary efficacy outcome measure was the change of degree of iris rubeosis as documented by iris fluorescein angiography measured after 12 months. Secondary outcomes were intraocular pressure (IOP), best-corrected visual acuity (BCVA, logMAR), numbers of additional interventions or antiglaucoma medications administered after injection, the gonioscopic status of the anterior chamber angle, and central retinal thickness. RESULTS: In the R group, 3.6 injections and in the NVG group 2.3 injections of Lucentis were administered. Additional treatments were photocoagulation (n = 19), cyclodestructive procedures (n = 9), cryopexy (n = 3), and vitrectomy (n = 1). The mean stage of rubeosis was 3.4 ± 0.7 in the R group and 3.6 ± 0.8 in the NVG group at baseline. At month 12, the rubeosis was almost resolved in the R group (0.1 ± 0.3, p < 0.001), and decreased significantly in the NVG group (0.7 ± 1.1, p < 0.001). In the NVG subgroup, mean IOP was 41.4 ± 13.4 mmHg at baseline, which decreased rapidly (18.2 ± 12.3, day-14, p = 0.005) and stabilized during the follow-up (15.6 ± 2.0 mmHg, p < 0.05). BCVA improved significantly in both groups (p < 0.05, at month 12). CONCLUSIONS: Injection of 0.5 mg ranibizumab appears to be beneficial as an adjuvant treatment in neovascular glaucoma and rubeosis due to its anti-angiogenic properties and its ability to prevent establishment or progression of anterior chamber angle obstruction. Conventional therapeutic procedures addressing the retinal ischemia are still required in a stage-wise treatment approach.

Effect of high-intensity irradiation from dental photopolymerization on the isolated and superfused vertebrate retina.

BACKGROUND: Light or electromagnetic radiation may damage the neurosensory retina during irradiation of photopolymerizing resinous materials. Direct and indirect effects of irradiation emitted from polymerisation curing light may represent a severe risk factor for the eyes and the skin of the lamp operators, as well as for the patient's oral mucosa. METHODS: Bovine superfused retinas were used to record their light-evoked electroretinogram (ERG) as ex vivo ERGs. Both the a- and the b-waves were used as indicators for retinal damage on the functional level. The isolated retinas were routinely superfused with a standard nutrient solution under normoglycemic conditions (5 mM D-glucose). The change in the a- and b-wave amplitude and implicit time, caused by low and high intensity irradiation, was calculated and followed over time. RESULTS: From the results, it can be deduced that the irradiation from LED high-power lamps affects severely the normal physiological function of the bovine retina. Irradiations of 1,200 lx irreversibly damaged the physiological response. In part, this may be reversible at lower intensities, but curing without using the appropriate filter will bleach the retinal rhodopsin to a large extent within 20 to 40 s of standard application times. CONCLUSION: Constant exposure to intense ambient irradiation affects phototransduction (a-wave) as well as transretinal signalling. The proper use of the UV- and blue-light filtering device is highly recommended, and may prevent acute and long lasting damage of the neurosensory retina.

The retinal biocompatibility of dyes in the ex vivo model of the isolated superfused vertebrate retina.

BACKGROUND: Peeling of the internal limiting membrane or epiretinal membranes is a successful principle in macular surgery to achieve a functional benefit. Different dyes are used to facilitate the identification of intraocular tissues. The aim of our work was to investigate the retinal tolerance to the different dyes and their solvent carriers to provide valuable data for surgeons in handling for an optimal intraoperative use. METHODS: Using the ex vivo model of the isolated superfused vertebrate retina technique, the effects of the dyes were tested on human and bovine retinal function. The retinas were perfused with an oxygen preequilibrated standard solution. The electroretinogram (ERG) was recorded using Ag/AgCl electrodes. After recording stable ERG amplitudes, the dyes brilliant blue G, indocyanine green, trypan blue, patent blue, triamcinolone and their solvent carriers were investigated. RESULTS: Reductions of the ERG amplitudes were found for each tested dye. The effects after application of the dyes were dependent on time and concentration of the applied dyes, which were different for each dye. CONCLUSION: In part, the ERG has shown strong effects already after a short period of dye application. Surgeons who rely on the intraocular use of the dyes should keep in mind our findings, and the use of some dyes should be limited to selected cases. The well-considered use of the dyes by the surgeons could lead to a better functional outcome and avoid a possible harmful outcome of the surgery after mishandling.

Morphological and functional outcome after brilliant blue G-assisted macular hole surgery.

PURPOSE OF THE STUDY: To investigate the outcome of brilliant blue G (BBG)-assisted internal limiting membrane peeling in macular hole surgery after a follow-up of 6 months. PROCEDURES: In this retrospective study 20 eyes have been treated with BBG-assisted macular hole surgery. After a follow-up of 6 months, the functional and anatomical outcomes have been analyzed. RESULTS: The mean preoperative best-corrected visual acuity (BCVA) was 0.7 logMAR units (mean ± SD 0.66 ± 0.27). After 3 months, the mean BCVA increased not significantly to 0.4 (0.54 ± 0.30), but a significant improvement to 0.2 logMAR units (0.28 ± 0.23) could be detected after 6 months compared to baseline (p < 0.01). Primary macular hole closure after a single surgery was found in 17 of 20 eyes. CONCLUSION AND MESSAGE: BBG exhibits sufficient staining qualities and safety profile leading to a significant functional improvement after successful macular hole surgery.

[Digital teaching 2020: Online teaching receives a better assessment than face-to-face teaching]. / Digitale Lehre 2020: Online-Unterricht erhält bessere Bewertung als Präsenzunterricht.

BACKGROUND: Due to the corona pandemic, face-to-face teaching was no longer permitted in the summer semester 2020 and online alternatives were quickly found. OBJECTIVE: In our article, we illustrate the switch from face-to-face to online teaching in ophthalmology at the University of Lübeck and compare online teaching with face-to-face teaching. METHODS: The central teaching evaluation takes place every semester with a standardized questionnaire. Based on the evaluation of these questions, a direct comparison of the attendance semester of the winter semester 2019/2020 with the online semester of the summer semester 2020 was carried out. RESULTS: The structure (p = 0.003), the organization (p = 0.001), the resources made available (p = 0.034), the attendance of the lectures (p < 0.001) and further dates (p = 0.041), the increase in interest (p = 0.039) and learning (p = 0.001) were rated better in the online semester than in the face-to-face semester. Overall, the digital summer semester 2020 (p < 0.01) received a significantly better overall grade than the face-to-face semester in winter 2019/2020. CONCLUSION: The structure of our courses has also been proven online. The theoretical content could be excellently mediated; however, practical exercises are not possible online. For the learning of practical skills, face-to-face instruction is still necessary.

Ca(v)2.3 Ca2+ channel interacts with the G1-subunit of V-ATPase.

BACKGROUND: Calcium channels are essential in coupling action potential to signal transduction in cells. There are several types of calcium channels, which can be pharmacologically classified as L-, N-, P/Q-, R- and T-type. But molecular basis of R-type channels is less clearly understood compared the other channel types. Therefore the current study aims at understanding the molecular functions of R-type calcium channels by identifying interaction partners of the channel. METHODS: In order to do so, a yeast two hybrid (Y2H) screen, with carboxy terminus of α1 subunit of the channel, as the bait, was performed. G1 subunit of v-ATPase was identified as a putative interaction partner of human Ca(v)2.3 by using the Y2H screening. The interaction was confirmed by immunoprecipitation. To study the functional importance of the interaction, bafilomycin A(1), a potent and specific inhibitor of v-ATPase was used in patch-clamp recordings in Ca(v)2.3 stably-transfected HEK-293 cells (2C6) as well as in electroretinography of the isolated bovine retina expressing R-type Ca(2+) channels. RESULTS: G1 subunit of v-ATPase interacts with C-terminal tail of Ca(v)2.3 and bafilomycin A(1) reduces Ca(v)2.3 mediated calcium currents. Additionally peak I(Ca) is inhibited in retinal signal transduction when recorded as ERG b-wave. CONCLUSIONS: The results suggest that v-ATPase interacts physically and also functionally with Ca(v)2.3. This is the first demonstration of association of Ca(v)2.3 C-terminus with a protein complex which is involved in transmembrane signalling.

The novel use of decorin in prevention of the development of proliferative vitreoretinopathy (PVR).

BACKGROUND: The cytokine transforming growth factor-ß (TGF-ß) is a pivotal contributor to tissue fibrosis and a key cytokine in the pathogenesis of cellular transdifferentiation, epithelial-mesenchymal transition (EMT), and cell adhesion. This study evaluates the effect of decorin, a naturally occurring TGF-ß inhibitor, in an experimental rabbit model for proliferative vitreoretinopathy (PVR). METHODS: Traumatic PVR was induced in 50 rabbits divided into ten groups (n = 5). One group (GI) reveals a control with no treatment after trauma. Groups (GII-GIV) consisted of subgroups receiving phacovitrectomy at three different time points; (a) at the time of trauma, (b) 1 week following trauma, and (c) 2 weeks following trauma. GIII and GIV received 100 µg or 200 µg decorin, respectively. PVR severity was scored from 0 to 4. The amount of fibrosis was quantified using JMicroVision© software. RESULTS: The control group GI developed severe PVR with tractional retinal detachment (TRD); (PVR score ≥2) in four rabbits out of five. Vitrectomy had a positive effect (p < 0.05) on PVR development when preformed immediately, however the developed fibrosis was high. The best results were obtained when surgery was used in conjunction with decorin that reduced both the PVR score and fibrosis development significantly (p < 0.05). Depending on dosage and time of vitrectomy, PVR could be completely avoided (PVR score = 0) in 16 rabbits out of 30. TRD was prevented in 13 rabbits out of 15 in GIII to 14 rabbits out of 15 in GIV. In decorin-treated eyes, vitrectomy outcome was best when preformed at 1 week after trauma. There were no drug-related toxic effects evident on clinical and histopathological examination. CONCLUSIONS: In conclusion, in this rabbit model of PVR, adjuvant decorin application during vitrectomy effectively reduces fibrosis and TRD development. In conjunction with no obvious histopathological toxicity signs, decorin represents a promising substance to inhibit PVR reactions.

[Digital teaching 2020: students assess attention during an online lecture as equivalent to a face-to-face lecture]. / Digitale Lehre 2020: Studenten schätzen die Aufmerksamkeit während einer Onlinevorlesung gleichwertig zu einer Präsenzvorlesung ein.

BACKGROUND: The corona pandemic has led to short-term adjustments of the procedures in medical courses. In many departments classroom teaching was no longer possible so that it was necessary to implement digital courses to provide an adequate medical training. METHODS: We developed a digital curriculum based on the contents of our established courses using primary in-house tools, such as Cisco WebEx and Moodle. We then performed a student survey to evaluate the implementation of the concept. RESULTS: The evaluation showed good ratings according to teaching content and didactics. The communication with the students and between each other was also considered good. Students assessed attention during the course to be equivalent in comparison to classroom teaching. As expected, the training of practical skills was evaluated as poor. For future courses most of the students could imagine a combination of digital and classroom teaching. DISCUSSION: Implementing a digital course was a sudden challenge for students and tutors. With suitable software solutions and good communication, it is possible to adequately teach theoretical content via digital courses. Students assessed the digital training in most parts to be a good and an equivalent option compared to classroom teaching. A remaining problem is the lack of practical training.

The safety profile of alkylphosphocholines in the model of the isolated perfused vertebrate retina.

BACKGROUND: Alkylphosphocholines (APCs) are synthetic phospholipid derivatives, and have been demonstrated to inhibit ocular cell proliferation in vitro and in vivo. Currently, they are applied clinically for their antitumoral and antiparasitic properties, but have not yet been implemented for clinical use in proliferative ophthalmic disorders. The purpose of this study was to assess the safety of APC in the ex vivo model of the isolated perfused vertebrate retina. METHODS: Bovine retina preparations were perfused with an oxygen pre-equilibrated standard solution. The electroretinogram (ERG) was recorded using Ag/AgCl-electrodes. After recording stable b-wave amplitudes, an APC was applied at the following concentrations to the nutrient solution: 0.25 microM, 2.5 microM and 25 microM. To investigate the effects of APC on photoreceptor function, a test series at the same concentrations was performed to evaluate the effects of APC on the a-wave amplitude. Aspartate at a concentration of 1 mM was added to the nutrient solution to obtain stable a-wave amplitudes. Thereafter, APC was applied at the same concentrations to the nutrient solution. The recovery of the ERG amplitudes was followed up for 75 minutes. RESULTS: No reduction of the a- and b-wave amplitude was found at the end of the exposure time with APC added in each test series. No differences were found between the ERG amplitudes before and after application of APC at the end of the washout. CONCLUSIONS: In the ex vivo model of the isolated perfused vertebrate retina, APC has proved to be a safe compound in the concentrations applied. Thus, APCs should further be considered as promising candidates for future clinical applications in ophthalmology.

Intravitreal bevacizumab treatment of macular edema in central retinal vein occlusion: one-year results.

PURPOSE: To report on the anatomic and visual acuity response after intravitreal bevacizumab injection in patients with macular edema due to non-ischemic central retinal vein occlusion (CRVO). METHODS: In a retrospective study, 21 consecutive patients (21 eyes) with non-ischemic CRVO underwent, on average, 3.7 intravitreal bevacizumab injections (1.25 mg). Ophthalmic examination included best corrected visual acuity (BCVA) and central retinal thickness (CRT) at baseline and follow-up visits. Fluorescein angiography was performed at baseline and at follow-up visits if needed. Primary outcomes were change of BCVA and CRT. RESULTS: The follow-up period for all of the included patients was 12 months. The mean BCVA was unchanged at the 12-month examination (baseline: 20/160; 12 months: 20/160) (P = 0.771). The mean CRT decreased from 780 microm (standard deviation [SD] +/- 324 microm) at the baseline to a mean of 462 microm (SD +/- 248 microm) at 12 months (P < 0.05). CONCLUSION: Intravitreal bevacizumab resulted in a significant decrease in CRT without significant improvement of visual acuity in patients with non-ischemic CRVO after a follow-up of 12 months.