Retinal pigment epithelial (RPE) cells provide crucial functions for the maintenance of the retinal environment. We investigated the phagocytotic mechanisms of RPE cells evaluating the question whether particle uptake underlies a diurnal rhythm. Additionally, a possible connection of volume regulation and the phagocytotic function of RPE cells was studied. As antiviral nucleoside analogues influence cell-volume-regulating mechanisms, we tested several antiviral drugs. Cultured primary RPE cells and a permanent cell line (ARPE-19) were tested for uptake of europium-labeled microspheres quantified by time-resolved fluorometry. Cells were also exposed to cyclic illumination or continuous light and dark culture conditions. Inhibitors of cytoskeleton (microtubuli, actin) and osmotic swelling were also tested. Ingested FITC-labeled microparticles were found in phagosomes strongly associated which the cytoskeleton as they could not be easily moved by laser tweezer microscopy. Phagocytosis was observed predominately during dark intervals and was reduced by continuous light exposure. The diurnal rhythm of unsynchronized RPE cultures was abolished by microtubule inhibitors although no inhibition of overall particle uptake by cytoskeletal blockers was observed. Hypoosmotic swelling of RPE also decreased phagocytosis. Acyclovir was found inhibitory in ARPE-19 cells, whereas azidothymidine showed a protracted inhibiting activity on primary RPE cells and ganciclovir was inactive in both cell types. The presence of a diurnal rhythm also in culture indicates genetic determination of light-regulated particle uptake. This mechanism appears to be influenced by the regulation of cell volume and microtubule function. Inhibition of RPE function by antiviral drugs is a novel finding and in accordance with interferences of the tested drugs with cellular chloride channels described earlier. It may give a hint towards possible ocular side effects in the long-term use of nucleoside-analogous substances.
Purpose
The clinical diagnosis of ocular surface squamous neoplasia is challenging, mostly requiring excisional biopsy. Human tumor angiogenesis is characterized by abnormal vessel architecture and transvascular hyperpermeability. This case report describes features of fluorescein and indocyanine green angiography in a case of conjunctival intraepithelial neoplasia.
Observations
Color photography, optical coherence tomography, fluorescein and indocyanine green angiography were performed in a patient with suspected conjunctival intraepithelial neoplasia before excisional biopsy and histologic confirmation of clinical diagnosis. Fluorescein dye showed extensive early extravascular dye leakage within the limits of the lesion. Indocyanine green dye displayed corneal terminal vessel bulbs with early leakage after 70 seconds and showed diffuse intralesional dye leakage after 7 minutes.
Conclusions
Increased fluorescein and early indocyanine green dye leakage can be used to confirm active angiogenesis already in early stages of dysplastic ocular surface squamous neoplasia. Late leakage of indocyanine green dye may be due to chronic transvascular hyperpermeability within intrinsic tumor vessels. The leakage behaviour of intravenous dyes has the potential to serve as a diagnostic indicator of active growth in dysplastic ocular surface neoplastic lesions.
Purpose: To report the efficacy of reduced-fluence photodynamic therapy (PDT) combined with intravitreal ranibizumab for the treatment of nonproliferative macular telangiectasia (MacTel) type 2. Methods: Noncomparative, interventional, retrospective case series; 5 eyes of 4 patients were studied. Patients were treated with reduced-fluence PDT and intravitreal ranibizumab within 24 h. After initial treatment, follow-up was at least 12 months in all patients. Results: At baseline median logMAR (logarithm of the minimal angle of resolution) best-corrected visual acuity (BCVA) was 1.0 (range, 1.0-0.3). At 3 months of follow-up vision increased in 3 out of 5 eyes and median BCVA was 0.4 (range, 1.0-0.2). The gain of BCVA ranged from 6 lines to 1 line. Visual acuity remained stable in the other 2 study eyes. No eyes lost vision at 3 months of follow-up. At 12 months of follow-up median logMAR BCVA was 0.7 (range, 1.3-0.3). Two eyes had maintained their gain in BCVA compared to baseline. Two eyes lost vision compared to baseline and 1 eye showed unchanged visual acuity at 12 months of follow-up. Conclusion: A combination therapy with reduced-fluence PDT and intravitreal ranibizumab might be a valuable treatment option for eyes with progressive vision loss due to nonproliferative MacTel type 2.
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