Gunay, Murat; Tugcugil, Ersagun; Somuncu, Ahmet Mehmet; Kola, Mehmet; Turk, Adem; Uzlu, Dilek; Kose, Busra; Erdol, Hidayet

Purpose: To investigate the potential benefits and practicality of ultra – wide field (UWF) imaging and intravenous UWF fluorescein angiography (IV UWF – FA) in infants with retinopathy of prematurity (ROP) using an Optos® California device. Methods: This retrospective study involved 46 infants with a history of ROP who underwent UWF imaging with or without IV UWF – FA. ROP characteristics were identified using UWF color imaging. Retinal vascular findings following treatment were also assessed at IV UWF – FA analysis. All imaging sessions were performed under topical anesthesia without sedation. Main outcomes were the appearance of ROP at UWF color imaging and IV UWF–FA analysis, including status of ROP, neovascularizations, presence of plus disease, retinal vascular details, and resolution after treatment. Results: Seven (three girls) of the 46 infants (22 girls) underwent IV UWF–FA. Twelve IV UWF–FA sessions were performed in total. The oldest infant during IV UWF–FA analysis was at 55 postmenstrual weeks. Clinical characteristics of disease were easily identified at UWF color imaging. IV UWF–FA images also clearly revealed non-perfused retinal areas, fluorescein leakage, macular edema, retinal vascular abnormalities, and the status of the peripheral vascular termini. Complications of IV UWF–FA occurred in one infant in the form of patchy yellow skin discoloration around the injection site which completely disappeared on the first day following the procedure. Conclusions: Providing a high resolution panoramic view of the retina in a single image capture with no need for contact with the cornea appear to represent potential advantages of UWF imaging in infants with ROP. IV UWF–FA also seems to be a safe procedure which can be performed under topical anesthesia and that shows detailed retinal vascular alterations in patients with ROP.

Ruhi, Mustafa Kemal; Ak, Ayşe; Gülsoy, Murat

The Food and Drug Administration-approved Indocyanine Green can be used as a photosensitizer to kill cancer cells selectively. Although indocyanine green is advantageous as a photosensitizer in terms of strong absorption in the near-infrared region, indocyanine green-based cancer treatment is still not approved as a clinical method. Some reasons for this are aggregation at high concentrations, rapid clearance of the photosensitizer from the body, low singlet oxygen quantum yield, and the uncertainty concerning its action mechanism. This in vitro study focuses on two of these points: “what is the cell inhibition mechanism of indocyanine green-based therapy?” and “how the dose-dependent aggregation problem of indocyanine green alters its cell inhibition efficiency?” The following experiments were conducted to provide insight into these points. Nontoxic doses of indocyanine green and near-infrared laser were determined. The aggregation behavior of indocyanine green was verified through experiments. The singlet oxygen quantum yield of indocyanine green at different concentrations were calculated. Various indocyanine green and energy densities of near-infrared light were applied to prostate cancer, neuroblastoma, and colon cancer cells. An MTT assay was performed at the end of the first, second, and third days following the treatments to determine the cell viability. Temperature changes in the medium during laser exposure were recorded. ROS generation following the treatment was verified by using a Total Reactive Oxygen Species detection kit. An apoptosis detection test was performed to establish the cell death mechanism and, finally, the cellular uptakes of the three different cells were measured. According to the results, indocyanine green-based therapy causes cell viability decrease for three cancer cell lines by means of excessive reactive oxygen species production. Different cells have different sensitivities to the therapy possibly because of the differentiation level and structural differences. The singlet oxygen generation of indocyanine green decreases at high concentrations because of aggregation. Nevertheless, better cancer cell killing effect was observed at higher photosensitizer concentrations. This result reveals that the cellular uptake of indocyanine green was determinant for better cancer cell inhibition.