Optical coherence tomography imaging in the management of the Argus II retinal prosthesis system

Purpose: To report a real-life experience with the Argus II retinal prosthesis system in blind patients with end-stage retinitis pigmentosa (RP) or choroideremia (CHM), focusing on the pivotal role of optical coherence tomography (OCT) in both preoperative and postoperative management. Methods: This hospital-based case series included 3 blind patients who were uneventfully implanted with Argus II epiretinal device. These patients (2 with RP and 1 with CHM) were selected during the ArgusTM II Retinal Prosthesis System PostMarket Surveillance Study Protocol. Complete screening procedures had involved 66 eyes of 33 patients afferent to the Center for Retinitis Pigmentosa of the Veneto Region. Results: Preoperative OCT examination resulted in the exclusion of 8 eyes in 4 patients with bilateral posterior staphyloma diagnosing unexpected staphylomatous macular patterns in 2 patients with RP and no sign of pathologic myopia. Postoperative OCT study of Argus II proximity to retinal surface indicated a plausible correlation between electrode-retina distance and perceptual threshold in 2 of our 3 patients. In particular, during the first 6 months of follow-up, the patient with the closest contact between device and macula showed a continuous vision-related improvement in the performance of several real-life tasks. Conclusions: The present findings illustrate the modalities by which each different OCT examination is an essential tool to optimize safety and efficacy profiles during Argus II protocol. Optical coherence tomography will be crucial for future investigative approaches on patient selection criteria and next-generation implant design

Anti-Diabetic Effects of the Ethyl-Acetate Fraction of Trichilia catigua in Streptozo-tocin-Induced Type 1 Diabetic Rats

Background/Aims: Trichilia catigua A. Juss., known as “catuaba” in Brazil, has been popularly used as a tonic for fatigue, impotence and memory deficits. Previously, our group demonstrated that the ethyl-acetate fraction (EAF) of T. catigua has antioxidant and anti-inflammatory effects. The present study evaluated the anti-diabetic activity of EAF in type 1 diabetic rats. Methods: Male Wistar rats were divided into four groups (N: non-diabetic group, D: type 1 diabetic group, NC: non-diabetic + EAF group and DC: type 1 diabetic + EAF group). The latter two groups were treated with 200 mg/kg EAF. Type 1 diabetes was induced by intravenous streptozotocin (STZ) injection (35 mg/kg). Starting two days after STZ injection, EAF was administered daily by gavage for 8 weeks. Results: EAF attenuated body mass loss and reduced food and water intake. EAF improved hyperglycaemia and other biochemical parameters, such as alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Furthermore, the number of pancreatic β-cells and the size of the islets had increased by β-cell proliferation in the DC group. EAF promoted reduction in kidney tissue damage in STZ-induced diabetic rats by reduction of renal fibrosis. Conclusion: The present study showed that EAF improves glucose homeostasis and endocrine pancreas morphology and inhibits the development of diabetic nephropathy in STZ-induced diabetic rats