Serdal Çelebi

Effects of melatonin, vitamin E and octreotide on lipid peroxidation during ischemia-reperfusion in the guinea pig retina

Purpose The purpose of this study is to provide evidence that free radical damage is a component of retinal ischemia-reperfusion (I/R) injury, and to determine whether melatonin, vitamin E and octreotide can protect the retina from this injury. Methods The right eyes of 50 male guinea pigs weighing 500–600 g were used. The animals were randomly assigned to group 1 (control), group 2 (I/R), group 3 (melatonin + I/R), group 4 (vitamin E + I/R) and group 5 (octreotide + I/R). Groups 3, 4 and 5 received four subcutaneous injections with a 6-h interval for a total daily dose of 10 mg/kg melatonin, 150 mg/kg vitamin E and 22 μg/kg octreotide. The first dose of each substance was administered 5 minutes before retinal ischemia, which was induced for 1.5 hours, followed by reperfusion for 24 hours. All three substances were repeated for 6, 12 and 18 hours during reperfusion. The animals were killed at 24 hours of reperfusion. Retinas were isolated and processed for the quantification of malondialdehyde (MDA). Results The compounds had the following relationships: melatonin more than vitamin E more than octreotide in preventing retinal damage by ischemia-reperfusion. All three gave significant protection against the formation of MDA (10.4±2.3, 12.4±2.4, 13.9±1.5 nmol/100 mg tissue wet weight, respectively) compared to the control (3.7±1.3 nmol/100 mg tissue wet weight) and I/R groups (22.7±6.2 nmol/100 mg tissue wet weight). Conclusions This study demonstrates the inhibitory effect of melatonin, vitamin E and octreotide on MDA levels during retinal ischemia-reperfusion injury.

Effect of Smoking on Choroidal Thickness in Healthy Smokers

Abstract Purpose: To evaluate the acute and chronic effects of cigarette smoking on the choroidal thickness of young male smokers with smoking histories exceeding 10 years using spectral domain optical coherence tomography (SD OCT). Materials and methods: The right eyes of 40 never-smoking and 30 smoking healthy subjects were included in this study. We measured the choroidal thicknesses of the never-smoking subjects as a control group. The choroidal thicknesses of the smoking subjects were measured before, 5, 30 and 60 min after smoking. Choroidal thickness measurements were taken at the fovea and at two points that were 1500 µm nasal and temporal to the fovea. Results: No significant difference was found for the retinal thickness, choroidal thicknesses, spherical equivalent, intraocular pressure and central corneal thickness of the smokers and non-smokers (p > 0.05 for all). In the measurements that were taken after smoking, a statistically significant increase was found in choroidal thickness that was observed between 0 and 5 min for the central, nasal and temporal segments (p < 0.001 for all). Conclusions: Smoking caused acute, significant increase in choroidal thickness that returned to baseline levels after 1 h. The choroidal and retinal thicknesses did not differ significantly between the healthy young smokers and non-smokers.

Aqueous humour and serum concentration of asymmetric dimethyl arginine in pseudoexfoliation syndrome

Objective Asymmetric dimethyl arginine (ADMA) is the major endogenous inhibitor of nitric oxide synthase. ADMA is related to endothelial dysfunction and is an independent cardiovascular risk factor. This study aimed to evaluate the concentration of ADMA in aqueous humour and serum samples of patients with pseudoexfoliation (PEX) syndrome. Materials and Methods 21 cataract patients with PEX syndrome (PEX group) and 18 cataract patients without PEX syndrome (control group) were enrolled in the study. ADMA was measured in the aqueous humour and serum of the PEX and control groups. ELISA was used to determine the ADMA concentration. Results Mean aqueous humour ADMA concentration in the PEX group was 0.39±0.07 μmol/l and in the control group was 0.34±0.06 μmol/l. Mean serum ADMA concentration in the PEX group was 0.56±0.21 μmol/l and in the control group was 0.44±0.12 μmol/l. ADMA concentration of aqueous humour in the PEX group was significantly higher than the control group (p=0.026). Similarly, ADMA concentration of serum in the PEX group was significantly higher than the control group (p=0.039). Conclusions The findings of the present study could suggest that ADMA might play a role in the aetiopathogenesis of PEX syndrome. Higher aqueous and serum levels of ADMA might be potential evidence of endothelial dysfunction in PEX syndrome.

Isolated lateral rectus muscle involvement as a presenting sign of euthyroid Graves disease

A 27-year-old man who presented with diplopia and proptosis and was diagnosed with euthyroid Graves disease and restrictive strabismus. It was determined that his symptoms were caused by isolated lateral rectus muscle involvement. Diplopia resolved and ocular motility improved substantially following 6 weeks of oral corticosteroid therapy.

Investigation of the choroidal thickness in patients with hypothyroidism.

Purpose: The effect of hypothyroidism on the choroidal thickness (CT) was investigated in patients with subclinical hypothyroidism and overt hypothyroidism, and biochemically and clinically euthyroid patients receiving levothyroxine treatment. The patients were compared with healthy subjects. Materials and Methods: One eye of 71 hypothyroid and 22 healthy subjects between 20 and 40 years of age were included in this study. CT measurements were taken at the fovea and at 2 points that were 1500 μm nasal and temporal to the fovea using spectral-domain optical coherence tomography. Independent sample t-tests and was used for statistical analysis of the data. Results: The CT was significantly thicker in hypothyroid patients compared to healthy subjects (P values were 0.013 for subfoveal, 0.015 for temporal and 0.020 for nasal segments). The intraocular pressure (IOP) and body mass index (BMI) were also significantly higher in hypothyroid patients (P values were 0.021 and 0.003, respectively). There was not a statistically significant difference in the BMI and IOP measurements between healthy subjects and euthyroid patients (P > 0.05). However, there was a statistically significant difference in the subfoveal, temporal and nasal CT measurements between healthy subjects and euthyroid patients (P values were 0.006, 0.031 and 0.013, respectively). Conclusions: All subgroups of hypothyroid patients had thicker CT compared to healthy subjects. Euthyroid patients receiving levothyroxine treatment had lower IOP, BMI levels, and serum lipid levels than patients with subclinical hypothyroidism and overt hypothyroidism.

Evaluation of subjects with a moderate cup to disc ratio using optical coherence tomography and Heidelberg retina tomograph 3: Impact of the disc area

Aim: The aim was to evaluate subjects with a moderate cup to disc ratio using optical coherence tomograph (OCT) and Heidelberg retina tomograph (HRT) 3. Settings and Design: We included 80 patients with early glaucoma and 80 nonglaucomatous subjects with moderate cup/disc ratio (range of 0.5–0.8) to this cross-sectional study. Subjects and Methods: We compared results of color-coded algorithms of HRT 3 (Moorfields regression analysis [MRA] and Glaucoma probability score [GPS]) and OCT. All outputs are classified into three categories: Within normal limits (WNLs), borderline and outside normal limits (ONLs). Diagnostic accuracies of algorithms were determined using the highest sensitivity criteria. Results: The sensitivities of global MRA, GPS and OCT were 0.75, 0.925 and 0.725, respectively, in average disc area group and 0.85, 1.0 and 0.425, respectively, in large disc area group. The specificities of global MRA, GPS and OCT were 0.55, 0.15 and 0.85, respectively, in average disc area group and 0.425, 0.025 and 0.80, respectively, in large disc area group. Area under receiver operating characteristic curve (AUROC) of global MRA, GPS and OCT were 0.667, 0.617 and 0.792, respectively, in average disc area group and 0.746, 0.576 and 0.627, respectively, in large disc area group. AUROC of global MRA and OCT combination in the average and large disc area groups were 0.828 and 0.825, respectively. Conclusions: In contrast to GPS and OCT algorithms, diagnostic performance of MRA algorithm increased in large disc area group. Combining MRA and OCT algorithms produced satisfactory diagnostic performance in subjects with an average and large disc area.