Hasan Ali Tufan

Protective Effect of Hesperetin and Naringenin against Apoptosis in Ischemia/Reperfusion-Induced Retinal Injury in Rats

Purpose. Hesperetin and naringenin are naturally common flavonoids reported to have antioxidative effects. This study was performed to investigate whether either hesperetin or naringenin has a protective effect against apoptosis on retinal ischemia/reperfusion (I/R) injury. Methods. Retinal I/R was induced by increasing the intraocular pressure to 150 mmHg for 60 minutes. Thirty-three male Wistar albino rats were randomised into 5 groups named control, I/R + sham, I/R + solvent (DMSO), I/R + hesperetin, and I/R + naringenin. Animals were given either hesperetin, naringenin, or the solvent intraperitoneally immediately following reperfusion. Thickness of retinal layers and retinal cell apoptosis were detected by histological analysis, tunel assay, and immunohistochemistry assay. Results. Hesperetin and naringenin attenuated the I/R-induced apoptosis of retinal cells in the inner and outer nuclear cells of the rat retina. Retinal layer thickness of the naringenin treatment group was significantly thicker than that of the hesperetin, sham, and solvent groups (P < 0.05). Conclusions. Hesperetin and naringenin can prevent harmful effects induced by I/R injury in the rat retina by inhibiting apoptosis of retinal cells, which suggests that those flavanones have a therapeutic potential for the protection of ocular ischemic diseases.

Effects of Lubricating Agents with Different Osmolalities on Tear Osmolarity and Other Tear Function Tests in Patients with Dry Eye

Abstract Purpose: To evaluate the effects of different artificial tear eye drops on Ocular Surface Disease Index (OSDI), tear osmolarity, Schirmer’s I test, and tear break-up time (TBUT) in patients with dry eye disease. Materials and methods: This 12-week, single-institution, single-masked, randomized, pilot study was conducted in Turkey between March and July 2012 in patients with dry eye. Patients were randomly assigned to receive Systane® for their right eye and Eyestil® for their left eye or to receive Tears Naturale II® for their right eye and Refresh Tears® for their left eyes. Outcomes were assessed at baseline and weeks 2, 4 and 12 after treatment initiation. Results: Twenty-two patients received Systane (right eye) and Eyestil (left eye) and 21 patients received Tears Naturale (right eye) and Refresh (left eye). At each visit and for each outcome, each treatment group demonstrated a significant improvement from baseline (p < 0.001); however, none of these outcomes were significantly different among treatment groups at any visit. At week 12, the mean OSDI improvement was similar between the Systane/Eyestil group (−26.4 ± 10.6) and the Tears Naturale/Refresh group (−27.6 ± 14.8). The mean tear osmolarity decrease (mOsm/L) at week 12 was −33.8 ± 8.3 for Eyestil, −30.3 ± 9.2 for Refresh, −28.4 ± 8.2 for Systane and −25.7 ± 13.1 for Tears Naturale. The mean Schirmer’s test increase at week 12 (mm/5 min) was 6.7 ± 3.4 for Eyestil, 6.4 ± 2.9 for Systane, 4.7 ± 2.4 for Tears Naturale and 4.7 ± 2.8 for Refresh. The mean TBUT increase at week 12 (s) was 7.0 ± 3.4 for Systane, 6.1 ± 3.3 for Eyestil, 5.8 ± 2.3 for Tears Naturale, and 5.6 ± 2.8 for Refresh. Conclusion: All four artificial tear formulations were effective in relieving dry eye signs and symptoms. Although the greatest improvement in two of the objective tests was achieved by Eyestil, the drug with the lowest osmolality, differences among the four artificial tear eye drops were not statistically significant.

The protective effects of dexmedetomidine against apoptosis in retinal ischemia/reperfusion injury in rats.

Abstract Objective: Dexmedetomidine is an alpha 2 adrenoceptor agonist and can be used for postoperative sedation, analgesia and anesthesia-sparing properties. Furthermore, the neuroprotective effects against ischemia/reperfusion (I/R) injury in the central nervous system have been shown in experimental studies. This study aimed to investigate the protective effects of dexmedetomidine against apoptosis in retinal I/R injury in the rat. Materials and methods: Retinal I/R injury was induced by transient elevation of intraocular pressure. Eighteen animals were divided into three groups (n = 6): sham, I/R and treatment. The I/R injury and protective effects of the dexmedetomidine were evaluated by retinal thickness determined by histological sections, terminal deoxynucleotidyl transferase-mediated biotin-deoxyuridine triphosphate nick-end labeling (TUNEL) and immunohistochemistry of caspases 3. Results: A decrease in the retinal thickness and an increase in the apoptotic cells were found to be statistically significant in I/R and treatment groups when compared with the control group. However, in comparison with the I/R group we realized that the administration of dexmedetomidine reduced the thinning of retinal thickness and also decreased the number of caspases 3 and TUNEL-positive cells. Conclusion: Dexmedetomidine is protective against apoptosis in retinal I/R injury in rats.

Alterations in Iris Structure and Pupil Size Related to Alpha-1 Adrenergic Receptor Antagonists Use: Implications for Floppy Iris Syndrome

PURPOSE To evaluate structural alterations of iris and pupil diameters (PDs) in patients using systemic α-1-adrenergic receptor antagonists (α-1ARAs), which are associated with intraoperative floppy iris syndrome (IFIS). METHODS Eighty-eight eyes of 49 male were evaluated prospectively. Patients were assigned to 2 different groups. Study group included 23 patients taking any systemic α-1ARAs treatment, and control group included 26 patients not taking any systemic α-1ARAs treatment. All patients underwent anterior segment optical coherence tomography to evaluate iris thickness at the dilator muscle region (DMR) and at the sphincter muscle region (SMR). The PD was measured using a computerized infrared pupillometer under scotopic and photopic illumination. RESULTS The study group included 46 eyes of 23 patients and the control group included 42 eyes of 26 patients. Most treated patients were on tamsulosin (16/23). Mean age was similar in the study and control groups (61.9±7.1 vs. 60.3±8, 2 years, nonsignificant). DMR (506.5±89.4 vs. 503.6±83.5 μm), SMR (507.8±78.1 vs. 522.1±96.4 μm) and the DMR/SMR ratio (1.0±0.15 vs. 0.99±0.23 μm) was similar in the study and control groups and these differences were nonsignificant. Scotopic PDs were also similar in both groups (3.99±1.11 vs. 3.74±1.35, nonsignificant). A significantly reduced photopic PD (2.89±0.55 vs. 3.62±0.64, P<0.001) and an increased scotopic/photopic PD (1.42±0.44 vs. 1.02±0.30, P<0.001) were found in the study group. CONCLUSIONS Evaluating PD alterations might be more useful than evaluating iris structural alterations in predicting IFIS. There is still a need for a reliable method that will determine the possibility of IFIS.

Effect of Topically Applied Azithromycin on Corneal Epithelial and Endothelial Apoptosis in a Rat Model of Corneal Alkali Burn.

Purpose: To investigate the antiapoptotic effect of topically administered azithromycin (AZM) on corneal epithelial and endothelial cells in a rat model of corneal alkali burn. Methods: Twenty-four Wistar albino rats were divided into 4 equal groups as pseudovehicle (group 1), control (group 2), alkali burned (group 3), and treatment (group 4) groups. Alkali injury was induced only in the right corneas of rats belonging to groups 3 and 4 using 1N NaOH. The rats in group 3 and the rats in group 4 were respectively treated either with an artificial tear gel or with 1.5% AZM eye drops for 5 days. At the fifth day of the experiment, the apoptosis in the corneal epithelium and endothelium of all rats was assessed using a terminal dUTP nick-end labeling (TUNEL) assay. In addition, tumor necrosis factor-alpha (TNF-&agr;) density in the corneal epithelium was measured in all rats. Results: The mean numbers of TUNEL+ cells in the corneal epithelium and endothelium of rats in group 3 were 117.1 ± 23.8 and 34.6.± 11.3, respectively, whereas in group 4, they were 75.8 ± 15.7 and 14.7 ± 3.5, respectively. Also the mean TNF-&agr; densities in the corneal epithelium in group 3 and group 4 were 2.65 ± 1.3 and 1.65 ± 1.1, respectively. There was a significant decrease in the mean number of TUNEL+ cells in the corneal epithelium and endothelium and in the mean TNF-&agr; density in the corneal epithelium of rats in group 4, when compared with group 3. Conclusions: Topically applied AZM can decrease TNF-&agr;–induced apoptosis in corneal alkali burn.

Evaluation of choroidal thickness in patients with obstructive sleep apnea/hypopnea syndrome

Purpose: To compare the subfoveal choroidal thickness (SFCT) of patients with different severities of obstructive sleep apnea/hypopnea syndrome (OSAHS) and normal controls via enhanced depth imaging optical coherence tomography (EDI-OCT). Methods: In this retrospective, case-control study, 49 eyes from 49 patients that had undergone polysomnography were included. SFCT of the horizontal and vertical line scans were manually measured for all eyes based on EDI-OCT images. Two separate analyses were performed according to different apnea/hypopnea index (AHI) groupings. Initial testing was conducted using non-OSAHS, mild OSAHS (5≤AHI<15), moderate OSAHS (15≤AHI<30), and severe OSAHS (AHI≥30) patient groupings, while secondary testing used non-OSAHS, mild OSAHS (5≤AHI<15), and moderate/severe OSAHS (AHI≥15) patient groupings. Results: The mean SFCT was 314.5 μm in the non-OSAHS patients (n=14), 324.5 μm in the mild OSAHS patients (n=15), 269.3 μm in the moderate OSAHS patients (n=11), and 264.3 μm in the severe OSAHS patients (n=9). SFCT between the four groups revealed no significant differences despite a trend towards slight thinning in the severe group (P=0.08). When the moderate and severe groups were merged and compared with the mild OASHS and non-OSAHS groups, SFCT of the moderate/severe group was found to be significantly thinner than that of the mild group (P=0.016). A negative significant correlation was found between SFCT and AHI in OSAHS patients (r=0.368, P=0.033). Conclusions: In patients with moderate/severe OSAHS, EDI-OCT revealed a thinned SFCT. Other accompanying systemic or ocular diseases may induce perfusion and oxygenation deficiency in eyes of OSAHS patients. Further studies are required in order to determine the exact relationships between ocular pathologies and clinical grades of OSAHS.

Bacterial contamination of needles used for intravitreal injections: comparison between 27-gauge and 30-gauge needles.

Abstract Purpose: To compare the contamination rate between 27-gauge and 30-guage needles used for intravitreal injection (IVT). Methods: Patients undergoing IVT injections were enrolled prospectively. Injections were performed with 27- or 30-gauge needles. All needle tips were collected and placed in brain–heart infusion broth. The contamination rates of needles were compared. Results: A total of 109 patients participated in the study and a total of 126 IVT injections were performed. Injections were performed by 27-gauge (49%) and 30-gauge (51%) needle. No patient developed endophthalmitis. The overall contamination rate of the used needles were 13% for 27-guage and 29% for 30-guage (p = 0.022). However, this difference was nonsignificant after Bonferronis correction was applied. The most common bacteria isolated from the used needles are coagulase-negative Staphylococcus (CNS). Conclusion: The results suggest that the needle bore size seems not to be a risk factor for contamination during IVT injection.

Relationship between raised intraocular pressure and ischemia-modified albumin in serum and humor aqueous: a pilot study in rabbits

AIM We evaluated the relationship between increased intraocular pressure (IOP), ischemia-modified albumin levels in serum (IMA-s) and in humor aqueous (IMA-HA) in rabbits. METHODS Twenty-five albino New Zealand rabbits weighing between 2.0 and 2.8 kg were used in this pilot study. With permission from Canakkale Onsekiz Mart University Animal Ethics Committee, the IOP of both eyes of each rabbit were recorded with a Tonopen (Tono-Pen XL, Reichart Inc., Depew, NY, USA) after the application of topical proparacaine 0.5% HCl anesthesia. Blood (4 mL) was collected from the marginal ear vein and an intracameral injection of 2.3 mg/mL sodium hyaluronate and subconjunctival dexamethasone was given in the right eye. Anterior chamber aqueous fluid was obtained using a limbal approach with a 27 gauge needle from both eyes. The left eyes were used as controls. IOP was measured on the 1(st), 3(rd) and 10(th) day after the initial injection, with Tonopen, IMA-s levels and IMA-HA examined simultaneously. RESULTS Before the injections, IOP was 11.4±3.0 mm Hg in the right eye and 11.3±3.1 mm Hg in the left eye (P>0.05). There was a statistically significant difference between IMA-s levels before the IOP increase (IMA-s0) and IMA-s levels on the 1(st) and 3(rd) days after the increase in IOP (P=0.012 and P=0.01, respectively). No difference was observed between IMA-s0 and serum IMA levels on the 10(th) day (IMA-s10) after IOP increase (P=0.989). IMA-HA in the right eye in the first day after the injection was positively correlated with IOP (r=0.748; P=0.02). No other correlation is found between any other parameter with IMA-HA levels at any test time. A statistically significant positive correlation was observed between IMA-s values and IOP on the 1(st) and 3(rd) days (r=0.398, P=0.04 and r=0.382, P=0.04, respectively). There was no correlation between IMA-s levels and increased IOP on the 10(th) day after IOP increase (r=0.026, P=0.902). CONCLUSION IMA may be an important indicator of acute damage caused by diseases involving ischemic damage to the eye, especially in case of increased intraocular pressure.

Magnezyum: Kalsiyum kanal antagonisti olarak göz sağlığı üzerindeki etkileri

Magnesium is the physiologic calcium channel blocker, involving in many different metabolic processes by maintaining cell membrane function, modulating smooth muscle contraction and influencing enzymatic activities. Mag nesium has been shown to increase blood flow to tissues by modifying endothelial function via endothelin-1 (ET-1) and nitric Oxide (NO) pathways. Magnesium also exhibits neuroprotective role by blocking N-methyl-D-aspartate (NMDA) receptor related calcium influx and by inhibiting the release of glutamate, hence protects the cell against oxidative stress and apoptosis. Both increase in blood flow and its neuroprotective effect make magnesium a good candidate for glaucoma studies. Magnesium has been shown to decrease oxidative stress and apoptosis in retinal tissue and to have retinal ganglion cell sparing effect. A series of studies has been conducted about magnesium could decrease insulin resistance in diabetic patients, ease glycemia control and prevent diabetic retinopathy. Magnesium is found to be critically important in maintaining normal ionic homeostasis of lens. Magnesium deficiency has been shown to cause increased lenticular oxidative stress and ionic imbalance in the lens so trigger cataractogenesis. J Clin Exp Invest 2013; 4 (2): 244-251

The Effect of Smoking on Corneal Endothelial Cells

ABSTRACT Purpose: To investigate the effect of chronic cigarette smoking on the endothelial cells of the cornea via non-contact specular microscopy. Method: In this prospective, cross-sectional study, 25 eyes of 25 chronic smokers and 21 eyes of 21 age-matched, healthy non-smokers were enrolled. The Fagerström Test for Nicotine Dependence on Cigarettes was used to determine the nicotine dependency level. The level of cotinine, a major metabolite of nicotine, was measured in urine samples from the control group to detect whether they were passively affected by cigarette smoke. All participants underwent measurement of tear break-up time (TBUT), central corneal thickness (CCT), and axial length. Endothelial cell density and endothelial cell morphology were evaluated by non-contact specular microscopy. Results: On average, the cigarette smokers consumed 19.2 ± 8.3 cigarettes per day and had been smoking for 14.5 ± 6.8 years. The mean TBUT value was significantly lower in the smoker group compared to the non-smoker group (p < 0.05). No statistically significant difference was found in the mean CCT, mean endothelial cell density, or parameters of endothelial cell morphology between smokers and non-smokers. Conclusion: This study showed that cigarette smoking seems to affect the TBUT value but no effects were found on the parameters of corneal endothelial cells.