Serap Özden

Basal serum nitric oxide levels in patients with type 2 diabetes mellitus and different stages of retinopathy

PURPOSE To compare the basal serum levels of nitric oxide (NO) in patients with type 2 diabetes mellitus and different stages of diabetic retinopathy (DR) with the levels in nondiabetic control subjects. METHODS The 39 patients with type 2 diabetes included in this study were divided by stage of DR into 3 groups: group A, those without DR; group B, those with background/preproliferative DR; and group C, those with proliferative DR. Eleven nondiabetic subjects made up the control group (group D). The NO concentration was determined indirectly by measuring the serum level of nitrite (NO2-) plus nitrate (NO3-) (NOx = NO2- plus NO3-) using a spectrophotometric method based on the Griess reaction. RESULTS The patients with type 2 diabetes had significantly higher levels of serum NOx than the nondiabetic controls (p = 0.0001). In addition, the levels in the patients with proliferative DR were significantly higher (p = 0.002) than the levels in the patients with nonproliferative or no DR. CONCLUSION Our study demonstrated both elevated levels of serum NOx in diabetic patients as compared with nondiabetic controls and a relationship between NOx and DR severity. Hence, abnormal NO metabolism may have a role in the pathogenesis of DR.

Effect of Trimetazidine on Retinal Ischemia/Reperfusion Injury in Rats

Purpose: To investigate the effect of trimetazidine (TMZ), an antioxidant agent, on the ischemia/reperfusion (I/R) injury in rat retina histopathologically. Methods: The retinal I/R model was carried out by the 4-vessel occlusion method on Wistar albino rats. Twenty-one rats were divided into 7 groups, each comprising 3 rats. The animals in groups 1, 2 and 3 underwent 30 min of ischemia + 4 h of reperfusion and were treated by the administration of saline, TMZ before reperfusion and TMZ before ischemia, respectively. The animals in groups 4, 5 and 6 underwent 90 min of ischemia + 4 h of reperfusion and were treated in the same way as those in groups 1, 2 and 3, respectively. The 7th group was sham operated. Results: Thirty and 90 min of ischemia followed by 4 h of reperfusion induced retinal injury in the rat retina. Histopathologically, the inner plexiform and inner nuclear layers were the most affected parts. TMZ was able to reduce almost all retinal I/R damage when administered before ischemia. A cytoprotective effect of TMZ was partly observed in those animals which were treated before reperfusion. Conclusion: TMZ seemed to have a protective effect against retinal I/R injury in rats.

Orbital color Doppler imaging in Behçet’s disease with or without ocular involvement

PurposeTo investigate the value of color Doppler imaging (CDI) of orbital vasculature in the assessment of ocular involvement in patients with Behçet’s disease (BD) without clinical ophthalmologic abnormalities.MethodsCDI of the orbital vessels were performed on 26 eyes of 13 patients who were diagnosed as having BD with ocular involvement (group 1), 65 eyes of 33 patients who had BD without ocular involvement (group 2) and 40 eyes of 20 healthy volunteers (group 3). Peak systolic (PSV) and end-diastolic (EDV) blood flow velocities and resistivity index (RI) measurements were obtained for the ophthalmic artery (OA) and central retinal artery (CRA). The mean velocity of the central retinal vein (CRV) was also measured.ResultsFor the OA, PSV and EDVs were significantly lower and RIs were significantly higher in group 2 than in control subjects. In group 1, only the EDVs of OA were significantly lower than in healthy subjects. For the CRA, PSV and EDVs were significantly lower, and RIs were significantly higher in both BD groups than those in group 3. When group 1 and group 2 were compared, the differences between PSV, EDV and RI measurements for the CRA and OA were statistically insignificant. There was no significant difference in blood flow velocity of the CRV between the three groups.ConclusionMajor hemodynamic changes were observed in the ophthalmic vasculature of Behçet’s patients with or without ocular involvement by CDI. CDI may detect ocular blood flow alterations before initial clinical manifestations.

Effects of intraoperative sponge mitomycin C and 5-fluorouracil on scar formation following strabismus surgery in rabbits

purpose To investigate the influence of 5-fluorouracil (5-FU) and mitomycin C (MMC) on the postoperative adhesions following strabismus surgery in rabbits. methods Twenty-one New Zealand white rabbits were used in this prospective, masked, controlled trial. Both eyes of 20 animals underwent 3-mm recession of the superior rectus muscle (SRM). In group I (10 animals), one eye of each animal received topical application of MMC (0.2 mg/ml) for 5 minutes and the other eye (control eye) was treated with balanced salt solution (BSS) using an intraoperative sponge. In group II (10 animals), a randomly chosen eye of each animal was treated with 5-FU soaked sponges (50 mg/ml) for 5 minutes and the fellow eye (control eye) with BSS. Two eyes of a rabbit were included as unoperated controls. Four weeks after the surgery, conjunctival vascularity and postoperative adhesions between the SRM Tenons capsule (TC) and SRM sclera (scl) were assessed. Additionally, eyes were enucleated and evaluated histopathologically for evidence of scarring, granuloma formation, and muscle tissue changes under a light microscope. results MMC-treated eyes had a higher rate of avascular conjunctiva compared to both controls and 5-FU-treated eyes. Mean adhesion scores, particularly between the SRM-scl, were lower in eyes treated with antiproliferative agents compared to controls. The difference was statistically significant in MMC-treated eyes for the adhesions between SRM-scl (p = 0.03). Histopathological examination revealed less scarring and granuloma formation in MMC- and 5-FU-treated eyes compared to their control eyes. conclusions MMC, and to a lesser extent 5-FU, are shown to be effective in reducing postoperative scarring following strabismus surgery in rabbits. It seems reasonable to suggest that antimetabolites should be used for cases having an increased risk of postoperative adhesions.

Subjective Visual Experience and Pain Level during Phacoemulsification and Intraocular Lens Implantation under Topical Anesthesia

Purpose: To investigate the subjective visual experiences and pain during the phacoemulsification and intraocular lens (IOL) implantation under topical anesthesia, and whether these parameters change according to the stage of phacoemulsification cataract surgery. Methods: Forty eyes of 40 patients with cataract undergoing phacoemulsification and IOL implantation under topical anesthesia were included in this study. The patients were told that they would be asked about their visual experiences and pain level, if any, during every stage of the surgery. As for degree of the pain, a 5-grade scale was used. The surgery was divided into 9 stages, i.e., clear corneal incision, continuous curvilinear capsulorhexis, side-port incisions at 3 and 9 o’clock positions, hydrodissection, nuclear rotation, phacoemulsification, bimanual irrigation and aspiration, IOL implantation, apposition of corneal incisions with stromal hydration. Results: All subjects (100%) reported that they had seen some kind of light during the operation. Thirty-eight patients (95%) said that they had seen one or more colors. In 32 patients (80%), the light intensity decreased, and colors blurred significantly following the hydrodissection. As for the pain level during surgery, the overall pain score was found to be 0.40. The highest mean pain score was noted during IOL implantation stage followed by phacoemulsification and bimanual irrigation-aspiration. Conclusion: Topical anesthesia is both a safe and effective method for small-incision clear corneal phacoemulsification cataract surgery. Patients may experience visual sensations, and the pain felt during the operation is low and tolerable. Visual experiences and pain level may change according to the stage of phacoemulsification cataract surgery.

Efficacy and Safety of Rimexolone 1% Versus Prednisolone Acetate 1% in the Control of Postoperative Inflammation Following Phacoemulsification Cataract Surgery

Purpose: The aim of this study was to evaluate the efficacy and safety ofrimexolone 1% ophthalmic suspension compared to that of 1% prednisoloneacetate in the control of inflammation in eyes undergoing cataract extraction withphacoemulsification followed by posterior chamber intraocular lens implantation.Methods: Forty-eight patients who underwent uncomplicated cataract extraction with phacoemulsification followed by posterior chamber IOL implantation constituted the study group of this prospective, randomized, double-masked investigation. Patients were randomly assigned to two treatment groups; rimexolone 1% ophthalmic suspension (27 subjects) or prednisolone acetate 1% (21 subjects). Postoperatively, patients used topical rimexolone or prednisolone drops four times a day for 15 days. Patients were examined at the first postoperative day (day 1), and days 3, 7 and 15. The major efficacy parameters assessed clinically on each visit were anterior chamber cells, anterior chamber flare and conjunctival hyperemia. Safety of the rimexolone was evaluated by IOP values and the presence of adverse effects.Results: Regarding all three efficacy parameters, rimexolone was found to be clinically and statistically equivalent to prednisolone acetate. Intraocular pressure values during the postoperative period were also similar in both groups.Conclusion: Rimexolone 1% ophthalmic suspension is both an effective and safe topical steroid in controlling postoperative inflammation after cataract extraction with phacoemulsification.

Protective effect of ischemic preconditioning on retinal ischemia-reperfusion injury in rats

BACKGROUND A short period of ischemia can induce remarkable tissue resistance to the deleterious effects of subsequent ischemia and reperfusion. We performed a study to investigate the effect of ischemic preconditioning on retinal ischemia-reperfusion injury in rats. METHODS Ten Wistar albino rats were divided into two groups of five animals (10 eyes): one group underwent 5 minutes of ischemic preconditioning (achieved by clamping the common carotid arteries at the time of vertebral artery cauterization), and the other did not (control group). In both groups, the vertebral arteries were occluded bilaterally with an electric needle coagulator under an operating microscope. Forty-eight hours later the rats were reanesthesized, and both common carotid arteries were clamped to interrupt blood flow. The duration of ischemia was 30 minutes. The clamp was then removed to enable reperfusion for 4 hours. The animals were killed by decapitation, and retinal sections were evaluated under light and electron microscopy. The signs of ischemia-reperfusion injury (cellular degeneration, vacuolization between retinal layers, increase in retinal thickness due to edema, mononuclear cell infiltration and apoptotic cell count) were recorded. RESULTS Light microscopy of retinal sections from rats in the ischemic preconditioning group showed a well-preserved retinal structure. The mean thickness values (and standard deviation [SD]) for the inner nuclear layer (104.0 microm [2.54 microm] vs. 49.0 microm [ 10.83 microm]) and inner plexiform layer (134.8 microm [10.13 microm] vs. 88.5 microm [17.46 microm]) were significantly higher in the control group than in the preconditioning group (p = 0.009), indicating increased retinal thickness in the former group due to tissue edema resulting from ischemia-reperfusion injury. The mean mononuclear cell count (6.67 [SD 1.97] vs. 2.5 [SD 1.0]) and apoptotic cell count (18.2 [SD 5.7] vs. 5.3 [SD 1.0]) were significantly higher in the control group than in the preconditioning group (p = 0.002), indicating an inhibitory effect of ischemic preconditioning on leukocyte infiltration and apoptotic cell death. INTERPRETATION Ischemic preconditioning attenuated ischemia-reperfusion injury in the rat retina.

Protective effects of antithrombin III on retinal ischemia/reperfusion injury in rats : A histopathologic study

PURPOSE To investigate the effect of antithrombin III (AT III) on retinal ischemia/reperfusion (I/R) injury in rats. METHODS The study was carried out on 10 Wistar albino rats (20 eyes) and four-vessel occlusion method was employed to induce retinal ischemia in this study. Rats were divided into two groups: Group I (control group, 10 eyes) and Group II (AT III, 10 eyes). In both groups, vertebral arteries were occluded bilaterally an electric needle coagulator under an operating microscope. A total of 48 hours after the initial procedure, the rats were re-anesthetized and both common carotid arteries were clamped to interrupt blood flow. In Group II, rats were injected intravenously with 250 U/kg of AT III 5 minutes before the induction of ichemia. Duration of ischemia was 30 minutes. At the end of this period, clamp was removed for the reperfusion of the eye for 4 hours. Following the reperfusion period, the animals were killed by decapitation. Retinal sections were evaluated under light and electron microscope. The signs of I/R injury at the microscopic level, i.e., cellular degeneration, vacuolization between retinal layers, increase in the retinal thickness due to edema, mononuclear cell infiltration, and apoptotic cells, were recorded for each group. RESULTS Retinal sections obtained from the rats in the AT III group revealed a well preserved retinal structure. When average thickness values of the two groups were compared to each other, the difference was significant with respect to inner nuclear and inner plexiform layers indicating increased retinal thickness values in Group I due to tissue edema resulting from I/R injury. Similarly, mononuclear cell infiltration and apoptotic cell counts were found to be significantly higher in control group compared to AT III group showing the inhibitory effect of AT III on leukocyte infiltration and apoptotic cell death in rat retina. CONCLUSIONS Antithrombin III attenuated I/R injury in rat retina.

The Effect of Tilted Disc Syndrome on Ocular Hemodynamic Measurements

Background: The purpose of this study was to assess ocular hemodynamics in patients with unilateral tilted disc syndrome (TDS) using color Doppler ultrasonography (CDUS). Methods: Fifteen consecutive patients with unilateral TDS and normal-appearing contralateral optic nerves were enrolled. Both eyes of all participants underwent detailed ophthalmological examination including automated visual field testing. CDUS was performed in the eyes with tilted discs and fellow unaffected eyes. Peak systolic velocities, end diastolic velocities, and vessel resistance were measured in the ophthalmic artery (OA), central retinal artery (CRA), nasal posterior ciliary artery (NPCA), and temporal posterior ciliary artery (TPCA). The minimum and maximum blood flow velocities were also measured in the central retinal vein (CRV). Results: No statistically significant differences were found between eyes with tilted discs and fellow normal eyes in terms of OA, CRA, NPCA, or TPCA mean peak systolic or end diastolic velocities, resistivity indices, and the mean maximal and minimal CRV blood flow velocities. Conclusion: Ocular hemodynamic measurements determined by CDUS do not appear to be altered in tilted disc syndrome.

Subtelomeric 6p monosomy and 12q trisomy in a patient with a 46,XX,der(6)t(6;12)(p25.3;q24.31) karyotype: Phenotypic overlap with Mutchinick syndrome.

We report on a patient with partial monosomy 6p and partial trisomy 12q identified by fluorescent in situ hybridization (FISH) and array‐based comparative genomic hybridization (aCGH). She had a complex phenotype characterized by mental retardation (MR), psychomotor developmental delay, speech disorder, hypertelorism, eye anomalies, hearing loss, low‐set malformed ears, thin upper lip, heart defect, clinodactyly, pes valgus, and skeletal anomalies. There is phenotypic overlap between our case and Mutchinick syndrome. This is the first report of a combined partial monosomy 6p and partial trisomy 12q due to an unbalanced translocation between subtelomeric regions of these chromosomes.