Orhan Ates

Oxidative DNA damage in patients with cataract

Acta Ophthalmol. 2010: 88: 891–895

Conjunctival Flora in Patients With Type 1 or Type 2 Diabetes Mellitus

Patients with diabetes mellitus (DM) are prone to infection because glucose in the skin, urine, mucous membranes, and tears promotes growth of microorganisms. Conjunctival flora develops soon after birth, and some saprophytic conjunctival flora play a pathogenic role when immune function is compromised, which can lead to serious infection. DM is one condition that may compromise immune status. In lacrimal function tests of DM patients, a decrease in breakup time (BUT) of lacrimal film and a decrease in Schirmer’s test results were seen. In the present study, conjunctival flora in patients with DM was compared with that in controls with regard to type and duration of diabetes and results of lacrimal function tests. Seventeen patients with type 1 DM (n=34 eyes), 66 patients with type 2 DM (n=132 eyes), and 50 control subjects (n=100 eyes) were included. The control group consisted of age-matched patients with no ophthalmologic problems other than refractive error. Clycosylated hemoglobin values were measured with highpressure liquid chromatography with the Hi-AUTOA1c analyzer (Kyoto Daiichi Kagatu Co., Ltd., Kyoto, Japan). Type and duration of diabetes and demographic data were recorded, and routine ophthalmologic examinations were performed; the BUT of lacrimal film was determined, and the results of Schirmer’s test were assessed. Microbiologic sampling was performed twice for both eyes with sterile cotton swabs. One sample was incubated in 2 mL of brain-heart infusion broth agar; the other was incubated for the presence of fungi in Sabouraud dextrose agar. Colony morphology, hemolysis, and Cram’s stain, as well as catalase, oxidase, and coagulase tests were performed. No growth was observed in 12 of 1 7 patients (35.4%) with type 1 DM, 28 of 66 patients (21.2%) with type 2 DM, and 25 of 50 control subjects (50%).Staphylococcus epidermidis (11.79%) andStaphylococcus aureus (11.7%) were the most frequently isolated organisms in the type 1 DM group, and Sepidermidis (24.2%) and Saureus (21.2%) were the predominant organisms in the type 2 DM group. In control subjects, Sepidermidis (22%), Saureus (12%), andCorynebacterium spp (10%) were the most frequently isolated organisms, and the number of eyes with growth of Saureus was significantly higher in the type 2 DM group than in the other groups (P<.01). Patients with diabetes are more prone to postoperative endophthalmitis than are nondiabetics, and preoperative application of antiseptic or antimicrobial agents to the conjunctiva may not sterilize the area. Impaired integrity of the posterior capsule may also increase the risk of endophthalmitis. Postoperative endophthalmitis is usually associated with gram-positive organisms (75%–80%); gram-negative organisms (15%–29%) and fungi (3%–13%) account for a smaller number of cases. A high rate of resistance to penicillin, ampicillin, and tetracycline was observed in Saureus isolates, although resistance to vancomycin was absent, rendering this molecule the most effective therapeutic option. In this study, Sepidermidis and Saureus were the 2 most frequently isolated organisms in patients with DM. It is concluded that the conjunctival flora in diabetic subjects differs from that in nondiabetic subjects. This should be considered preoperatively and postoperatively, and prophylactic and postoperative treatment should be administered accordingly to diabetic patients.

Oxidative DNA damage in retinopathy of prematurity

Purpose This study examines the levels of oxidative damage in patients with retinopathy of prematurity (ROP). Methods Fifty patients were recruited with a birthweight below 1500 g or gestational age below 32 weeks. The cases were classified into those who developed ROP (n=25) and those without ROP (n=25). The authors obtained blood and urine samples from each infant, for measuring 8-hydroxy 2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) levels, at the time of the first examination at 4–6 postnatal weeks. Results A significant difference was observed in leukocyte and urine 8-OHdG levels in patients with ROP compared to those without ROP (p<0.001 for both). Similarly, a significant difference was observed in plasma and urine MDA levels in patients with ROP compared to those without ROP (p<0.001 for both). In addition, significant correlations were found between levels of 8-OHdG in leukocyte DNA and plasma MDA (r=0.859, p<0.001), and between levels of urine 8-OHdG excretion and urine MDA (r=0.563, p<0.001). Conclusions 8-OHdG in leukocyte DNA and urine levels in premature infants can be useful as an indicator for ROP screening.

Comparison of the Efficacy of Topical N-Acetyl-Cysteine and a Topical Steroid-Antibiotic Combination Therapy in the Treatment of Meibomian Gland Dysfunction

PURPOSE This study aimed to compare the efficacy of topical N-acetyl-cysteine (NAC) with a topical steroid-antibiotic combination, betamethasone-sulfacetamide sodium therapy in patients with meibomian gland dysfunction (MGD). METHODS Twenty patients with MGD were prospectively randomized and assigned into 2 groups. The patients were instructed to use either NAC 5% or a topical steroid-antibiotic combination, betamethasone 0.1%-sulfacetamide sodium 10%, topically 4 times a day for a month. All patients were instructed to apply lid hygiene once daily. RESULTS One month of topical therapy provided statistically significant improvements in fluorescein break-up time and Schirmer scores as compared with the initial study visit in both groups (P≤0.001). Significant improvements for the symptoms of ocular burning, itching, and intermittent filmy or blurred vision were noted in both groups at 1 month as compared with 1 day (P<0.05). Considering these rates, there was no significant difference between the groups (P>0.05). None of the patients developed an allergic reaction to the medications, and intraocular pressure measurements were within the normal limits in both groups. CONCLUSION When used in conjunction with eyelid hygiene, topical administration of NAC appears to be as effective as a topical steroid-antibiotic combination, betamethasone-sulfacetamide sodium therapy in patients with MGD.

Plasma coenzyme Q10 levels in type 2 diabetic patients with retinopathy.

AIM To determine the relationship between proliferative diabetic retinopathy (PDRP) and plasma coenzyme Q10(CoQ10) concentration. METHODS Patients with type 2 diabetes and PDRP were determined to be the case group (n=50). The control group was consist of healthy individuals (n=50). Plasma CoQ10 and malondialdehyde (MDA) levels were measured in both groups. RESULTS Ubiquinone-10 (Coenzyme Q10) levels in PDRP and control subjects are 3.81±1.19µmol/L and 1.91±0.62µmol/L, respectively. Plasma MDA levels in PDRP and control subjects were 8.16±2µmol/L and 3.44±2.08µmol/L, respectively. Ratio of Ubiquinol-10/ubiquinone-10 in PDRP and control subjects were 0.26±0.16 and 1.41±0.68, respectively. CONCLUSION The ratio of ubiquinol-10/ubiquinone-10 is found lower in patients with PDRP. High levels of plasma ubiquinol-10/ubiquinone-10 ratio indicate the protective effect on diabetic retinopathy.

Agmatine as retinal protection from ischemia-reperfusion injury in guinea pigs

PurposeTo determine the neuroprotective effect of agmatine (Agm) on the retinas of guinea pigs subjected to a transient ischemia-reperfusion insult.MethodsTwenty-eight guinea pigs were randomly divided into four groups. Forty-five minutes before ischemic insult, the guinea pigs were intraperitoneally administered either Agm (50 mg/kg) (Agm 1) or saline (control 1 group) once, or twice separated by a 12-h interval (Agm 2; control 2). Transient ocular ischemia was achieved under general anesthesia by cannulating an anterior chamber maintainer connected to an infusion line of a semiflexible bottle. The saline reservoir pressure was increased by using a blood pressure tolls cuff to achieve an intraocular pressure (IOP) of 150 mmHg. This IOP was maintained for 90 min. Reperfusion was achieved by pulling off the anterior chamber maintainer. The animals in the Agm 1 and control 1 groups were killed at the end of the 4-h reperfusion period. The eyes were enucleated for histopathological (retinal thickness) and biochemical (thiobarbituric acid reactive substance, TBARS, and nitric oxide, NO) investigation. The animals in the Agm 2 and control 2 groups were killed at the end of a 24-h reperfusion period.ResultsThe mean retinal thickness of the animals in the Agm 1 (25.94 ± 1.23 μm) and Agm 2 (24.49 ± 0.88 μm) groups was lower than that of those in the control 1 (37.60 ± 2.27 μm) and control 2 (36. 64 ± 1.32 μm) groups (P < 0.05). The mean TBARS level of the animals in the Agm 1 (8.37 ± 0.94 nmol/ml) and Agm 2 (8.01 ± 0.97 nmol/ml) groups was lower than that of those in the control 1 (12.09 ± 1.27 nmol/ml) and control 2 (12.09 ± 1.27 and 11.72 ± 1.63 nmol/ml) groups (P < 0.05). The mean NO level of the animals in the Agm 1 (100.77 ± 6.20 nmol/ml) and Agm 2 (94.63 ± 5.24 nmol/ml) was lower than that of those in the control 1 (131.77 ± 4.61 nmol/ml) and control 2 (122.43 ± 4.35 nmol/ml) groups (P < 0.05). There were positive correlations between the TBARS and NO levels and retinal thickness in the Agm and control groups.ConclusionAgmatine exerts a significant neuroprotective effect on guinea pig retinas after transient ischemia-reperfusion insult.

Retinal Nerve Fiber Layer Thickness in Early-Stage Diabetic Retinopathy With Vitamin D Deficiency.

PURPOSE To evaluate retinal nerve fiber layer (RNFL) thickness in early-stage diabetic retinopathy (DR) patients with and without vitamin D deficiency (VDD). METHODS This study compared 50 early-stage DR patients with VDD (group 1) and 50 early-stage DR patients without VDD (group 2). All patients were examined by the same ophthalmologist. Mean RNFL thickness was determined by optical coherence tomography (OCT) performed by the two independent ophthalmologists for all subjects. Vitamin D levels were measured by using a radioimmunoassay. Vitamin D deficiency was defined, in accordance with the general standards, as a 25-hydroxyvitamin D (25(OH)D) level lower than 20 ng/mL. RESULTS There were no significant differences between the groups in terms of age and sex distribution (P > 0.05). The mean serum 25(OH)D concentration of group 1 was significantly lower than that of group 2 (P < 0.001). The mean RNFL thickness of group 1 was significantly reduced compared to that of group 2 (P < 0.001). A significant relationship between the mean RNFL thickness and serum 25(OH)D concentrations was observed in group 1 (P < 0.001). CONCLUSIONS The results indicate that vitamin D functions as a neuroprotective component for optic nerves. Low serum 25(OH)D concentrations contribute to RNLF thinning in early-stage DR patients with VDD.

evaluation of cardiovascular biomarkers in patients with age-related wet macular degeneration

Aim To evaluate levels of homocysteine, asymmetric dimethylarginine (ADMA), and nitric oxide (NO), as well as activity of endothelial NO synthase (eNOS), in patients with age-related macular degeneration (AMD). Methods The levels of homocysteine, ADMA, and NO and activity of eNOS in patients who were diagnosed with wet AMD by fundus fluorescein angiography (n=30) were compared to a control group with no retinal pathology (n=30). Results Levels of homocysteine and ADMA were found to be significantly higher in the wet AMD group than in the control group (P<0.001), whereas NO levels and eNOS activity were higher in the control group (P<0.001). In the wet AMD group, we detected a 2.64- and 0.33-fold increase in the levels of ADMA and homocysteine, respectively, and a 0.49- and 2.41-fold decrease in the eNOS activity and NO level, respectively. Conclusion Elevated levels of homocysteine and ADMA were observed in patients with wet AMD. Increased ADMA may be responsible for the diminished eNOS activity found in these patients, which in turn contributes to the decrease in NO levels, which likely plays a role in the pathogenesis of AMD.

Carbonic Anhydrase Activities from the Rainbow Trout Lens Correspond to the Development of Acute Gas Bubble Disease

Dissolved gas supersaturation is hazardous to fish and can result in gas bubble disease (GBD). Signs of GBD typically include bubbles in the eyes, fins, skin, lateral line, and gill filaments. Ocular abnormalities in diseased salmonids typically occur after aberrant gas production in the eyes. In this study, freshwater rainbow trout Oncorhynchus mykiss were exposed experimentally to percent total gas pressure (TGP%) levels of 104% (control) and 115%. No mortalities occurred during the 7-d experimental period. Effects of GBD were observed externally as a darkened skin, exophthalmia, localized hemorrhage in the eye, and gas bubbles on the operculum. Additional signs included increased swimming activity and, more frequently, panic episodes. Carbonic anhydrase (CA) enzyme activities from the lens and retina were determined at days 0, 1, 3, 5, and 7 of the study. Venous blood gases were also measured on day 7. Retinal pH did not differ between normal and affected fish, but blood characteristics such as the partial pressure of O2, partial pressure of CO2, carboxyhemoglobin level, and bicarbonate ion concentration were significantly elevated in affected fish relative to normal fish. Venous blood pH and oxyhemoglobin levels were not significantly different between affected and normal fish. Patterns of response to total dissolved gas levels differed between the lens and the retina. Mean CA activities in the lenses of fish exposed to a TGP% level of 115% were significantly below those of control fish. However, retinal CA activities did not significantly differ between the two groups over the course of the experiment. These findings show that dissolved gas supersaturation reduces CA activity in the rainbow trout lens.

Intravitreal Infliximab Injection to Treat Experimental Endophthalmitis

Objective The purpose of this study was to compare the use of an intravitreal injection of infliximab and of dexamethasone combined with vancomycin to treat experimental endophthalmitis induced by Staphylococcus epidermidis. Materials and Methods The study was conducted between March 25 and April 13, 2012. Twenty-five six-month-old healthy rabbits were used, each weighing 2.5-3 kg. The rabbits were randomized into five groups with five animals per group. Endophthalmitis was induced by 0.1 mL (103 colony-forming units) S. epidermidis in all groups. In group 1, injection was not implemented after the occurrence of endophthalmitis. In groups 2, 3, and 4, the following intravitreal injections were given 24 h after the occurrence of endophthalmitis: group 2, 0.1 mg/0.1 mL vancomycin; group 3, 1 mg/0.1 mL vancomycin and 1 mg/0.1 mL dexamethasone; and group 4, 1 mg/0.1 mL vancomycin and 2 mg/0.1 mL infliximab. Group 5 was the control/uninfected group. The rabbits were clinically assessed each day for seven days. On day 9, a histopathologic evaluation was performed after enucleation. Results After a clinical evaluation, no statistically significant difference was found between the vancomycin+infliximab and vancomycin+dexamethasone groups (p>0.05). The difference was significant when both groups were compared with the vancomycin group (p<0.001). After the histopathologic evaluation, no statistically significant difference was found among the three groups (p>0.05). Conclusion An intravitreal injection of infliximab and of dexamethasone combined with vancomycin have similar clinical and histopathologic effects. To supplement the antibiotic treatment of endophthalmitis, infliximab in a safe dose range can be used as an alternative to dexamethasone to suppress inflammation and prevent ocular damage.