Ahmet Satici

The role of oxidative stress in diabetic retinopathy

Purpose To investigate the role of oxidative stress in the development of diabetic retinopathy.Methods This study included 25 patients with diabetic retinopathy (group 1), 34 patients with non-insulin-dependent diabetes mellitus without any angiopathy complications (group II) and 26 healthy subjects (group III). The serum malondialdehyde (MDA)-like metabolite levels as an index of lipid peroxidation, the erythrocyte glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and serum vitamin C levels of the patients and healthy subjects were measured.Results The mean serum concentration of MDA-like metabolites of patients in group I was 4.38 ± 1.31 nmol/ml, in group II was 3.38 ± 0.95 nmol/ml and in group III was 2.61 ± 0.85 nmol/ml. There were significant differences between the groups (p = 0.001 for group I compared with group II, p = 0.0001 for group I compared with group III and p = 0.002 for group II compared with group III). There was a significant correlation between the serum lipid peroxidation concentrations and duration of the disease (r = 0.36, p = 0.047). The mean erythrocyte GSH-Px and SOD levels of group I were respectively 68.97 ± 18.04 and 1597.78 ± 296.46 U/g Hb, of group II were 64.30 ±19.26 and 1581.33 ± 278.08 U/g Hb, and of group III were 65.52 ± 17.58 and 1587.44 ± 281.17 U/g Hb. There were no significant differences among the antioxidant enzyme levels in the three groups (p > 0.05). The mean serum vitamin C level in group I was 42.72 ± 8.90 μmol/l, in group II was 49.26 ± 11.52 μmol/l and in group III was 58.57 ± 9.75 μmol/l. There were significant differences among the mean serum vitamin C levels of the three groups (p = 0.02 for group I versus group II p = 0.001 for group I versus group III and p = 0.002 for group II versus group III).Conclusions Free radicals forming in diabetes mellitus and increasing over time may play a role in the development of diabetic retinopathy, which is an important complication of the disease.

A Survey of Trachoma: The Histopathology and the Mechanism of Progressive Cicatrization of Eyelid Tissues

The aim of this study is to demonstrate the spectrum of conditions encompassed by the term ‘trachomatous cicatrization of eyelid tissue’, to discuss the mechanisms of scar tissue formation and to describe sequelae in this potentially blinding condition. Specimens of eyelid tissues were taken from 27 upper eyelids of 21 patients with entropion who underwent surgical procedures and 2 post-mortem upper eyelids with severe trachomatous entropion. Upper palpebral conjunctival swabs and biopsy specimens were taken from 5 patients with active trachoma and they were examined by fluorescence microscopy and routine histopathological methods. Conjunctival impression cytology samples were collected in all patients. In specimens taken from patients with active trachoma the inflammatory infiltrate was organized as lymphoid follicles in the underlying stroma and impression cytology showed cytoplasmic elementary bodies. In specimens taken from patients with scarring trachoma light microscopy studies showed subepithelial fibrous membrane formation, squamous metaplasia and loss of goblet cells, pseudogland formation in conjunctiva, degeneration of orbicularis oculi muscle fibres, subepithelial vascular dilatation, localized perivascular amyloidosis and subepithelial lymphocytic infiltration. Accessory lachrymal glands and the ducts of glands were compromised by subepithelial infiltration and scarring. The contraction of the subepithelial fibrous tissue formed by collagen fibres and anterior surface drying are the main factors contributing to the chronic cicatrization and entropion formation.

Increase of free oxygen radicals in aqueous humour induced by selective Nd:YAG laser trabeculoplasty in the rabbit

Purpose To investigate the impact of selective Nd:YAG laser trabeculoplasty on free oxygen radicals and antioxidant enzymes of the aqueous humour in the rabbit. Methods One eye of 18 rabbits was subjected to 360° selective laser trabeculoplasty (LT) with a frequency-doubled Nd:YAG laser (532 nm). The anterior chamber aqueous humour was aspirated 3, 12 hours and 1, 3, 7, 10 days after treatment. Lipid peroxide (LPO) and glutathione S transferase (GST) levels and superoxide dismutase (SOD) activities of aqueous humour were measured. Results Concentrations of LPO in the aqueous humour of the treated eyes were significantly higher than the untreated eyes until the 7th day. Aqueous SOD activity significantly decreased 3 hours after LT and remained low until day 7. Aqueous GST levels were significantly decreased between 12 hours and 7 days after the LT. Conclusions Selective LT was followed by an immediate increase in the aqueous humour LPO concentration and decreases of SOD and GST in the rabbit, probably due to photo-vaporization and photodisruption caused by the frequency- doubled Nd:YAG laser. The increased aqueous LPO levels suggest that free oxygen radicals are formed in the pigmented trabecular meshwork during LT, and may be responsible for the inflammatory complications of this procedure.

Malondialdehyde and antioxidant enzyme levels in the aqueous humor of rabbits in endotoxin-induced uveitis.

Purpose To investigate the role of oxidative stress in endotoxin-induced uveitis. Methods Lipopolysaccharide was injected intravitreally into the right eyes of rabbits. Sterile saline was injected intravitreally into the left eyes as a control. Inflammation was assessed according to clinical score, aqueous humor cell count, and protein levels. Malondialdehyde, superoxide dismutase, glutathione peroxidase, catalase, and nitrite levels were measured in the aqueous humor. Results The clinical grade (p<0.01), inflammatory cell count (p<0.001), and protein content (p<0.001) were significantly higher in the aqueous humor of eyes with uveitis than in that of controls. Malondialdehyde (p<0.01) and nitrite (p<0.001) levels in the aqueous humor of eyes with uveitis were significantly higher than in the control group. Superoxide dismutase (p<0.001), glutathione peroxidase (p<0.001), and catalase (p<0.001) levels were significantly lower in the aqueous humor of eyes with uveitis than in that of the controls. Conclusions Oxygen free radicals may be implicated as a mediator of inflammation in endotoxin-induced uveitis. The increase in free radicals in the aqueous humor may play a role in the pathogenesis of endotoxin-induced uveitis.

The Effects of Bupivacaine and Lidocaine on the Corneal Endothelium when Applied into the Anterior Chamber at the Concentrations Supplied Commercially

Purpose: To investigate the direct toxic effects of bupivacaine HCl 0.5% and lidocaine HCl 2%, two commonly used injectable local anesthetic agents, on the corneal endothelium when applied intracamerally. Methods: Two groups were formed, each consisting of 12 pigmented rabbits, and 0.2 ml of the anesthetic agent were injected intracamerally into the right eyes. The central corneal thicknesses and corneal clarities were evaluated preoperatively and at 3, 6, 9, 12 h and 1, 3, 7 days postoperatively. While the central corneal thicknesses were evaluated by ultrasonic pachymetry, the corneal opacification scored between 0 and 3 was assessed by biomicroscopic examination and photographs. Results: Both bupivacaine and lidocaine caused corneal thickening in the 3- to 12-hour measurements. In addition, there was significant corneal opacification in both groups in the 3-hour and 3-day measurements. The corneal thickening and corneal opacification determined during 3- and 6-hour measurements in the eyes which received intracameral bupivacaine were significantly higher than those determined in the lidocaine-injected group. In both groups, the corneal thickness and corneal clarity scores returned to the preoperative values on the 1st and 7th days, respectively. Conclusions: When applied into the anterior chamber at the concentrations supplied commercially, both bupivacaine and lidocaine cause statistically significant corneal thickening and clinically significant corneal opacification. It should be noted that the injection of these agents into the anterior chamber during the operation at the concentrations supplied commercially may be a potential risk factor for endothelial injury.

The treatment of severe trachomatous dry eye with canalicular silicone plugs.

Purpose To evaluate the effects of temporary canalicular occlusion with silicone plugs on trachomatous dry eye patients who were on maximal tolerable medical therapy.Methods Forty-four trachomatous dry eye patients who had Schirmer testing with topical anaesthetic measuring 5 mm or less and a tear film break-up time of 5 s or less were included. After the lacrimal efficiency test with dissolvable collagen punctal plugs, silicone canalicular plugs were placed in 22 trachomatous dry eye patients. The other 22 patients in the untreated control group were allowed to continue their medical therapy. Pretreatment and post-treatment evaluations included subjective patient assessment, rose Bengal and fluorescein staining, tear film break-up time, Schirmer testing, conjunctival impression cytology and goblet cell counting.Results Six months after plug placement, 18 eyes (82%) of 22 patients had subjective improvement and all these patients successfully wore plugs for at least 6 months. There were statistically significant differences between the pretreatment and post-treatment test results including rose Bengal and fluorescein staining scores, tear film break-up times and Schirmer testing measurements. Impression cytology showed improvement of squamous metaplasia in 17 eyes (77%). Eight of the patients (36%) were able to decrease dependency on topical therapy. Ten of the patients (45%) completely stopped using artificial tears. There were statistically significant differences between the two groups in the total symptom scores, staining scores, tear film break-up time, Schirmer testing, impression cytology scores and goblet cell counts.Conclusion In cases where topical tear supplementation is insufficient to relieve the signs and symptoms of severe dry eye and the lacrimal puncta have not already been closed by the trachomatous cicatrising process, occlusion of the canaliculi may be useful to prevent drainage of both natural and artificial tears. Canalicular occlusion improves the objective signs and subjective symptoms and may significantly decrease dependency on tear supplements in selected patients.

Efficacy of topical cyclosporine A in the treatment of severe trachomatous dry eye.

Purpose:  The purpose of this study was to evaluate the efficacy of topical cyclosporine A (CsA) treatment in patients with severe trachomatous dry eye.

Relationship between Tear TNF-α, TGF-β1, and EGF Levels and Severity of Conjunctival Cicatrization in Patients with Inactive Trachoma

Tear tumor necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), and epidermal growth factor (EGF) levels were determined in patients with inactive trachoma, and a possible relation between these cytokines and conjunctival cicatrization severity was investigated. Forty-four patients with inactive trachoma who were admitted to the Department of Ophthalmology at the Harran University, Sanliurfa, Turkey, were included in this study. The control group consisted of 20 age- and sex-matched healthy subjects. The levels of cytokines in tears were measured by ELISA. Tear samples were collected from the conjunctival cul-de-sac by means of blunted-tip glass capillary tubes. Eyes with inactive trachoma were classified into three subgroups with respect to conjunctiva cicatrization: mild, moderate, and severe. In 44 patients with inactive trachoma, conjunctival cicatrization was found, including mild (n = 15), moderate (n = 16), and severe (n = 13) cases. In patients with inactive trachoma, decreases in tear EGF (p = 0.000) concentrations and increases in tear TGF-β1 (p = 0.006) and TNF-α (p = 0.046) levels with respect to the control group were found to be concordant with conjunctival cicatrization severity. Statistically significant correlations in tear TNF-α (p = 0.018), TGF-β1 (p = 0.007), and EGF (p = 0.043) levels were found between mild and severe cicatrization groups. TNF-α and TGF-β1 have been implicated in the fibrogenic process. Elevated tear levels of inflammatory/fibrogenic cytokines may play an important role in scar formation in trachoma. It is possible that decreased tear levels of EGF, which may be important for the maintenance of corneal epithelial integrity, are related to fibrosis in the lacrimal gland ductules.

Three-Day Course of Oral Azithromycin vs Topical Oxytetracycline/Polymyxin in Treatment of Active Endemic Trachoma

PURPOSE The aim of this study on endemic trachoma was to carry out a comparison of azithromycin (3-day course, oral dose of 10 mg/kg per day) with conventional treatment (topical oxytetracycline/polymyxin ointment; twice a day for 2 months) in a rural area near Sanliurfa, Turkey. METHODS Ninety-six subjects with active trachoma were randomly assigned conventional or azithromycin treatment. Subjects were examined 1, 2, 3, and 6 months after the start of treatment. Clinical findings were recorded for each eye. Swabs were taken from upper eyelids 3 and 6 months after the start of treatment for direct fluorescein antibody test. RESULTS By six-month follow-up, trachoma had resolved clinically in 43 (89.58%) of the 48 subjects who received azithromycin, compared with 33 (68. 75%) of the 48 who were treated conventionally. Microbiological success rates (direct fluorescein antibody test negativity) were 83. 33% in the azithromycin group and 62.50% in the conventional therapy group. Compliance with both treatments was good. By 6 months, 14.58% of the subjects in azithromycin group and 33.33% of the subjects in the topical treatment group were reinfected. There were significant differences in the efficacy of the treatment effects and the re-emergence of disease between the two treatment groups. Azithromycin was well-tolerated. CONCLUSIONS These results indicate that azithromycin may be an effective alternative for patients with active trachoma. As a systemic treatment, a 3-day course oral dose has important potential for trachoma control.

Ocular involvement in cutaneous leishmaniasis four cases with blepharoconjunctivitis

Purpose: To determine the rate of ocular involvement in cutaneous leishmaniasis (CL). Methods: Nine hundred and eighty seven cutaneous leishmaniasis patients diagnosed and identified by clinical examination and parasitological methods in Harrankapi Health Centre between January 1996 and November 1997 were examined at the Harran University School of Medicine Eye Clinic, Sanliurfa, Turkey. Results: One thousand seven hundred and three CL lesions were identified in 987 patients (484 women and 503 men) with ages ranging from 0 to 78 years (mean ± SD 16.70 ± 13.47 years). A total of 33 lesions were located on the eyelid and in the periorbital region, making up 1.93% of all cutaneous lesions and 3.57% of facial lesions. In three cases with ocular involvement, blepharoconjunctivitis was identified, and in one case with ocular involvement, mechanical ptosis, lagophthalmos and blepharoconjunctivitis were identified. Conclusions: It was observed that the size of the lesions and their vicinity to the marginal free edge of the eyelid played an important role in the occurrence of ocular symptoms. It was concluded that many ocular findings could be missed because of the failure to conduct ophthalmological examination of CL cases with eyelid involvement, and hence, proper follow up and treatment may not be carried out.