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Biomedical subjects

Y Bardak

Publications and source records attributed to Y Bardak.

At least 19 recordsLinked to original sources
PubMed2005

Comparison of ICG-assisted ILM peeling and triamcinolone-assisted posterior vitreous removal in diffuse diabetic macular oedema.

AIM: To compare the effect of indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling and triamcinolone acetonide-assisted posterior vitreous removal on visual acuity in patients with diffuse diabetic macular oedema (DMO). METHODS: In total, 24 patients with diffuse DMO who underwent pars plana vitrectomy were included in this study. In all, 11 patients (mean age 57 years) were performed ICG-assisted ILM peeling; while 13 patients (mean age 54 years) underwent triamcinolone-assisted posterior vitreous removal. Patients from two different treatment regimens were compared in terms of best-corrected visual acuity (BCVA) at postoperative sixth months. RESULTS: In ICG-assisted ILM peeling group, preoperative BCVA (1.3+/-0.4, mean+/-SD, logMAR) improved postoperatively to 0.9+/-0.5 (P=0.011). In eyes underwent triamcinolone-assisted posterior vitreous removal, baseline BCVA of 1.4+/-0.4 improved to 1.0+/-0.5 (P=0.007). There was no difference between baseline as well as postoperative sixth-month BCVA results of both groups (P=0.59 and P=0.57, respectively). CONCLUSIONS: Triamcinolone-assisted posterior vitreous removal and ICG-assisted ILM peeling have the same effect in terms of postoperative BCVA in patients with diffuse DMO.

Diabetes Mellitus, Type 2↗
PubMed2001

Vitreoretinal surgery in Behçet's disease with severe ocular complications.

PURPOSE: To investigate effects of vitreoretinal surgery in Behçet's disease. MATERIALS AND METHOD: Vitreoretinal surgery was applied to 26 eyes of 21 patients with Behçet's disease. Preoperative and postoperative visual acuities, number and duration of attacks, anterior and posterior segment pathologies were evaluated. RESULTS: The mean age of the patients was 33 years and female/male ratio was 6/15. The mean follow-up was 23 months. Visual acuity increased in 15 eyes (58%), did not change in 11 eyes (42%). In the postoperative period, there was a significant decrease in mean number of uveitis attacks compared to the preoperative period (p=0.001), as well as a significant decrease in the mean duration of uveitis attacks (p=0.001). In the postoperative follow-up, intravitreal haemorrhage in 2 eyes (8%), posterior subcapsular cataract in 5 eyes (19%) and corticonuclear cataract in 2 eyes (8%) were observed. Posterior capsular opacification (PCO) developed in 5 of 16 eyes (31%) having ECLE-IOL. CME continued in 3 eyes (12%). CONCLUSION: Vitreoretinal surgery has favourable effect on the visual and anatomic prognosis in Behçet's patients with severe ocular complications.

Adolescent↗
PubMed2000

Closed chamber iridodialysis repair using a needle with a distal hole.

We describe a closed-system technique of iridodialysis repair using a 22.0 mm, plastic handled, 27 gauge straight needle with a hole 1.0 mm proximal to the tip. The distal hole is suitable for passage of 9-0 or 10-0 mm polypropylene or nylon sutures. The technique was effective in 8 patients with traumatic iridodialysis in the upper and inferior temporal quadrants.

Adolescent↗
PubMed2000

Effect of melatonin against oxidative stress in ultraviolet-B exposed rat lens.

PURPOSE: To investigate the defensive effect of melatonin against oxidative stresses in ultraviolet-B (UVB) radiation induced cataract development. METHODS: Young rats received 8 kJ/m(2) UVB for 15 min. For the intervention of cataract development intraperitoneal injection of melatonin (4 mg/kg daily for 1 week) following UVB exposure was performed. Lenticular glutathione peroxidase (GSHPx), catalase (CAT), superoxide dismutase (SOD) activities and glutathione (GSH), malondialdehyde (MDA) levels were determined in UVB-melatonin, UVB, and control groups. RESULTS: One week after exposure in the UVB group, lens opacities were observed and CAT, SOD, and GSHPx activities, and GSH level were lower than control and MDA level was higher than control (p < 0.05). In the UVB-melatonin group CAT and SOD activities were lower than control (p < 0.05), and the MDA level was lower than the UVB group (p < 0.05). CONCLUSIONS: These results suggest that melatonin may protect against the UVB-induced cataract development by directly quenching lipid peroxides and indirectly by enhancing the production of the endogenous antioxidant GSH.

Animals↗
PubMed1999

Nickel, chromium, manganese, iron and aluminum levels in human cataractous and normal lenses.

Atomic absorption spectrophotometry was used to detect lenticular nickel, chromium, manganese, iron and aluminum levels in 37 senile cataractous and 9 normal human lenses. The nuclear parts of the lenses were used for the study in both groups. It was found that the concentrations of nickel and iron were significantly higher, and those of chromium, manganese and aluminum were significantly lower in human cataractous lenses than those in normal human lenses. None of the elements showed a significant difference according to sex in both groups. As remarkable differences in chromium, manganese, iron, aluminum and nickel levels exist in cataractous lenses, all the five elements may play some roles in cataractogenesis.

Aged↗
PubMed1999

Superoxide dismutase, catalase, glutathione peroxidase and xanthine oxidase in diabetic rat lenses.

The activities of the protective enzymes, superoxide dismutase, catalase, glutathione peroxidase and of xanthine oxidase, an enzyme acting as a source of O(-)(2), were measured in the lenses of alloxan-induced diabetic and control rats. Superoxide dismutase and glutathione peroxidase activities were found to be significantly decreased, while catalase and xanthine oxidase activities were increased. This means that the ratio of the oxidant/antioxidant enzymes increases in the diabetic rat lens, suggesting an increased oxidative stress. This imbalance is possibly an important contributing factor in the pathogenesis of diabetic cataract.

Animals↗
PubMed1999

An unusual complication of retinal reattachment surgery.

The authors report a case with an unusual late extraocular complication of scleral buckling and local silicone sponge implant. Four years after the reattachment surgery, a ptotic upper eyelid perforated by local silicone sponge implant and fistula between upper eyelid and sclera were detected. Primary repair of upper eyelid and removal of silicone sponge were performed. One year later, the retina was attached and there was no problem with the upper eyelid. Cryotherapy, episcleral explant (scleral buckling), and local implant (sponge) are frequently used and effective methods for retinal reattachment surgery. Postoperative early and late complications have been reported. To our knowledge, there is no report of upper eyelid perforation, ptosis and fistula formation caused by silicone sponge implant rejection.

Eye Injuries↗
PubMed1998

Effect of verapamil on lenticular calcium, magnesium and iron in radiation exposed rats.

PURPOSE: To investigate the effect of verapamil on lenticular calcium, magnesium, iron and on radiation-induced cataract in rats. METHODS: Thirty-seven, female, Wistar Albino rats, weighing 180-230 g were randomly grouped as follows: control group (10 rats), radiation group (13 rats) and radiation-verapamil group (14 rats). Both radiation and radiation-verapamil groups received 5 Gy radiation to the whole body in a single dose, including both eyes within the irradiation volume; in addition the verapamil group received daily subcutaneous injections of 8 mg/kg verapamil starting on the first day of radiation. At the end of an 8-week experimental period, the animals were killed by decapitation. Lenticular calcium, magnesium, and iron levels were studied. RESULTS: The mean lens calcium level for the radiation group was significantly higher than that for the control and radiation-verapamil groups and, there was no significant difference between the control and radiation-verapamil groups. The mean lens magnesium value for the radiation group was significantly higher than that for the control group. In the radiation-verapamil group the mean lens magnesium content was significantly lower than that for the radiation group. The iron level in the radiation group was significantly higher than that for the radiation-verapamil group. CONCLUSIONS: The lens calcium, magnesium and iron contents increased after radiation exposure. Verapamil treatment significantly reduced the increase in the lenticular content of calcium, magnesium and iron, indicating a probable protective effect of verapamil in radiation-induced cataract formation.

Animals↗
PubMed1998

Lenticular calcium, magnesium, and iron levels in diabetic rats and verapamil effect.

Lenticular calcium (Ca), magnesium (Mg), and iron (Fe) changes in diabetic rats and the effects of the Ca antagonist drug verapamil on this electrolyte imbalance were studied. Verapamil administration had no effect on the blood glucose values. Compared to the control group, a significant increase was observed in the lenticular Ca, Mg, and Fe content of the diabetic rats. Eight weeks of verapamil administration to the diabetic animals significantly reduced lenticular Ca, Mg, Fe values. Therefore it is suggested that verapamil might be a useful drug to prevent diabetic cataract formation.

Animals↗
PubMedDate not supplied

Ocular hypotony after laser suture lysis following trabeculectomy with mitomycin C.

BACKGROUND: To report our experience with laser suture lysis (LSL) following trabeculectomy with mitomycin C, its timing, effectiveness and related complications. METHODS: We retrospectively examined 38 consecutive eyes of 36 patients that underwent LSL following trabeculectomy with mitomycin C. RESULTS: The mean preLSL intraocular pressure (IOP) was 27.0 mm Hg (SD 6.3, range 16-39 mm Hg) and the postLSL IOP (IOP 1 h after the last session of LSL) was 16.0 mm Hg (SD 7.2, range 3-31 mm Hg). Following the LSL in 7 eyes (7 of 38) hypotony (IOP<6 mm Hg, lasting more than 24 h) developed. Two groups were defined. In group I no hypotony was found after LSL and group II went through a period of hypotony. The time interval between surgery and LSL was significantly shorter in group II (mean 5.7, SD 7.5, range 1-19 days), compared to group I ( mean 14.7, SD 13.0, range 1-44 days) (p=0.041). The mean final IOP (IOP measured at the last visit) was 13.3 mm Hg (SD 3.4, range 6-20 mm Hg) and mean follow-up was 6.1 months (SD 3.9, range 2.0-15.2 months). No hypotony was found at final examination. PostLSL IOP and final IOP were significantly lower in group II (p=0.002 and p=0.024 respectively). IOP reduction by LSL was significantly greater in group II (p=0.046). CONCLUSION: LSL is an effective and safe procedure to lower the IOP following trabeculectomy with mitomycin C. Early application of LSL results in lower final IOPs, but has a higher risk of hypotony.

Adolescent↗
PubMedDate not supplied

Effect of melatonin on lenticular calcium and magnesium in rats exposed to ultraviolet radiation.

Six-week-old rats received 8 kJ/m(2) ultraviolet B (UVB) for 15 min. For the intervention in cataract development, intraperitoneal injection of melatonin (4 mg/kg daily for 1 week) following UVB exposure was performed. Lenticular calcium and magnesium levels were determined in UVB + melatonin, UVB and control groups. One week after exposure, significantly more cataractous changes were observed in the UVB group than the UVB + melatonin group. The mean lens calcium and magnesium levels for the UVB group were significantly higher than those for the control and the UVB + melatonin groups. There were no significant differences between the control and the UVB + melatonin groups for the mean lens calcium and magnesium levels.

Animals↗
PubMedDate not supplied

Nucleoside diphosphate kinase (nm23 protein) expression in retinoblastoma.

Forty-two enucleated eyes of 42 patients with unilateral retinoblastoma were studied histologically, including histochemically examination with anti-nm23 polyclonal antibody which does not recognise cDNA but its product. Primary tumours of >15 mm diameter with less evidence of apoptosis and with the most pleomorphic and anaplastic nuclei were associated with an increased risk of distant metastasis, but rosette formation did not discriminate. A high intensity of nm23 staining also indicated a tendency to metastasize, consistent with childhood neuroblastoma but in contrast to findings in carcinoma of the breast, colon and uterine cervix.

Antigens, Neoplasm↗
PubMedDate not supplied

nm23 Expression in choroidal melanoma.

nm23 protein expression of choroidal melanoma was investigated to determine its relationship with clinical and histopathological characteristics of the tumour. Thirty-four consecutive choroidal melanoma patients were examined by immunohistochemistry. Although age, sex, tumour cell type, tumour size, pigmentation, necrosis, apoptosis and tumour lymphocytic infiltration were not correlated with nm23 protein expression, tumours with low percentages of nm23-positive cells revealed higher nuclear grades and predominant mitotic figures. nm23 may be associated with melanoma progression, but there is no proof that it plays a role in the metabolic process of the tumour.

Adult↗
PubMedDate not supplied

Treatment of hyperopia with contact Ho:YAG laser thermal keratoplasty.

PURPOSE: To evaluate the effectiveness, safety, and stability of contact Ho:YAG laser thermal keratoplasty for low to moderate hyperopia. METHODS: Fifty-five hyperopic eyes of 39 patients were treated with a Technomed contact Ho:YAG laser; 23 eyes were treated a second time. Treatment parameters were 1 octagonal ring of 8 spots with a treatment diameter of 6 mm, 7 mm, or 8 mm. Efficacy of the Ho:YAG laser treatment was evaluated after 6 months, comparing 3 treatment zone diameters. Stability and efficacy after 12 months was evaluated comparing 7-mm and 8-mm treatment zone diameters. RESULTS: Mean reduction of spherical equivalent refraction after 6 months was not statistically significantly different between the 6-mm or 7-mm diameter zones: 1.42 (+/- 1.30) D versus 2.22 (+/- 0.44) D. An 8-mm diameter treatment zone was significantly less effective, 1.12 (+/- 0.47) D. Longer follow-up did not show stability: mean reduction of spherical equivalent manifest refraction was 1.58 (+/- 0.45) D for the 7-mm diameter treatment zone and 0.82 (+/- 0.61) D for the 8-mm diameter treatment zone after approximately 12 months. Retreatment had a limited additive effect. No clinically significant loss of spectacle-corrected visual acuity was reported. No eyes lost more than 1 line of visual acuity. CONCLUSION: Contact Ho:YAG laser thermal keratoplasty corrected hyperopia up to 2.50 D, but predictability was poor and a regression of initial effect occurred. Instability of refraction persisted to 1 year after surgery.

Adult↗