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Biomedical subjects

O Cekiç

Publications and source records attributed to O Cekiç.

At least 37 records · Page 2Linked to original sources
PubMed1999

Human aqueous and vitreous humour levels of ciprofloxacin following oral and topical administration.

PURPOSE: To assess aqueous and vitreous humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. METHODS: In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and vitreous humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. RESULTS: The aqueous and vitreous humour levels of ciprofloxacin were 0.59 +/- 0.06 microgram/ml (mean +/- SEM) and 0.64 +/- 0.06 microgram/ml after oral and 0.44 +/- 0.07 microgram/ml and 0.22 +/- 0.04 microgram/ml after topical ciprofloxacin administration, respectively. Aqueous humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the vitreous level of the drug after oral administration was significantly higher than that after topical administration (p < 0.001). CONCLUSION: Ocular bioavailability of ciprofloxacin in aqueous humour following oral and topical administration is found to be similar when the drug was applied as described above. Penetration of ciprofloxacin into vitreous humour is less than that into aqueous humour after topical administration.

Administration, Oral↗
PubMed1999

Aqueous humour levels of topically applied ciprofloxacin and ofloxacin in the same subjects.

PURPOSE: To evaluate aqueous humour levels of topical 0.3% ciprofloxacin and 0.3% ofloxacin in the same subjects. METHODS: Thirty-two bilateral cataractous patients received topical 0.3% ciprofloxacin in one eye and 0.3% ofloxacin in the other eye before each cataract extraction. Eyedrops were repetitively instilled for 6 h. Aqueous humour samples were collected and assayed for drug concentrations by a method described originally by us using high-performance liquid chromatography. RESULTS: Mean aqueous ciprofloxacin and ofloxacin levels were 0.33 +/- 0.04 microgram/ml (mean +/- SEM) and 1.34 +/- 0.14 micrograms/ml respectively (p < 0.0001). CONCLUSION: Ofloxacin level in the aqueous humour is 4 times higher than that of ciprofloxacin in the same subjects.

Administration, Topical↗
PubMed1999

Effect of intracameral carbachol on intraocular pressure following clear corneal phacoemulsification.

PURPOSE: To investigate the effect of 0.01% carbachol on early intraocular pressure (IOP) after cataract extraction with phacoemulsification. METHODS: Fifty-one patients who underwent cataract extraction with phacoemulsification and intraocular lens implantation were prospectively randomly assigned to one of two groups. Twenty-seven patients were given 0.5 ml carbachol intracamerally (carbachol group); the other 24 patients were given the same amount of balanced salt solution intracamerally (control group). IOPs were measured by Goldmann applantation tonometry on the day before surgery, and at 8 h, 24 h and 7 days post-operatively. RESULTS: There was no difference between the mean IOPs of the groups pre-operatively (p > 0.5). All the mean post-operative IOP values of the carbachol group were lower than those of the control group. At 8 and 24 h post-operatively the mean IOP was 12.4 +/- 3.4 mmHg and 13.1 +/- 4.5 mmHg respectively in the carbachol group, 19.4 +/- 6.4 mmHg and 17.2 +/- 4.2 mmHg respectively in the control group. The differences were significant (p < 0.04 and p < 0.05). There was no significant difference between the values at 7 days post-operatively (p > 0.8). An IOP greater than 25 mmHg was recorded at 8 h and 24 h post-operatively in 8 (33%) and 4 (17%) of the control group and in 1 (4%) and 1 (4%) of the carbachol group. All the IOPs were 20 mmHg or lower in both groups at 7 days post-operatively. CONCLUSION: Patients treated with intracameral carbachol following uncomplicated clear corneal phacoemulsification and posterior chamber intraocular lens implantation demonstrate lower early post-operative IOP.

Carbachol↗
PubMed1999

Vitrectomy with silicone oil or long-acting gas in eyes with giant retinal tears: long-term follow-up of a randomized clinical trial.

PURPOSE: To determine if either silicone oil or perfluoropropane (C3F8) gas is superior to the other in the treatment of giant retinal tears complicated by proliferative vitreoretinopathy. METHODS: Forty-seven eyes with giant retinal tears were treated in a prospective randomized fashion. Twenty-two eyes were randomized to C3F8 gas and 25 eyes were randomized to silicone oil. Follow-up of 60 months is reported. Of the silicone oil-treated eyes, 9 had oil retained in the eye; oil was removed from the remaining 16 eyes. Successful anatomic attachment of the retina, final visual acuity, and surgical complications were the main outcome measures. RESULTS: There were no differences between the groups in any of the main outcome measures. CONCLUSIONS: This study showed that silicone oil and C3F8 gas are equal in most respects for the management of giant retinal tears with proliferative vitreoretinopathy.

Adolescent↗
PubMed1999

Penetration of topical, oral, and combined administered ofloxacin into the subretinal fluid.

AIMS: To assess the subretinal fluid (SRF) levels of ofloxacin following topical, oral or combined administration. METHODS: 31 patients undergoing conventional retinal reattachment surgery were randomly assigned to three groups. Nine patients received topical ofloxacin, 11 patients received oral ofloxacin, and the other 11 patients received combined administration. Collected SRF samples were analysed for drug level by using high performance liquid chromatography. RESULTS: SRF drug levels after oral and combined administration were significantly higher than that after topical administration (p=0.0002 and p=0.0002, respectively) while there was no significant difference between oral and combined administration (p=0.0844). CONCLUSIONS: Ocular bioavailability of ofloxacin in SRF after oral and combined administration is equivalent. The addition of oral ofloxacin to topical therapy increased drug SRF penetration sixfold.

Administration, Oral↗
PubMed1999

Does convergence, not accommodation, cause axial-length elongation at near? A biometric study in teens.

To determine whether convergence rather than accommodation has a primary effect on the changes in axial length and other biometric components during near fixation, we measured the anterior chamber depth, lens thickness, vitreous length and axial length in the right eyes of 124 young male subjects while their left eyes focused at distance (6 m) and near (20 cm). The measurements were performed before and after cycloplegia in the right eye, so we aimed to study biometric components of the eye in the states of accommodation and nonaccommodation, but converging at near. While the left eye focused at near, the axial length increased significantly with and without cycloplegia (p < 0.0005 and p < 0.0005). The vitreous length was the main increasing ocular biometric component at near both with and without cycloplegia (p < 0.044 and p = 0.001, respectively). At near, there was no difference between two mean axial length and two vitreous length measurements both with and without cycloplegia (p = 0.672 and p = 0.595, respectively). Under cycloplegia, anterior chamber depth also increased significantly at near fixation (p = 0. 012). Axial elongation at near fixation, mainly due to an increase in vitreous length, may result from the effect of accommodative convergence rather than accommodation itself. Much use of convergence, not accommodation, may be one of the contributing factors in adult onset and adult progression of myopia.

Accommodation, Ocular↗
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

Topically applied water extract of propolis to suppress corneal neovascularization in rabbits.

PURPOSE: Propolis, a natural honey bee hive product, has anti-inflammatory and antioxidative properties. We aimed to assess the possible contribution of topically applied propolis to the suppression of corneal neovascularization (CNV). METHODS: The effect of a water extract of propolis (WEP) 1% drops (group 1) in comparison with dexamethasone 0.1% (group 2) and saline (group 3) on CNV was tested in rabbit corneas injured by silver nitrate cauterization. The extent of CNV was quantitated as the area of CNV and the percent area of CNV for each cornea of the three groups (12 right eyes per group) in the first week of the treatment. The mean percent CNV was used for statistical analysis. RESULTS: The corneas treated with the topical WEP 1% had an almost equal percent CNV as compared with the corneas treated with topical dexamethasone 0.1% and had less percent CNV than the control eyes. The quantitative analysis in groups 1, 2 and 3 revealed that the mean percent CNV was 41.0 +/- 14.1, 39.4 +/- 11.0 and 56.9 +/- 18.4, respectively. The differences between both groups 1 and 3 as well as groups 2 and 3 were statistically significant (p = 0.02 and p = 0.01, respectively), whereas the difference between groups 1 and 2 was not significant (p = 0.86). CONCLUSIONS: The topical application of a WEP 1% has an inhibitory effect on CNV in the rabbit's cornea. The inhibitory effect of propolis was shown to be comparable to that of topical dexamethasone 0.1%, a potent inhibitor of angiogenesis. We suggest that the effect of propolis may partially be due to its inhibitory effect on the activity of both cyclo-oxygenase and lipo-oxygenase.

Administration, Topical↗
PubMed1999

The relationship between capsulorhexis size and anterior chamber depth relation.

BACKGROUND AND OBJECTIVE: To determine whether the diameter of the capsulorhexis has an effect on anterior chamber depth (ACD) following phacoemulsification surgery. PATIENTS AND METHODS: Fifty-one consecutive patients were selected for cataract extraction by phacoemulsification with intraocular lens (IOL) implantation. Twenty-two of 51 patients underwent 4 mm capsulorhexis, while the rest underwent 6 mm. All were implanted with a multi-piece polymethyl methacrylate posterior chamber IOL with 5.0 mm diameter biconvex optic and flexible haptic. They were followed 3 months postoperatively. The width of the capsulorhexis was assured according to the IOL optic implanted intraoperatively, and by the help of slit-lamp measurement after dilatation of the pupil on the first postoperative day. ACD and axial length (AL) of patients was obtained by ultrasonography on both the days before surgery, and the first and seventh postoperative days, and after 30, 60 and 90 days. RESULTS: Early significant increase of ACD and ACD/AL ratios were observed in only the 6 mm capsulorhexis group on the first day postoperatively (P = .012, and P = .018). On the 90th postoperative day, ACD increased significantly both in the 4 mm (P = .002) and the 6 mm capsulorhexis groups (P = .049) when compared to preoperative values. For the same period, meaningful increase in ACD/AL ratio in the eyes with both 4 mm and 6 mm capsulorhexis groups was also noted compared with preoperatively (P = .002 and P = .019). There was a statistical difference between the 90th day ACD values of 4 mm (3.73 +/- 0.32 mm, mean +/- standard deviation) and 6 mm capsulorhexis groups (3.50 +/- 0.33 mm) (P = .028). For the same period, ACD/AL ratio was also significantly different for both groups (0.152 +/- 0.01, and 0.142 +/- 0.01 respectively) (P = .004). The refractive error changes followed the ACD changes and showed meaningful differences between 1st and 90th days postoperative values of each group (P = .029, and P = .014, respectively). CONCLUSION: A 4 mm capsulorhexis results in a longer postoperative ACD than does a 6 mm capsulorhexis for the IOL type used in this study.

Adult↗
PubMed1999

Penetration of ofloxacin and ciprofloxacin in aqueous humor after topical administration.

BACKGROUND AND OBJECTIVE: To compare the aqueous humor levels of 0.3% ofloxacin and 0.3% ciprofloxacin containing eyedrops in patients with healthy cornea. PATIENTS AND METHODS: Fifty patients with cataract were randomly assigned to have 0.3% ofloxacin containing eyedrop (25 patients) or 0.3% ciprofloxacin containing eyedrop (25 patients). Both drugs were repetitively instilled to each patient for 6 hours before the surgery. Aqueous samples were collected after penetrating the anterior chamber during cataract extraction and assayed by high-performance liquid chromatography method. RESULTS: The aqueous humor level of ofloxacin (1.43 +/- 0.26 microg/ml, mean +/- SEM) was significantly higher than that of ciprofloxacin (0.35 +/- 0.07 microg/ml) following the topical application (P < .0002). CONCLUSION: Aqueous humor penetration of topical ofloxacin is about 4 times higher than that of topical ciprofloxacin when the drugs are applied as described above.

Administration, Topical↗
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

Comparison of the results of primary and secondary implantation of flexible open-loop anterior chamber intraocular lens.

PURPOSE: To assess and compare the results of primary and secondary implantation of flexible open-loop anterior chamber intraocular lenses (AC-IOLs). METHODS: A series of 57 eyes of 56 patients with flexible AC-IOLs were reviewed in two groups. In group I (n = 35) an AC-IOL was implanted primarily, because of posterior capsule problems during extracapsular cataract extraction (ECCE), and in group II (n = 22) secondarily after intracapsular cataract extraction (ICCE). Follow-up was from 12 to 38 months. RESULTS: Mean post-operative best-corrected visual acuity in group I was significantly lower (20/37.38) than that of group II (20/29.20) (p = 0.044). Best corrected visual acuity of 20/40 or better was achieved in 19 of 29 eyes (65%) in group I, and in 16 of 21 eyes (76%) in group II. The difference was not statistically significant (p > 0.05). In group II 18 eyes (86%) maintained or improved visual acuity. In group I, 17 eyes (49%) had a total of 22 complications, while 7 eyes (32%) had 9 complications in group II (p > 0.05). CONCLUSIONS: Flexible open-loop AC-IOLs are suitable for both primary and secondary implantation to correct aphakia. Secondary implantation of flexible open-loop AC-IOLs after ICCE seems to have a more favourable visual outcome and a lower complication rate than primary implantation in complicated ECCE cases.

Adolescent↗
PubMed1998

Comparison of aqueous humour and vitreous humour levels of two 0.3% ciprofloxacin eyedrops.

BACKGROUND: Two ophthalmic solutions of 0.3% ciprofloxacin eyedrops are available in Turkey: Ciloxan and Siprogut. The objective of this study was to compare the concentrations of drug produced by the two products in the aqueous humour and vitreous humour after local administration. METHODS: Twenty-one patients undergoing primary vitreoretinal surgery received either Ciloxan (10 patients) or Siprogut (11 patients). Six hours before surgery, two drops of solution were instilled onto the operative eye. Drops were then instilled every 30 minutes for the first 3 hours and then hourly for the next 3 hours. Aqueous and vitreous samples were collected 30 minutes after administration of the last dose and were assayed for ciprofloxacin concentration by means of high-performance liquid chromatography with fluorometric detection. RESULTS: The mean aqueous humour concentrations of Ciloxan and Siprogut were 0.36 (standard error of the mean [SEM] 0.09) microgram/mL and 0.44 (SEM 0.17) microgram/mL respectively. The corresponding vitreous humour concentrations were 0.21 (SEM 0.05) microgram/mL and 0.22 (SEM 0.06) microgram/mL. Neither of these differences was statistically significant. The aqueous and vitreous levels of both products exceeded the minimum inhibitory concentrations for certain bacterial species that frequently cause intraocular infections. INTERPRETATION: Our results show that the ocular bioavailability of Ciloxan and Siprogut after local administration is equivalent. Penetration of ciprofloxacin into the vitreous humour seems to be poorer than that into the aqueous humour.

Adult↗