Intravitreal erythropoietin injection in late-stage optic neuropathy: a safety study on human.

AIM: To evaluate the whether intravitreal erythropoietin (EPO) administration has any beneficial or adverse effect in patients with late-stage optic neuropathy (ON) or not. METHODS: The study examined 16 eyes of 16 patients who had late-stage ON and ≥1/20 best-corrected visual acuity (BCVA) in their affected eye. There were nonarteritic ischemic ON in 10 (62.5%) eyes, traumatic ON in 4 (25.0%) eyes and methanol-induced ON in 2 (12.5%) eyes. Using pars plana approach, 2000 IU/0.2 ml EPO was administered intravitreally with a 30-gauge needle. Injections were administered three times with 6-week intervals. We compared the differences in the BCVA, intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, pattern visual evoked potentials (p-VEP) and pattern electroretinography (p-ERG) parameters performed at initial examination and final visits. RESULTS: The mean age of the patients was 52.38 ± 12.00 years; 2 (12.50%) of them were female, and 14 (87.50%) of them were male. The mean BCVA levels of 16 patients with optic atrophy were 1.12 ± 0.25 logMAR at the initial examination and 1.08 ± 0.26 logMAR at the final visit (p = 0.102). There was no statistically significant difference between the initial and final RNFL thicknesses, IOP values, p-ERG or p-VEP responses. CONCLUSIONS: Intravitreal EPO injections have no beneficial or detrimental effect on the late stage of ON. Further studies are necessary to compare our results in patients with ON in earlier stages.

CHOROIDAL THICKNESS IN PATIENTS WITH STARGARDT DISEASE.

PURPOSE: To investigate the relationship between choroidal thicknesses (CT), central foveal thicknesses, multifocal electroretinography (mf-ERG) responses, and best-corrected visual acuity levels in patients with Stargardt disease (STGD). METHODS: A total of 30 eyes of 30 patients with STGD, and 30 age- and sex-matched healthy controls were included in the study. All participants underwent detailed ophthalmic examination including best-corrected visual acuity and spectral domain optical coherence tomography measurements, and also patients with STGD were performed mf-ERG. RESULTS: The mean subfoveal CT values were 271.95 ± 85.57 µm in patients with STGD and 355.73 ± 87.41 µm in the control group (P < 0.001). The mean central foveal thickness values were 223.56 ± 61.38 µm in patients with STGD and 272.46 ± 27.52 µm in the control group (P < 0.001). The mean central and paracentral mf-ERG responses (45.71 ± 26.60 and 16.47 ± 10.75 Nv/deg respectively) in patients with STGD were significantly lower from the normal ranges (66.6-130.8 Nv/deg and 30.9-77.7 Nv/deg, respectively; P < 0.001 for both). There was a statistically significant correlation between subfoveal CT and best-corrected visual acuity levels (P = 0.012, r = -0.452), and between parafoveal CT and inner retinal thickness and paracentral mf-ERG responses (P = 0.043, r = +0.372 and P = 0.049, r = +0.363, respectively). Paracentral mf-ERG responses were also correlated with outer retinal thickness values (P = 0.005, r = +0.503). CONCLUSION: Patients with STGD have a thinner CT, which may be responsible for some of the clinical findings. The pathophysiological significance of these findings needs further study.

Serum Levels of Omentin in Pseudoexfoliation Syndrome.

PURPOSE: Omentin, a member of the adipocytokines family, is derived from adipose tissue and a lower level of serum omentin is considered as a metabolic risk factor. The aim of the present study is to evaluate the serum levels of omentin in patients with pseudoexfoliation syndrome (PES). MATERIALS AND METHODS: Patients without any systemic or ocular disease other than PES were included in the study. Age-matched and sex-matched healthy volunteers without PES were accepted as a control group. After detailed ophthalmologic examination, blood samples were obtained from a forearm vein. Serum levels of omentin were determined by the method of enzyme-linked immunosorbent assay. RESULTS: The mean age of the PES group (12 females, 12 males, n=24) was 75.2 ± 8.4 years, and the control group (10 females, 10 males, n=20) was 75 ± 6.7 years. There was no difference between the groups in terms of age (P=0.93) and sex (P=0.9). The mean serum levels of omentin in the PES group were 801.5 ± 317.1 ng/mL and in the control group were 1150.1 ± 584.1 ng/mL. The mean serum omentin levels were significantly lower in patients with PES (P=0.016). CONCLUSION: Lower levels of serum omentin in patients with PES compared with healthy subjects may support the theory of systemic nature of the disease.

Tear and serum vitamin D levels in children with allergic rhinoconjunctivitis

BACKGROUND: Although solid cohort studies confirmed a preventative role for the anti-oxidant vitamin D in allergic asthma, a limited number of studies focused on allergic rhinoconjunctivitis (ARC). Here, we aimed to determine 25-hydroxycholecalciferol levels in tear and serum in young allergic rhinoconjunctivitis patients as compared to their apparently healthy matched controls. METHODS: In total, 22 children with allergic rhinoconjunctivitis and 31 healthy control subjects underwent serum total IgE and 25-hydroxycholecalciferol measurements. Tear levels of 25-hydroxycholecalciferol were also determined in both groups. RESULTS: The mean serum total IgE level in the ARC group (143.6 ± 132.8 IU/ml) was significantly higher than that in the control group (54.8 ± 44.1 IU/ml; p = 0.03). Serum 25(OH)D levels were significantly higher in the ARC group (34.1 ± 12.7 ng/ml) than in the healthy controls (21.8 ± 11.3 ng/ml; p = 0.001). CONCLUSIONS: To our knowledge, this is the first reported study to show an association between serum 25-hydroxycholecalciferol and ARC in a childhood group. Higher levels of serum 25-hydroxycholecalciferol in children with allergic rhinoconjunctivitis may indicate a possible aetiopathogenic mechanism in the development of allergic rhinoconjunctivitis. This is also the first report to examine tear fluid vitamin D levels in paediatric ARC patient

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Contact lens impact on quality of life in keratoconus patients: rigid gas permeable versus soft silicone-hydrogel keratoconus lenses.

AIM: To determine the impact of rigid gas permeable (RGP) and silicone-hydrogel keratoconus lenses on the quality of life (QoL) in keratoconus (KCN) patients using the self-reported results from the Contact Lens Impact on Quality of Life (CLIQ) Questionnaire. METHODS: From January 2013 to April 2013, 27 consecutive KCN patients who wore RGP contact lenses (conflexair100 UV KE Zeiss-Wöhlk) or soft silicone-hydrogel contact lenses (SHCLs) for KCN (KeraSoft IC- Bausch&Lomb or Hydrocone Toris K-Swiss lens) completed the CLIQ questionnaire. RESULTS: The mean age of 27 patients was 29.6±8.0y. Fifteen patients were RGP user. The groups were comparable with respect to the mean patient age, sex, and mean K values (P=0.1, P=0.8 and P=0.1, respectively). The mean CLIQperson measure was 42.8±5.5 in RGP group and 39.6±5.5 in SHCLs for KCN group (P=0.06). CLIQperson measure was positively correlated with steep K value (r=0.301, P=0.04). When eyes were stratified by visual acuity with contact lenses, the mean CLIQperson measure was 42.01±5.6 in eyes with a visual acuity of 20/20-20/25 (n=44) and 38.4±5.26 in eyes with a visual acuity of 20/32 or less (n=10; P=0.097). CONCLUSION: RGP lenses and SHCLs for KCN have similar impact on QoL.

Endothelin-1 and Nitric Oxide Levels in Exudative Age-Related Macular Degeneration.

PURPOSE: To evaluate plasma levels of endothelin-1 (ET-1) and nitric oxide (NO) in patients with exudative age-related macular degeneration (AMD). METHODS: In this study, ET-1 levels, as well as nitrite plus nitrate concentrations as an indicator of plasma NO level, were measured in the plasma of 20 subjects with exudative AMD and compared with 20 healthy age and sex matched controls. RESULTS: Mean plasma ET-1 level was significantly higher in exudative AMD patients as compared to control subjects (0.35 ± 0.06 fmol/ml versus 0.17 ± 0.03 fmol/ml, P = 0.015). Patients with exudative AMD also showed significantly lower mean plasma levels of nitrite plus nitrate as compared to the controls (58.9 ± 2.7 µmol/l versus 82.6 ± 5.9 µmol/l, P = 0.001). CONCLUSION: Increased concentrations of ET-1 and reduced levels of NO in the plasma may suggest an imbalance between vasoconstrictor and vasodilator agents, respectively, as a reflection of endothelial dysfunction in the pathogenesis of AMD. These findings may also imply the role of vasoconstriction in exudative AMD.

Serum Uric Acid, Alanine Aminotransferase, Hemoglobin and Red Blood Cell Count Levels in Pseudoexfoliation Syndrome.

Purpose. The pathogenesis of pseudoexfoliation (PEX), the most common cause of secondary glaucoma, has not been clearly identified, but there is increasing evidence that points out the role of oxidative stress. The aim of this study is to evaluate some of the most commonly used blood parameters, hemoglobin (Hb), red blood cell count (RBC), alanine aminotransferase (ALT), and uric acid (UA) levels, in subjects with PEX. Materials and Methods. This study is performed in a state hospital between November 2011 and December 2012. Retrospective chart review of subjects who underwent cataract surgery was performed. Thirty-one healthy subjects with PEX and 34 healthy subjects without PEX were evaluated. Hb, RBC, ALT, and UA levels were recorded. Student's t-test was used to compare the two groups. Results. The mean age was 73.6 ± 14.1 years in PEX group and 70.1 ± 12.7 in control group (p = 0.293). Hb, RBC, ALT, and UA levels did not show a statistically significant difference among PEX and control groups (p > 0.05 for all). Conclusion. Serum levels of Hb, RBC, ALT, and UA levels were similar in subjects with and without PEX. Further studies are needed to clarify the precise role of Hb, RBC, ALT, and UA in the pathogenesis of PEX.

Serum and aqueous xanthine oxidase levels, and mRNA expression in anterior lens epithelial cells in pseudoexfoliation.

PURPOSE: The aim of this study was to determine serum and aqueous xanthine oxidase (XO) levels, and mRNA expression in anterior lens epithelial cells in pseudoexfoliation (PEX). METHODS: In this prospective study, serum, aqueous and anterior lens capsules were taken from 21 patients with PEX and 23 normal subjects who had undergone routine cataract surgery. Serum and aqueous XO levels were analyzed using the colorimetric method. mRNA expression of XO in anterior lens epithelial cells was evaluated using reverse transcription polymerase chain reaction analysis. RESULTS: Serum XO levels (means ± standard deviations) were 207.0 ± 86.1 IU/mL and 240.6 ± 114.1 IU/mL in the normal and PEX groups, respectively (p = 0.310). Aqueous XO levels (means ± standard deviations) were 65.5 ± 54.3 IU/mL in the normal group and 130.5 ± 117.4 IU/mL in the PEX group (p = 0.028). There was a 2.9 fold decrease in mRNA expression in anterior lens epithelial cells of PEX, which is significantly lower than the normal group (p = 0.01). CONCLUSIONS: Higher aqueous XO levels lacking associated different serum XO suggests higher oxidative stress in the aqueous. Higher aqueous XO levels in PEX with decreased mRNA expression in anterior lens epithelial cells indicate possible overexpression of XO in other structures related to the aqueous.

The intraocular pressure and central corneal thickness in healthy premature infants.

PURPOSE: To describe the normal values of intraocular pressure (IOP) and central corneal thickness (CCT) in healthy premature infants. METHODS: Infants of <32 weeks' gestational age who underwent screened for retinopathy of prematurity were prospectively enrolled. The same ophthalmologist measured IOP by applanation tonometry and CCT using ultrasonic pachymetry. Infants were divided into four groups according to postconceptional ages (PCA). The mean values of the IOP and CCT were compared by nonparametric statistical tests, and the relationship of the PCA with IOP and CCT were analyzed with correlation tests. Only right eye measurements were analyzed. RESULTS: A total of 470 infants (mean PCA, 35.94 ± 4.00 weeks) were enrolled. The mean IOP with standard deviation was 16.86 ± 2.93 mm Hg; the mean CCT, 590 ± 58.26 µm. Both IOP and CCT values were found to be significantly higher in infants with lower versus higher PCA (P < 0.001). There was a statistically significant negative linear relationship between the PCA and the values of IOP and CCT, separately. CONCLUSIONS: IOP and CCT values may be higher in infants with lower PCA. Higher IOP values in these infants may be associated with higher CCT values.

Tear and serum vitamin D levels in children with allergic rhinoconjunctivitis.

BACKGROUND: Although solid cohort studies confirmed a preventative role for the anti-oxidant vitamin D in allergic asthma, a limited number of studies focused on allergic rhinoconjunctivitis (ARC). Here, we aimed to determine 25-hydroxycholecalciferol levels in tear and serum in young allergic rhinoconjunctivitis patients as compared to their apparently healthy matched controls. METHODS: In total, 22 children with allergic rhinoconjunctivitis and 31 healthy control subjects underwent serum total IgE and 25-hydroxycholecalciferol measurements. Tear levels of 25-hydroxycholecalciferol were also determined in both groups. RESULTS: The mean serum total IgE level in the ARC group (143.6±132.8IU/ml) was significantly higher than that in the control group (54.8±44.1IU/ml; p=0.03). Serum 25(OH)D levels were significantly higher in the ARC group (34.1±12.7ng/ml) than in the healthy controls (21.8±11.3ng/ml; p=0.001). CONCLUSIONS: To our knowledge, this is the first reported study to show an association between serum 25-hydroxycholecalciferol and ARC in a childhood group. Higher levels of serum 25-hydroxycholecalciferol in children with allergic rhinoconjunctivitis may indicate a possible aetiopathogenic mechanism in the development of allergic rhinoconjunctivitis. This is also the first report to examine tear fluid vitamin D levels in paediatric ARC patients.

The effect of ß receptor blockade through propranolol on corneal neovascularization.

PURPOSE: To evaluate the inhibitory effects of propranolol, a nonselective and lipophilic ß-adrenergic receptor blocker, on alkali-induced corneal neovascularization (NV). METHODS: Corneal NV was induced in 24 eyes of 24 Wistar rats using NaOH. Following alkali burn, animals were randomized into 4 groups according to topical treatment. Group I received 0.9% NaCl, Group II received preservative-free dexamethasone sodium phosphate 1 mg/mL, Group III received propranolol hydrochloride 1 mg/mL, and Group IV received 0.5 mg/mL propranolol hydrochloride drops twice a day for 7 days. The inhibitory effects of the drugs were compared as the percent areas of cornea covered by NV. Anti-vascular endothelial growth factor (VEGF) and anti-active caspase-3 immunostainings were also performed in corneal sections. RESULTS: The median percent area of corneal NV was 59% (40.3-65.6) in Group I, 25.5% (20.9-43.4) in Group II, 68.9% (36.7-78.0) in Group III, and 50.4% (42.2-63.3) in Group IV. Group III and IV did not show any difference in comparison to Group I. Group II showed a statistically significant smaller area of corneal NV compared with Group I, III, and IV (P=0.004 for each comparison). Anti-VEGF immunostaining was significantly less in Group II compared with the other groups. Anti-active caspase-3 immunostaining was not different among the treatment groups. CONCLUSIONS: Topical propranolol 1 or 0.5 mg/mL does not have a significant inhibitory effect on alkali-induced corneal NV in rats.

Retinal and choroidal thickness in children with familial Mediterranean fever.

PURPOSE: The aim of the present study was to evaluate retinal and choroidal thicknesses in children with familial Mediterranean fever (FMF). METHODS: Thirty patients with FMF and 28 healthy controls were included in the study. The thicknesses of the retina and choroid of each subject's right eye were measured at the fovea and horizontal nasal and temporal quadrants at 500-µm intervals to 1500 µm from the foveal center using spectral-domain optic coherence tomography. RESULTS: Retinal and choroidal thicknesses at the fovea did not differ between groups (p = 0.32 and p = 0.39, respectively). Horizontal nasal and temporal retinal and choroidal thickness measurements at 500-µm intervals to a distance of 1500 µm from the foveal center were also similar between the groups (all p > 0.05). CONCLUSIONS: The retinal and choroidal thicknesses of children with FMF do not differ from those of age- and sex-matched healthy controls.

Anterior chamber fixation of a posterior chamber intraocular lens: a novel technique.

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

Inhibitory effects of regorafenib, a multiple tyrosine kinase inhibitor, on corneal neovascularization.

AIM: To evaluate the inhibitory effects of regorafenib (BAY 73-4506), a multikinase inhibitor, on corneal neovascularization (NV). METHODS: Thirty adult male Sprague-Dawley rats weighing 250-300 g, were used. Corneal NV was induced by NaOH in the left eyes of each rat. Following the establishment of alkali burn, the animals were randomized into five groups according to topical treatment. Group 1 (n = 6) received 0.9% NaCl, Group 2 (n = 6) received dimethyl sulfoxide, Group 3 (n = 6) received regorafenib 1 mg/mL, Group 4 (n =6) received bevacizumab 5 mg/mL and Group 5 (n = 6) received 0.1% dexamethasone phosphate. On the 7d, the corneal surface covered with neovascular vessels was measured on photographs as the percentage of the cornea's total area using computer-imaging analysis. The corneas obtained from rats were semiquantitatively evaluated for caspase-3 and vascular endothelial growth factor by immunostaining. RESULTS: A statistically significant difference in the percent area of corneal NV was found among the groups (P <0.001). Although the Group 5 had the smallest percent area of corneal NV, there was no difference among Groups 3, 4 and 5 (P >0.005). There was a statistically significant difference among the groups in apoptotic cell density (P = 0.002). The staining intensity of vascular endothelial growth factor in the epithelial and endothelial layers of cornea was significantly different among the groups (P <0.05). The staining intensity of epithelial and endothelial vascular endothelial growth factor was significantly weaker in Groups 3, 4 and 5 than in Groups 1 and 2. CONCLUSION: Topical administration of regorafenib 1 mg/mL is partly effective for preventing alkali-induced corneal NV in rats.

Locomotor differences in Mongolian gerbils with the effects of midazolam administration in the form of eye drops.

BACKGROUND: Midazolam is a sedative-hypnotic agent with amnestic and anticonvulsant properties that can be administrated to mammals through various routes, such as intravenous, intramuscular, oral, intrathecal, rectal, and buccal. Midazolam administration in the form of eye drops through the conjunctiva is not reported in the literature. AIM: This study aims to demonstrate the possible central nervous system effects of midazolam administration as eyes drops in Mongolian gerbils. MATERIALS AND METHODS: Fourteen gerbils were randomly assigned to one of two equal sized groups. The active arm received 2 ml of 10 mg midazolam as eye drops in both eyes. Control group received a total of 2 ml of physiological saline (0.9% NaCl). We subjected the gerbils to an adapted "Open Field" to determine the possible effects on central nervous system of midazolam. Gerbils were allowed to move freely in the open field. Before and after the drug administration, locomotor activities of each gerbil have been recorded. Frequency of loss of righting reflex was quantified. RESULTS: Conjunctival midazolam administration resulted with the transient loss of righting reflex (p=0.017) and suppressed exploration motion (p=0.018) in the open field test compared to control subjects. CONCLUSIONS: In the present study, administration of conjunctival midazolam as an eye drop may affect gerbil's locomotor activities and open field behaviors. We argue that, using a sedative and anticonvulsive drug such as midazolam via conjunctival route may be useful in some clinical situations. Therefore, it could be beneficial to develop a new conjunctival formulation of midazolam. Also, there is a need for trials in humans with pharmacokinetic studies.

Inhibitory effects of topical cyclosporine A 0.05% on immune-mediated corneal neovascularization in rabbits.

BACKGROUND: We aimed to study the inhibitory effects of topical cyclosporine A (CsA) 0.05% on immune-mediated corneal neovascularization, and to compare its efficacy with those of dexamethasone 0.1% and bevacizumab 0.5%. METHODS: Immune-mediated corneal neovascularization was created in 36 right eyes of 36 rabbits. The rabbits were then randomized into four groups. Group I received CsA 0.05%, Group II received dexamethasone 0.1%, Group III received bevacizumab 0.5%, and Group IV received isotonic saline twice a day for 14 days. The corneal surface covered with neovascular vessels was measured on the photographs. The rabbits were then sacrificed and the corneas excised. Paraffin-embedded sections were stained with hematoxylin-eosin and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. RESULTS: The means of percent area of corneal neovascularization in Group I, II, III, and IV were 24.4%, 5.9%, 37.1%, and 44.1%, respectively. The inhibitory effect of CsA 0.05% was found to be better than the effect found in the bevacizumab 0.5% and control groups (p = 0.03 and p = 0.02, respectively). CsA 0.05% was found to have significantly lesser inhibitory effects on corneal neovascularization than dexamethasone 0.1% (p < 0.001). Apoptotic cell density was higher in Group III and Group IV than in Group I and Group II. There was no difference between Group I and Group II in terms of apoptotic cell density (p = 0.7). CONCLUSIONS: Topical CsA 0.05% was shown to have an inhibitory effect on immune-mediated corneal neovascularization in rabbits.

Efficacy of daptomycin on experimental methicillin-resistant Staphylococcus aureus keratitis in rabbits.

PURPOSE: We aimed to compare the efficacy of topical daptomycin (DAP) with that of vancomycin (VA) in the treatment of keratitis caused by methicillin-resistant Staphylococcus aureus (MRSA). METHODS: One hundred colony-forming unit MRSA bacteria were injected intrastromally into both corneas of 28 rabbits. Sixteen hours after injection, the rabbits' eyes were treated with 1 drop of topical DAP (10 or 50 mg/mL), VA (50 mg/mL), or isotonic saline for 19 doses. Their eyes were examined for clinical severity before and after treatment. RESULTS: The minimum inhibitory concentration values of VA and DAP against the bacterial strain were found to be 2 and 0.5 µg/mL, respectively. The mean pre- and post-treatment clinical scores of the eyes did not differ significantly among the groups. However, the mean difference between the post- and pretreatment clinical scores was significantly lower in the 50 mg/mL DAP group than in the other groups (P=0.042). A marked decrease in bacterial load was detected in all treatment groups compared to the control group (P=0.002). Although there were no significant differences in bacterial load among the treatment groups, the 50 mg/mL DAP group showed the greatest decrease. The mean % epithelial erosion rate tended to be higher in the 50 mg/mL VA group than in the other groups (P=0.31). CONCLUSIONS: Topical DAP significantly reduced the bacterial load and showed activity against MRSA comparable to that of fortified VA in this experimental model.

Linezolid versus vancomycin for the treatment of methicillin-resistant Staphylococcus aureus keratitis in rabbits.

PURPOSE: To compare the efficacy of topical linezolid (LZD) 1 mg/mL or 2 mg/mL to vancomycin (VA) 50 mg/mL for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) keratitis in rabbits. METHODS: One hundred colony-forming unit (CFU) MRSA bacteria were injected intrastromally into rabbit corneas. Sixteen hours after the injection, 24 rabbits were randomly divided into 4 groups. Rabbit eyes were treated with 1 drop of topical LZD 1 mg/mL, LZD 2 mg/mL, VA 50 mg/mL, or isotonic saline every 15 minutes for 5 doses and then every 30 minutes for 14 doses. Eyes were examined before and after the treatment using slit-lamp biomicroscopy by 2 observers blinded to the study for the determination of clinical severity. Then, corneas were harvested for the quantification of bacteria and histopathology. RESULTS: There were no differences in clinical severity among the groups before and after the treatment in each eye. The mean CFU × 10(6) of MRSA recovered from the LZD 1 mg/mL, LZD 2 mg/mL, and VA 50 mg/mL groups were significantly lower than that recovered from corneas treated with isotonic saline. There was no statistically significant difference among the treatment groups in terms of CFU × 10(6). Epithelial erosion in the VA 50 mg/mL group was significantly worse than that in the other groups. LZD 2 mg/mL group had the lowest mean epithelial erosion values. CONCLUSIONS: Topical LZD showed activity against MRSA that was comparable to fortified VA in this experimental keratitis model.

Aqueous humour and serum concentration of asymmetric dimethyl arginine in pseudoexfoliation syndrome.

OBJECTIVE: Asymmetric dimethyl arginine (ADMA) is the major endogenous inhibitor of nitric oxide synthase. ADMA is related to endothelial dysfunction and is an independent cardiovascular risk factor. This study aimed to evaluate the concentration of ADMA in aqueous humour and serum samples of patients with pseudoexfoliation (PEX) syndrome. MATERIALS AND METHODS: 21 cataract patients with PEX syndrome (PEX group) and 18 cataract patients without PEX syndrome (control group) were enrolled in the study. ADMA was measured in the aqueous humour and serum of the PEX and control groups. ELISA was used to determine the ADMA concentration. RESULTS: Mean aqueous humour ADMA concentration in the PEX group was 0.39 ± 0.07 µmol/l and in the control group was 0.34 ± 0.06 µmol/l. Mean serum ADMA concentration in the PEX group was 0.56 ± 0.21 µmol/l and in the control group was 0.44 ± 0.12 µmol/l. ADMA concentration of aqueous humour in the PEX group was significantly higher than the control group (p=0.026). Similarly, ADMA concentration of serum in the PEX group was significantly higher than the control group (p=0.039). CONCLUSIONS: The findings of the present study could suggest that ADMA might play a role in the aetiopathogenesis of PEX syndrome. Higher aqueous and serum levels of ADMA might be potential evidence of endothelial dysfunction in PEX syndrome.

Inhibitory effects of SU5416, a selective vascular endothelial growth factor receptor tyrosine kinase inhibitor, on experimental corneal neovascularization.

PURPOSE: Treatment of neovascularization in ocular diseases with vascular endothelial growth factor (VEGF) inhibition shows promising results. SU5416 is a low-molecular-weight tyrosine kinase inhibitor. It selectively inhibits the membrane-bound tyrosine kinase activity of VEGF-2 receptor (Flk-1/KDR) and blocks the intracellular signaling process. The aim of this study was to evaluate the effect of SU5416 on corneal neovascularization. METHODS: Corneas were cauterized with silver nitrate/potassium nitrate sticks in 20 eyes of 20 BALB/C mice. In the study group (n = 10), SU5416 (25 mg/kg) dissolved in dimethyl sulfoxide was given as an intraperitoneal injection in a single daily dose for 7 days. The other group of 10 mice given intraperitoneal dimethyl sulfoxide alone served as a control group. After 7 days, corneal neovascularization was evaluated using photographs captured by fluorescein angiography. Colored photographs were taken by a biomicroscope with a digital camera. Data were expressed as mean neovascular length and mean number of new vessels for each animal. The values were computed and compared between the groups. RESULTS: The mean burn stimulus intensities were not different between the groups. In the study group, the mean length of the vessels and the mean number of vessels were 0.49 ± 0.05 and 11.20 ± 1.69 mm, respectively. In the control group, the mean length of the vessels and the mean number of the vessels were 0.89 ± 0.11 and 17.80 ± 1.03 mm, respectively. There is a statistically significant difference in the mean length and the mean number of new vessels between the study and control groups (p < 0.001). CONCLUSION: Selective inhibition of VEGFR-2 (Flk-1/KDR) tyrosine kinase with SU5416 was shown to have an inhibitory effect on corneal neovascularization in this animal model. VEGFR-2 (Flk-1/KDR) tyrosine kinase inhibition may represent a different pathway for treatment of the neovascularization process in ocular pathologies. Fluorescein angiography photographs of new vessels on the cornea may provide a better evaluation of neovascularization than colored images in animal models.