Ibrahim Kocer - Academia.edu (original) (raw)

Papers by Ibrahim Kocer

RSC Advances, 2017

A magnetic sorbent based on monodisperse-porous silica microspheres was developed for His-tagged ... more A magnetic sorbent based on monodisperse-porous silica microspheres was developed for His-tagged protein purification by immobilized metal affinity chromatography.

Turkiye Klinikleri Journal of Ophthalmology, 2000

Turkish Journal of Medical Sciences, 1997

Journal of Retina-Vitreous, 2020

We aimed to evaluate the serum Endocan (endothelial cell-specifi c molecule-1, ESM-1) levels in p... more We aimed to evaluate the serum Endocan (endothelial cell-specifi c molecule-1, ESM-1) levels in patients with retinal vein occlusion (RVO) and compare them with those of the control group to determine the correlation with illness activity Materials and Methods: Venous blood samples were obtained from 43 patients with RVO and 43 healthy subjects who attended Atatürk University Medical Faculty Eye Diseases Policlinic between 1 June 2015 and 1 September 2015. Thirty-one of the 43 patients had branch RVO, and 12 of the patients had central RVO. Results: The mean age of the patients was 62±10,19, and the mean age of the control group was 60,27±5,53. Twenty-four of the 43 patients (54,5%) suffered from RVO in their right eyes, and 19 of the patients (43,2%) suffered from RVO in their left eyes. No statically signifi cant differences in age and sex were observed between the patients and the control group. All patients had hypertension, and 15 patients had diabetes mellitus. Thirty 30 patients (68,2%) had ischemic-type RVO, 13 patients (29,5%) had nonischemic-type RVO. Thirty-one patients (70,5%) had branch RVO, and 12 patients (27,3%) had central RVO. Statically signifi cant differences in serum level of ESM-1 were observed between the patients and the control group (p<0.05). A comparison of the ischemic-type RVO and the non-ischemic-type RVO in the patients group revealed statically signifi cant differences in the serum ESM-1 level (p=0,003). Conclusion: The comparison of the serum ESM-1 levels in patients with RVO with the control group can be a guiding parameter for showing the severity of disease.

DergiPark (Istanbul University), Sep 29, 2016

Purpose To compare the visual field changes of medically or surgically regulated ocular tensions ... more Purpose To compare the visual field changes of medically or surgically regulated ocular tensions of patients with open angle glaucoma followed up for two years Materials and Methods: Twenty one medically and 17 surgically regulated open angle glaucoma patients were included the study. Complete ophthalmic and gonioscopic examinations are made. For all patients at the beginning and every three months, visual field analysis with Humphrey 30-2 standard test was also performed. For diagnosing visual field changes we used glaucoma progression analysis statistical program of Humphrey Visual Field Analyser750 II-A (Carl Zeiss Meditec-USA).We used t-test for calculating age difference and Fisher's �2 test to compare visual field worsening. To compare the visual acuities and ocular tensions between two groups, we were used unpaired t-test. Result: We did not find visual field worsening difference between medical and surgical group(p=0.49, p>0.05). Özet Amaç: Oküler tansiyonları cerrahi veya medical tedaviyle regüle olan primer açık açılı glokomlu olguların görme alanı değişikliklerinin iki yıllık takipte farklılık gösterip göstermediğinin tespit edilmesi. Materyal ve Method: 2011-20013 yılları arasında kliniğimizde primer açık açılı glokom nedeniyle opera edilmiş 17 ve tıbbi tedavi gören 21 hasta dahil edildi. Rutin oftalmolojik muayeneleri ve ön kamara açısının değerlendirilmesi yapıldı. Tüm hastaların başlangıç ve her 3 ayda bir Humphrey 30-2 görme alanı muayeneleri yapıldı. Görmealanları yanında görmealanı değişimlerinin istatistiksel olarak değerlendirilmesi için cihazın glokom ilerleme analizi programı kullanıldı. Hastaların yaşları arasındaki fark t-testi, görme alanındaki kötüleşmelerin karşılaştırılması ise Fisher'inkesin K 2 testiyle yapıldı. Vizyon ve tansiyonlar her iki grupta karşılaştırılırken unpaired t-test kullanıldı. Sonuç: Her iki gruptada görülen görme alanı kötüleşmelerini gösteren kötüleşme analizleri arasında anlamlı birfark görülmedi (p=0.49, p>0.05).

Pain Clinic, Jun 1, 2003

ABSTRACT To investigate the levels of adrenomedullin (ADM) and lipoprotein (a) [Lp(a)] and their ... more ABSTRACT To investigate the levels of adrenomedullin (ADM) and lipoprotein (a) [Lp(a)] and their correlation and interaction with disease activity in Behcet's disease (BD), we measured the levels of ADM, Lp(a), ?1-antitrypsin (AAT), ?2-macroglobulin (AMG), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) in 35 patients (15 men) with BD (15 active) and 20 healthy volunteers (12 men) serving as controls. The disease activity was evaluated by clinical manifestations (oral aphthous ulcer, genital ulceration, skin lesions and uveitis) and by laboratory investigations (ESR and CRP). The levels of ADM, Lp(a), AAT, AMG, ESR, and CRP were found to be increased in patients with BD compared with those of the control group. The mean levels of those parameters in patients with active BD were significantly higher than those of the patients with inactive BD and of the control group. Similarly, the mean values of those parameters in the inactive BD group were higher than those of the control group. There were no statistically significant correlations between age and Lp(a), ADM, ESR, CRP, AAT or AMG levels. A significant positive correlation was present between ADM and CRP (r = 0.774, p < 0.001), ADM and ESR (r = 0.683, p < 0.001), Lp(a) and CRP (r = 0.572, p < 0.001), Lp(a) and ESR (r = 0.495, p < 0.01), Lp(a) and ADM (r = 0.702, p < 0.001). However, no statistically significant correlation was observed between Lp(a) and ADM with AAT or AMG levels.These data show that increases in ADM, Lp(a), ESR, CRP, AAT and AMG are present in patients with BD, that increases in ADM levels might be due to increased Lp(a) levels, and that the plasma ADM and serum Lp(a) levels are useful markers for evaluating the severity of BD.

Turkiye Klinikleri Journal of Ophthalmology, 2001

Bourgeut tekniði (1), klasik dakriosistorinostomi (DSR) teknikleri arasýnda en yaygýn olarak uygu... more Bourgeut tekniði (1), klasik dakriosistorinostomi (DSR) teknikleri arasýnda en yaygýn olarak uygulanan yöntem olmuþ (2,3); birçok klinikte de baþarý ile uygulanmýþtýr (4-8).

Tohoku Journal of Experimental Medicine, 2008

Retinal vein occlusion is an important cause of visual loss. Several ocular and systemic conditio... more Retinal vein occlusion is an important cause of visual loss. Several ocular and systemic conditions have been reported for retinal vein occlusion. The pathogenesis of thrombus formation in the retinal vein, which results in retinal vein occlusion, is unclear. The aim of this study was to investigate the correlation between increased serum leptin levels and the occurrence of retinal vein occlusion (RVO). The study group consisted of 40 patients with RVO (58.1 ± 6 years old; 17 males and 23 females): 15 patients with central RVO, 23 with branch RVO, and 2 with hemispheric RVO. The patients who had any ocular or systemic pathology were not included in the study. The control group consisted of 40 healthy individuals of similar gender, age, date and type of health survey, and geographic region. The blood samples of the RVO patients (n = 40) and controls (n = 40) were obtained antecubitally. Leptin levels were measured by an enzyme-linked immunosorbent assay (ELISA) method, and Student's t-test was used to determine differences between the groups. The mean serum leptin levels were 12.5 ± 1.64 ng/ml in patients with RVO and 8.4 ± 1.22 ng/ ml in the control subjects; namely, the mean serum leptin levels were significantly higher in the patients with RVO (p < 0.001). These results suggest that leptin may be involved in the pathogenesis of venous thrombosis in the retina probably through its effects on homeostasis of the vessel wall. leptin; retinal vein occlusion; thrombosis; homeostasis.

Perceptual and Motor Skills, Oct 1, 2002

The effects of unilateral forced nostril breathing on the intraocular pressures of right and left... more The effects of unilateral forced nostril breathing on the intraocular pressures of right and left eyes was studied in 24 male and 26 female right-handed adults. In men, the forced breathing through both the right and left nostrils significantly decreased the intraocular pressures of both right and left eyes. For women, the forced breathing through right nostril did not affect the intraocular pressures of right and left eyes, and the forced breathing through lefr nostril also had no effect on the intraocular pressure of rlShr eye, although it decreased the intraocular pressure of left eye significantly. These resulrs show that unilateral forced nostril breathing decreases intraocular pressure especially in men, perhaps increasing sympathetic nenlous system activity.

International Journal of Ophthalmology, Oct 18, 2016

• Toinvestigatethemalondialdehyde (MDA)levels, paraoxonase1 (PON1) activity and 8-hydroxy 2deoxyg... more • Toinvestigatethemalondialdehyde (MDA)levels, paraoxonase1 (PON1) activity and 8-hydroxy 2deoxyguanosine(8-OHdG)levelsintheprimaryopenangle glaucoma(POAG)patient.Bloodsamplesfrom52healthy individualsand53patientswithPOAGwereanalyzedfor MDA and 8-OHdG by high-performance liquid chromatography(HPLC)andPON1byspectrophotometry. Thedataobtainedwereanalyzedstatistically.MDAlevels were10.46依8.4and4.70依1.79 滋mol;PON1levelswere121依 39.55and161.62 依60.22U/mL;and8-OHdGvalueswere 1.32 依0.53/10 6 dGand0.47 依0.27/10 6 dGinthePOAG patients and the control group, respectively. The differencewassignificantinMDAlevels,8-OHdGlevels andPON1activityinPOAGpatientsincomparisonwith controls (<0.001).Weconcludedthattheobserved increaseinMDAand8-OHdGlevelsmaybecorrelated withdecreasedPON1activity.Oxidativestressplaysan importantroleinglaucomadevelopment.

European Journal of Ophthalmology, 2003

PURPOSE. To investigate the efficacy of L-carnitine in preventing retinal injury followed by isch... more PURPOSE. To investigate the efficacy of L-carnitine in preventing retinal injury followed by ischemia-reperfusion. METHODS. The eyes of 34 guinea pigs were used in this experiment. The guinea pigs were divided into two groups: the first group (n= 17) was given L-carnitine intraperitoneally (500mg/kg) and second group (n=17) received the same dose of saline solution. Under general anesthesia, peritomy was performed. Retro-orbital tissues were ligated for 90 minutes and ischemia was induced, followed by 4 hours of reperfusion. One of the enucleated eye was stained with hematoxylin and eosin (H&E) and retinal thicknesses were evaluated. Thiobarbituric acid reactive substances (TBARS) levels were determined in the retina of the other eye. RESULTS. Mean TBARS levels in retinal tissue were found lower in L-carnitine group (2.77 ± 0.55 µM) than in the control group (6.57 ± 1.19 µM), (p<0.01). On the other hand, mean retinal thickness was found to be increased in the control group (47.47 ± 5.62 µm) when compared to the L-carnitine group (26.52 ± 4.65 µm), (p<0.01). In correlation analysis, significantly positive relationships were found between retinal TBARS level and retinal thickness both in the control and L-carnitine groups (r=0.981, p<0.01 and r= 0.967, p<0.01 respectively). CONCLUSIONS. L-carnitine is effective in preventing retinal injury followed by ischemia-reperfusion.

Investigative Ophthalmology & Visual Science, Oct 8, 2015

PURPOSE. To evaluate retinal nerve fiber layer (RNFL) thickness in early-stage diabetic retinopat... more 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 earlystage 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 earlystage DR patients with VDD.

Electronic journal of general medicine, Apr 15, 2009

Aim: We investigated the association of mean platelet volume (MPV) with the degree of retinopathy... more Aim: We investigated the association of mean platelet volume (MPV) with the degree of retinopathy in patients with diabetes mellitus (DM). Methods: Ninety patients with diabetic retinopathy (DRP) and 30 healthy individuals were included in the study. Diabetic patients included 30 background, 30 non-proliferative and 30 proliferative diabetic retinopathy cases. Complete blood count, intra-and intergroup comparisons of MPV values were performed. Results: Mean values for MPV in patients with background, nonproliferative and proliferative DRP were 7.76±0.72 fL, 7.94±0.61 fL and 8.18±0.89 fL, respectively. MPV values of patients with background DRP was not significantly different from that of the control group and patients with non-proliferative and proliferative DRP as well. However, MPV values of patients with proliferative DRP were significantly higher than the values of control group (p< 0.05). A significant correlation was found between the degree of retinopathy and mean values of MPV in diabetic patients (r= 0.214, p< 0.05). Conclusions: We found an association between the degree of retinopathy and mean values of MPV. This finding suggests a role for platelets in the pathogenesis of vascular complications and that mean platelet volume would be useful in monitoring the disease progression.

PubMed, 2002

The aims of this study were to assess whether the increased oxidative stress in affected tissues ... more The aims of this study were to assess whether the increased oxidative stress in affected tissues is reflected by serum lipid peroxidation and to check for alterations in serum levels of extracellular antioxidants and antioxidant enzyme activities in patients with Behcet's disease (BD). Serum malondialdehyde (MDA) and ceruloplasmin (Cp) levels and CuZn-superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GSH-Px) activities were increased, while serum transferrin (Trf) levels were diminished in patients with active ocular BD (n = 19), inactive ocular BD (n=18), and nonocular BD (n=15), compared to healthy controls (n = 20). Serum MDA levels in patients with active ocular BD and nonocular BD were significantly higher than in the inactive ocular BD group. Patients with active ocular BD also had significantly higher serum Cu-Zn SOD activities, compared to the inactive ocular BD. Erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) levels were higher in patients with active ocular BD, inactive ocular BD, and nonocular BD, compared to the control group. In addition, patients with active ocular BD and nonocular BD had significantly higher ESR and serum CRP levels, compared to the inactive ocular BD group. Serum albumin concentrations showed no significant differences among the BD patients and controls. The authors speculate that in BD patients, serum superoxide radicals may be dismutated to H2O2 by increased CuZn-SOD activity and the conversion of H2O2 to hydroxyl radical may be enhanced by iron, owing to diminished serum Trf; these mechanisms may contribute to the increased serum lipid peroxidation.

Journal of Laryngology and Otology, Jul 1, 1997

A case of a large dentigerous cyst containing a canine tooth in the maxillary antrum is presented... more A case of a large dentigerous cyst containing a canine tooth in the maxillary antrum is presented. This case is of interest due because of its extensiveness and thepresence of a canine tooth in the roof of the maxillary sinus. In addition, this caused aright-sided epiphora. Enucleation of the cyst containing the ectopic tooth was made.

European Journal of Ophthalmology, Nov 1, 2004

PURPOSE. To determine the antioxidant role of vitamin E (VE) (10 mg/kg/day) against radiationindu... more PURPOSE. To determine the antioxidant role of vitamin E (VE) (10 mg/kg/day) against radiationinduced cataract in lens after total-cranium irradiation of rats with a single dose of 5 Gy. METHODS. Sprague-Dawley rats were divided into three groups. Group 1 did not receive VE or irradiation but received both 0.1 ml physiologic saline intraperitoneally and sham irradiation (control group). Group 2 received to total cranium 5 Gy of gamma irradiation as a single dose (RT group) plus 0.1 ml physiologic saline intraperitoneally. Group 3 received irradiation to total cranium plus 10 mg/kg/day VE (RT+VE group). The rats were irradiated using a cobalt-60 teletherapy unit. Chylack's cataract classification (1) was used in this study. At the end of 10 days, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes (the activity of superoxide dismutase [SOD], glutathione peroxidase [GSH-Px]) and lipid peroxidation level (malondialdehyde [MDA]). RESULTS. While grade 1 cataract development was detectable in seven rats in the RT group, it was detectable only in two rats in the RT+VE group, whereas none of the rats in the control group exhibited any biomicroscopic change in their lenses. MDA level and GSH-Px activity in the rat lens in the RT group was significantly higher than in the control group. SOD activity in the RT group was lower than in the control group. The activity of SOD and GSH-Px enzymes was higher in the RT+VE group, but MDA level was lower in the RT+VE group when compared with the RT group. CONCLUSIONS. Vitamin E has a protective effect on radiation-induced cataract by decreasing oxidative stress.

Neurosurgical Review, Feb 8, 2008

Our aim was to determine the effects of vitamin E and L-carnitine supplementation, individually o... more Our aim was to determine the effects of vitamin E and L-carnitine supplementation, individually or in combination, on radiation-induced brain and retinal damages in a rat model. Group 1 received no treatment (control arm). Group 2 received a total dose of 15 Gy external radiotherapy (RT) to whole brain by Cobalt-60 teletherapy machine. Groups 3, 4, and 5 received irradiation plus 40 kg(-1) day(-1) Vitamin E or 200 mg kg(-1)day(-1) L-carnitine alone or in combination. Brain and retinal damages were histopathologically evaluated by two independent pathologists. Antioxidant enzyme levels were also measured. Radiation significantly increased brain and retinal damages. A significant increase in malondialdehyde levels as well as a decrease in superoxide dismutase and catalase enzymes in brain was found in group 2. Separate administration of Vitamin E+RT and L-carnitine+RT significantly reduced the severity of brain and retinal damages and decreased the malondialdehyde levels and increased the activity of superoxide dismutase and catalase enzymes in the brain. The findings of current study support the antioxidant and radioprotective roles of vitamin E and L-carnitine. However, the combined use of Vitamin E and L-carnitine plus irradiation interestingly did not exhibit an additive radioprotective effect.

Japanese Journal of Ophthalmology, Sep 1, 2004

Ionizing radiation, such as X-and γ-rays and ultraviolet light, is known to be a cataractogenic f... more Ionizing radiation, such as X-and γ-rays and ultraviolet light, is known to be a cataractogenic factor in rat lenses. 1-3 The destructive action of ionizing radiation is predominantly due to reactive oxygen species (ROS), including the superoxide radical (O • 2 Ϫ), the hydroxyl radical (OH Ϫ), and hydrogen peroxide (H 2 O 2), generated by the decomposition of water. Superoxide dismutase (SOD) enzyme catalyzes the dismutation of O • 2 Ϫ into H 2 O 2. H 2 O 2 can then be transformed into H 2 O and O 2 by the enzymes catalase (CAT) and glutathione peroxidase (GSH-Px). One of the indices of oxidative damage is the level of malondialdehyde (MDA), which is formed as an end product of lipid peroxidation. 1,2 Ginkgo biloba extract was prepared from the leaves of the Ginkgo biloba tree according to a well-defined procedure. This extract has been reported to be a potent