Browsing by Author "Guler C."

Now showing 1 - 7 of 7
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    Comparison of surgical outcomes in primary endoscopic dacryocystorhinostomy with and without silicone intubation
    (2002) Unlu H.H.; Toprak B.; Aslan A.; Guler C.
    The surgical outcome of endoscopic endonasal dacryocystorhinostomy was analyzed in 30 cases of postsaccal stenosis. Intubation with silicone tubing was used in 14 cases (46.7%) and not used in 16 cases (53.3%). Surgical success was evaluated subjectively and objectively. The patients' complaints were improved in 85.7% of cases in the intubation group, and in 81.3% of the group in which no stent was used. Postoperative endoscopic examinations revealed that the rhinostomy opening was visible in 11 cases without intubation (68.8%) and 9 cases with intubation (64.3%). Six patients in the intubation group (42.9%) had granulation tissue at the rhinostomy site. Four patients (28.6%) had complaints regarding the intubation. Considering the similar surgical success rates, and the granulation formation, patient discomfort, and cost related to intubation, we recommend endoscopic dacryocystorhinostomy without intubation as the treatment of choice in cases of chronic epiphora due to postsaccal stenosis of the lacrimal canal.
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    A histological analysis of the protective effect of ischemic preconditioning in the rat retina
    (2002) Toprak A.B.; Ozbilgin K.; Toprak V.; Tuglu I.; Guler C.
    Purpose. Ischemic preconditioning (IP) protects the retina from the damaging effect of subsequent ischemia in vivo. We aimed to investigate the histological alterations induced by the protective effect of IP to the retina. Methods. The eyes of the rats were rendered ischemic by intra-ocular pressure (IOP) elevation. IP procedure consisted of producing ischemia for 5 minutes. Sham operation was similar to IP procedure except the pressure elevation. The operational eyes of sham and IP group underwent 60 minutes of ischemia 24 hours after the first procedure. The eyes contralateral to the experimental eyes made up the control group. The eyes were histologically analysed one week after the ischemia. Results. The total retinal thickness of the sham group was significantly less than total retinal thickness of the control group (p < 0.001). There was not a significant difference between control and IP group regarding the total retinal thickness (p > 0.05). The thickness of the inner retinal layers of the sham group were significantly less than corresponding retinal layers of the control group (p < 0.001). The inner plexiform layer (IPL) and inner nuclear layer (INL) thickness values of the sham group were significantly less than same layers of the IP group (p < 0.001). Ganglion cell layer (GCL) thickness of the IP group was significantly less than GCL thickness of the control group (p < 0.001). IPL thickness of the IP group was significantly less than that of control group's (p < 0.05). The GCL and total retinal thickness of the IP group were significantly more than thickness of the corresponding layers of the sham group (p < 0.05). Conclusion. IP considerably protects inner retinal layers from subsequent ischemic damage in a high IOP ischemic model. This endogenous process could further be utilized to tailor specific neuroprotective strategies for retinal cells.
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    Trypan blue staining of the anterior capsule under an air bubble with a modified cannula
    (Slack Incorporated, 2003) Toprak A.B.; Erkin E.F.; Guler C.
    To attain good visibility of the anterior capsule in the advanced or white cataract, trypan blue 0.1% is used to stain the anterior capsule. The dye is usually injected under an air bubble. However, it is difficult to inject the dye properly due to capillary forces. An ordinary anterior chamber cannula was modified and its coverage area increased to facilitate the staining of the anterior capsule under an air bubble. The anterior capsule was stained properly by using the modified cannula in all of the cases.
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    Tear function changes of postmenopausal women in response to hormone replacement therapy
    (2003) Kuscu N.K.; Toprak A.B.; Vatansever S.; Koyuncu F.M.; Guler C.
    Objective: The goal of this study was to search the effect of hormone replacement therapy (HRT) on tear function changes in postmenopausal women. Methods: Following initial ophtalmic evaluation and tear sample collection, the subjects were given daily 0.625 mg conjugated estrogen, and either continuous combined or cyclic 5 mg medroxyprogesterone acetate was added. Eye examination included visual acuity, slit-lamp examination, fundus examination, tonometry, Schirmer's test, and break up time (BUT) evaluation. Six months later, control examination was done and repeat tear samples were obtained. Tear immune globulin A (IgA) and lysozyme levels were measured by gel electrophoresis. The pictures of the bands were evaluated by digital image analysis with Scion Image program. Results: Conjunctival vascular congestion, laxity and corneal desquamation did not change before and after HRT (P>0.05). A significant improvement was noted in meibomian gland inflammation (P=0.034). We have not observed any significant difference in burning, foreign body sensation, and tearing (P>0.05). In addition, no significant difference was noted in BUT (P=0.370) and Schirmer's test values (P=0.271). Though both lysozyme and IgA levels were elevated following the therapy, only IgA levels increased significantly (P=0.04). Conclusion: HRT decreased meibomian gland inflammation and increased tear lysozyme and IgA levels in postmenopausal women. © 2002 Elsevier Science Ireland Ltd. All rights reserved.
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    Cross-validation of the Turkish version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25)
    (2005) Toprak A.B.; Eser E.; Guler C.; Baser F.E.; Mayali H.
    Purpose: To test the validity and reliability of the Turkish version of the self-administered form of the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25). Methods: Patients with no limitations to respond to a health status interview and affected by a chronic eye disease were enrolled. The Turkish versions of the abbreviated form of World Health Organization Quality of Life (WHOQOL-BREF) and the NEI-VFQ 25 instruments were administered to all participants. Results: The mean (SD) age of the participants was 60.9 (14.5) years. There were 61 patients with one of the following conditions: Cataract (57.4%), diabetic retinopathy (13.2%), age related macular degeneration (ARMD) (11.4%), glaucoma (9.8%) and degenerative myopia (8.2%). The Cronbach alpha of the overall scale was 0.97; the Cronbach alpha ranged from 0.94 to 0.78 for the subscales. The physical, psychological, environmental and social domains of the WHOQOL-BREF had fair to good correlations with the NEI-VFO 25 (r = 0.68 to r = 0.26), which indicated a sufficient convergent validity. Patients with lower visual acuity (VA) had lower index scores than those with higher VA (p = 0.001), which showed a sufficient responsiveness. Conclusion: Statistical analysis showed that Turkish version of the NEI-VFQ is a valid and reliable instrument to measure vision-related quality of life in patients with chronic eye diseases. Copyright © Taylor & Francis Inc.
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    Numerical solutions of a class of non-linear ordinary differential equations in Hermite series
    (Serbian Society of Heat Transfer Engineers, 2019) Guler C.; Kaya S.O.; Sezer M.
    The purpose of this paper is to present a Hermite polynomial approach for solving a high-order ODE with non-linear terms under mixed conditions. The method we used is a matrix method based on collocation points together with truncated Hermite series and reduces the solution of equation to solution of a matrix equation which corresponds to a system of non-linear algebraic equations with unknown Hermite coefficients. In addition, to illustrate the validity and applicability of the method, some numerical examples together with residual error analysis are performed and the obtained results are compared with the existing result in literature. © 2019 Society of Thermal Engineers of Serbia.
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    Cellular Biomarkers in Mytilus galloprovincialis L. (Mediterranean Mussels) from Izmir Bay (Turkey)
    (Springer, 2022) Katalay S.; Ayhan M.M.; Guler C.; Aldag C.; Kilic T.; Yavasoglu N.U.K.
    In this study, cellular biomarkers and heavy metal concentration in the Mytilus galloprovincialis L. (Mediterranean mussels) collected from eight sites of Izmir Bay (Turkey) were determined to reveal water pollution for the first time in these stations. Results show that heavy metals (As, Cu, Hg, Zn, Cd, Sn, Pb) have been specified in mussels’ tissues collected from all stations. According to GST, SOD, CAT activities, and TBARS contents, mussels in the outer bay have exposed more oxidative stress than the ones in the inner bay. Digestive gland tissues of them were showed more inhibition at AChE levels than gills. Also, abnormal nucleus rates and micronucleus frequencies (MN) were found to be higher in the inner bay than in the outer bay. This study showed that heavy metal pollution in different levels is an environmental issue on the Izmir Bay. Especially the coastal regions of the bay have been extremely affected by anthropogenic effects due to growing population. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.