Researcher:
Güleser, Ümit Yaşar

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Ümit Yaşar

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Güleser

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Güleser, Ümit Yaşar

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    PublicationOpen Access
    Evidence of mitophagy in lens capsule epithelial cells of patients with pseudoexfoliation syndrome
    (Lippincott Williams and Wilkins, 2024) N/A; Aydemir, Dilara; Sönmez, Sadi Can; Kısakürek, Zeynep Büşra; Gözel, Merve; Karslıoğlu, Melisa Zişan; Güleser, Ümit Yaşar; Şahin, Afsun; Hasanreisoğlu, Murat; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; School of Medicine; Koç University Hospital
    Purpose Pseudoexfoliation Syndrome (PEX) is a condition in which aberrant fibrillary protein builds up in various components of the eye and other extraocular tissues. In this study, we aim to investigate the functionality of intracellular auto-degradative machinery -especially mitophagy- and related genes and proteins in PEX. Methods Anterior lens capsules were obtained from cataracts patients with and without PEX to constitute the PEX group and age-matched controls during microincision cataracts surgery. PINK1-mediated mitophagy markers were evaluated on the transcriptional and translational level via RT-qPCR and immunohistochemistry analysis, respectively. Results The lens epithelial cells of PEX patients were characterized by significantly higher PINK1 gene expression compared to that of the controls (p<0.05). In terms of intensity of staining of expressed proteins, PINK1 (p<0.05), Parkin (p<0.01) and LC3B (p<0.01) were all statistically higher in PEX, compared to the controls. Conclusion Altered auto-degradative response -specifically mitophagy- is a component of increased oxidative stress in PEX patients. The role of this mechanism in emerging complications warrants further research.
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    Publication
    Case report: paracentral acute middle maculopathy following Covid- 19 vaccination
    (Gazi Eye Foundation, 2023) Güleser, Ümit Yaşar; Kesim, Cem; Hasanreisoğlu, Murat; School of Medicine; Koç University Hospital
    We report a case of paracentral acute middle maculopathy (PAMM) in association with coronavirus disease 2019 (COVID-19) vaccination. A 67-year-old male patient presented with a complaint of decreased vision in his right eye (OD) three days after receiving the Pfizer-BioNTech COVID-19 vaccine. Dilated fundus examination showed a white retinal lesion in the superior parafoveal region and optic disc edema in OD, and fundus autofluorescence (FAF) revealed hypoautofluorescence at the corresponding area. Spectral domain optical coherence tomography (SD-OCT) demonstrated the presence of a hyperreflective band along the inner nuclear layers (INL) and extending from the outer plexiform layer (OPL) to inner plexiform layer (IPL) in OD, SD-OCT was normal in his left eye (OS). Fundus fluorescein angiography (FA) showed hypofluorescence in the superior parafoveal area with late disc leakage in OD and FA was normal in OS. Current case highlights the recent severe acute respiratory syndrome coronavirus - 2 (SARS-CoV-2) vaccine as a possible cause for PAMM as a form of a rare adverse effect. However, further studies should be done to describe any association between COVID-19 vaccination and post-vaccination related retinopathies. © 2023 Gazi Eye Foundation. All rights reserved.
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    Publication
    Wearable multi-color RAPD screening device
    (SPIE-Int Soc Optical Engineering, 2023)  ; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Gülersoy, Arda; Tuzcu, Ahmet Berk; Gündüzalp, Doğa; Kavaklı, Koray; Küçüködük, Abdullah; Güleser, Ümit Yaşar; Aygün, Uğur; Hasanreisoğlu, Murat; Şahin, Afsun; Ürey, Hakan; Graduate School of Sciences and Engineering; College of Engineering; School of Medicine; Koç University Hospital
    In this work, we developed a wearable, head-mounted device that automatically calculates the precise Relative Afferent Pupillary Defect (RAPD) value of a patient. The device consists of two RGB LEDs, two infrared cameras, and one microcontroller. In the RAPD test, the parameters like LED on-off durations, brightness level, and color of the light can be controlled by the user. Upon data acquisition, a computational unit processes the data, calculates the RAPD score and visualizes the test results with a user-friendly interface.Multiprocessing methods used on GUI to optimize the processing pipeline. We have shown that our head-worn instrument is easy to use, fast, and suitable for early-diagnostics and screening purposes for various neurological conditions such as RAPD, glaucoma, asymmetric glaucoma, and anisocoria.