Browsing by Author "Can, Ozge"

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Comparison of a novel antigen detection test with reverse transcription polymerase chain reaction assay for laboratory diagnosis of SARS-CoV-2 infection
(SPRINGER HEIDELBERG, 2022-01-01) Cirit, Osman Sezer; Mutlu, Esvet; Sancak, Banu; Kocagoz, Tanil; Can, Ozge; Cicek, Candan; Sayiner, Ayca Arzu; Appak, Ozgur; Uyar, Neval Yurttutan; Kulah, Canan; Cicek, Aysegul Copur; Ozgumus, Osman Birol; Altintop, Yasemin Ay; Saatci, Esma; Karsligil, Tekin; Zer, Yasemin; Ozen, Nevgun Sepin; Cekin, Yesim; Karahan, Zeynep Ceren; Evren, Ebru; Karakoc, Ayse Esra; Orhan, Sultan Gulbahce; Mutlu, Derya; Bozdemir, Tugba; Cayci, Yeliz Tanriverdi; Cinar, Canberk; Tasbakan, Meltem; Mert, Merve; Cinar, Ece; Kutsoylu, Oya Ozlem Eren; Kocagoz, Sesin; Erturk, Ayse; Celik, Ilhami; Mete, Ayse Ozlem; Eneyli, Muge Gunalp; Akdemir, Irem; Karakok, Taliha; Inan, Dilara; Atilla, Aynur; Taflan, Sevket Onur; Yoruk, Kagan Etka
Molecular diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time reverse transcription polymerase chain reaction (RT-PCR) in respiratory specimens is considered the gold standard method. This method is highly sensitive and specific but it has some limitations such as being expensive and requiring special laboratory equipment and skilled personnel. RapidFor (TM) Antigen Rapid Test Kit is a commercially available Ag-RDT which is produced in Turkey and designed to detect the nucleocapsid antigen of SARS-CoV-2 in nasopharyngeal swab samples. The aim of this study was to evaluate the performance of this novel SARS-CoV-2 antigen detection considering the RT-PCR method as the gold standard. Four hundred forty-four nasopharyngeal swab samples which were collected from the patients who met clinical criteria of COVID-19 from ten centers in Turkey between September 2020 and February 2021 were included in the study. All the nasopharyngeal swab samples were tested for SARS-CoV-2 RNA using commercial RT-PCR kits (Bioeksen and A1 Lifesciences, Istanbul, Turkey) according to the manufacturer's instructions. Viral loads were assessed according to the cycle threshold (Ct) values. RapidFor (TM) SARS-CoV-2 antigen test (Vitrosens Biotechnology, Istanbul, Turkey) was used to investigate the presence of SARS-CoV-2 antigen in all samples following the manufacturer's instructions. Out of 444 nasopharyngeal swab samples tested, 346 (77.9\%) were positive and 98 (22.1\%) were negative for SARS-CoV-2 RNA by RTPCR. Overall sensitivity of the RapidFor (TM). Antigen Rapid Test Kit was 80.3\% whereas specificity was found to be 87.8\%. Positivity rate of rapid antigen test in samples with Ct values over 25 and below 30 was 82.7\%, while it increased to 95.7\% in samples 20 <= Ct < 25 and reached 100\% in samples with Ct values below 20. RapidFor (TM) SARS-CoV-2 Ag test might be a good choice in the screening of symptomatic and asymptomatic patients and their contacts for taking isolation measures early, with advantages over RT-PCR as being rapid, easy and being applicable in every laboratory and even at point of care.
IDH-mutant glioma specific association of rs55705857 located at 8q24.21 involves MYC deregulation
(NATURE PUBLISHING GROUP, 2016-01-01) Oktay, Yavuz; Ulgen, Ege; Can, Ozge; Akyerli, Cemaliye B.; Yuksel, Sirin; Erdemgil, Yigit; Durasi, I. Melis; Henegariu, Octavian Ioan; Nanni, E. Paolo; Selevsek, Nathalie; Grossmann, Jonas; Erson-Omay, E. Zeynep; Bai, Hanwen; Gupta, Manu; Lee, William; Turcan, Sevin; Ozpinar, Aysel; Huse, Jason T.; Sav, M. Aydin; Flanagan, Adrienne; Gunel, Murat; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
The single nucleotide polymorphism rs55705857, located in a non-coding but evolutionarily conserved region at 8q24.21, is strongly associated with IDH-mutant glioma development and was suggested to be a causal variant. However, the molecular mechanism underlying this association has remained unknown. With a case control study in 285 gliomas, 316 healthy controls, 380 systemic cancers, 31 other CNS-tumors, and 120 IDH-mutant cartilaginous tumors, we identified that the association was specific to IDH-mutant gliomas. Odds-ratios were 9.25 (5.17-16.52
Iodine Status in Turkish Populations and Exposure to Iodide Uptake Inhibitors
(PUBLIC LIBRARY SCIENCE, 2014-01-01) Ozpinar, Aysel; Kelestimur, Fahrettin; Songur, Yildiran; Can, Ozge; Valentin, Liza; Caldwell, Kathleen; Arikan, Ender; Unsal, Ibrahim; Serteser, Mustafa; Inal, Tamer; Erdemgil, Yigit; Coskun, Abdurrahman; Bakirci, Nadi; Sezgin, Ozlem; Blount, Ben
Perchlorate, nitrate, and thiocyanate are competitive inhibitors of the sodium iodide symporter of the thyroid membrane. These inhibitors can decrease iodine uptake by the symporter into the thyroid gland and may disrupt thyroid function. This study assesses iodine status and exposure to iodide uptake inhibitors of non-pregnant and non-lactating adult women living in three different cities in Turkey (Istanbul, Isparta and Kayseri). We measured iodine and iodide uptake inhibitors in 24-hr urines collected from study participants (N = 255). All three study populations were mildly iodine deficient, with median urinary iodine (UI) levels of 77.5 mu g/L in Istanbul, 58.8 mu g/L in Isparta, and 69.8 mu g/L in Kayseri. Perchlorate doses were higher in the study population (median 0.13 mu g/kg/day), compared with a reference population (median 0.059 mu g/kg/day), but lower than the U. S. EPA reference dose (0.7 mu g/kg/day). Urinary thiocyanate levels increased with increasing exposure to tobacco smoke, with non-smokers (268 mu g/L) significantly lower than light smokers (1110 mu g/L), who were significantly lower than heavy smokers (2410 mu g/L). This pilot study provides novel data indicating that study participants were moderately iodine deficient and had higher intakes of the iodide uptake inhibitor perchlorate compared with a reference population. Further investigation is needed to characterize the thyroid impact resulting from iodine deficiency coupled with exposure to iodide uptake inhibitors such as perchlorate, thiocyanate and nitrate.
Melatonin in preservation solutions prevents ischemic injury in rat kidneys
(PUBLIC LIBRARY SCIENCE, 2022-01-01) Coskun, Abdurrahman; Yegen, Cumhur; Arbak, Serap; Attaallah, Wafi; Gunal, Omer; Elmas, Merve Acikel; Ucal, Yasemin; Can, Ozge; Bas, Banu; Yildirim, Zeynep; Seckin, Ismail; Demirci, Sibel; Serteser, Mustafa; Ozpinar, Aysel; Belce, Ahmet; Basdemir, Gulcin; Moldur, Derya Emel; Derelioglu, Ecenur Izzete; Yozgatli, Tahir Koray; Erdemgil, Yigit; Unsal, Ibrahim
Transplantation is lifesaving and the most effective treatment for end-stage organ failure. The transplantation success depends on the functional preservation of organs prior to transplantation. Currently, the University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) are the most commonly used preservation solutions. Despite intensive efforts, the functional preservation of solid organs prior to transplantation is limited to hours. In this study, we modified the UW solution containing components from both the UW and HTK solutions and analyzed their tissue-protective effect against ischemic injury. The composition of the UW solution was changed by reducing hydroxyethyl starch concentration and adding Histidine/Histidine-HCI which is the main component of HTK solution. Additionally, the preservation solutions were supplemented with melatonin and glucosamine. The protective effects of the preservation solutions were assessed by biochemical and microscopical analysis at 2, 10, 24, and 72 h after preserving the rat kidneys with static cold storage. Lactate dehydrogenase (LDH) activity in preservation solutions was measured at 2, 10, 24, and 72. It was not detectable at 2 h of preservation in all groups and 10 h of preservation in modified UW+melatonin (mUW-m) and modified UW+glucosamine (mUW-g) groups. At the 72nd hour, the lowest LDH activity (0.91 IU/g (0.63-1.17)) was measured in the mUW-m group. In comparison to the UW group, histopathological damage score was low in modified UW (mUW), mUW-m, and mUW-g groups at 10, 24, and 72 hours. The mUW-m solution at low temperature was an effective and suitable solution to protect renal tissue for up to 72 h.
Mutations and Copy Number Alterations in IDH Wild-Type Glioblastomas Are Shaped by Different Oncogenic Mechanisms
(MDPI, 2020-01-01) Ulgen, Ege; Karacan, Sila; Gerlevik, Umut; Can, Ozge; Bilguvar, Kaya; Oktay, Yavuz; B. Akyerli, Cemaliye; K. Yuksel, Sirin; E. Danyeli, Ayca; Tihan, Tarik; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
Little is known about the mutational processes that shape the genetic landscape of gliomas. Numerous mutational processes leave marks on the genome in the form of mutations, copy number alterations, rearrangements or their combinations. To explore gliomagenesis, we hypothesized that gliomas with different underlying oncogenic mechanisms would have differences in the burden of various forms of these genomic alterations. This was an analysis on adult diffuse gliomas, but IDH-mutant gliomas as well as diffuse midline gliomas H3-K27M were excluded to search for the possible presence of new entities among the very heterogenous group of IDH-WT glioblastomas. The cohort was divided into two molecular subsets: (1) Molecularly-defined GBM (mGBM) as those that carried molecular features of glioblastomas (including TERT promoter mutations, 7/10 pattern, or EGFR-amplification), and (2) those who did not (others). Whole exome sequencing was performed for 37 primary tumors and matched blood samples as well as 8 recurrences. Single nucleotide variations (SNV), short insertion or deletions (indels) and copy number alterations (CNA) were quantified using 5 quantitative metrics (SNV burden, indel burden, copy number alteration frequency-wGII, chromosomal arm event ratio-CAER, copy number amplitude) as well as 4 parameters that explored underlying oncogenic mechanisms (chromothripsis, double minutes, microsatellite instability and mutational signatures). Findings were validated in the TCGA pan-glioma cohort. mGBM and ``Others{''} differed significantly in their SNV (only in the TCGA cohort) and CNA metrics but not indel burden. SNV burden increased with increasing age at diagnosis and at recurrences and was driven by mismatch repair deficiency. On the contrary, indel and CNA metrics remained stable over increasing age at diagnosis and with recurrences. Copy number alteration frequency (wGII) correlated significantly with chromothripsis while CAER and CN amplitude correlated significantly with the presence of double minutes, suggesting separate underlying mechanisms for different forms of CNA.
Post-translational modifications of transthyretin affect the triiodonine-binding potential
(WILEY, 2015-01-01) Henze, Andrea; Homann, Thomas; Serteser, Mustafa; Can, Ozge; Sezgin, Ozlem; Coskun, Abdurrahman; Unsal, Ibrahim; Schweigert, Florian J.; Ozpinar, Aysel
Transthyretin (TTR) is a visceral protein, which facilitates the transport of thyroid hormones in blood and cerebrospinal fluid. The homotetrameric structure of TTR enables the simultaneous binding of two thyroid hormones per molecule. Each TTR subunit provides a single cysteine residue (Cys(10)), which is frequently affected by oxidative post-translational modifications. As Cys(10) is part of the thyroid hormone-binding channel within the TTR molecule, PTM of Cys(10) may influence the binding of thyroid hormones. Therefore, we analysed the effects of Cys(10) modification with sulphonic acid, cysteine, cysteinylglycine and glutathione on binding of triiodothyronine (T3) by molecular modelling. Furthermore, we determined the PTM pattern of TTR in serum of patients with thyroid disease by immunoprecipitation and mass spectrometry to evaluate this association in vivo. The in silico assays demonstrated that oxidative PTM of TTR resulted in substantial reorganization of the intramolecular interactions and also affected the binding of T3 in a chemotype- and site-specific manner with S-glutathionylation as the most potent modulator of T3 binding. These findings were supported by the in vivo results, which indicated thyroid function-specific patterns of TTR with a substantial decrease in S-sulphonated, S-cysteinylglycinated and S-glutathionylated TTR in hypothyroid patients. In conclusion, this study provides evidence that oxidative modifications of Cys(10) seem to affect binding of T3 to TTR probably because of the introduction of a sterical hindrance and induction of conformational changes. As oxidative modifications can be dynamically regulated, this may represent a sensitive mechanism to adjust thyroid hormone availability.
Reference interval of pregnancy-associated plasma protein-A in healthy men and non-pregnant women
(ELSEVIER, 2013-01-01) Coskun, Abdurrahman; Serteser, Mustafa; Duran, Sadik; Inal, Tamer C.; Erdogan, Birsen E.; Ozpinar, Aysel; Can, Ozge; Unsal, Ibrahim
Objective: The serum pregnancy-associated plasma protein-A (PAPP-A) concentration is a predictor of ischemic cardiac events and renal impairment. However, the reference interval of PAPP-A has not been determined. This study determined the reference interval of PAPP-A in men and non-pregnant women. Methods: The study enrolled 126 apparently healthy individuals (52 males and 74 females). The mean age of the men and women was 34.7 (range 20-66) years and 34.6 (range 18-65) years, respectively. Serum PAPP-A concentrations were determined using an ultrasensitive enzyme-linked immunoassay kit. Reference intervals were calculated using the bootstrap method. Results: The results for three subjects were outliers, so the reference interval of PAPP-A was calculated using the data for 123 subjects. PAPP-A was undetectable in 26 subjects. The reference interval of PAPP-A for men and women (with the 90\% confidence interval) was <22.9 ng/mL (19.7-23.3) and <33.6 ng/mL (25.2-36.7), respectively. In male subjects, serum PAPP-A levels of smokers {[}3.10 (UD, 7.30) ng/mL] were significantly lower than that of non-smokers {[}11.00 (UD, 24.4) ng/mL] (p < 0.001) and there was a positive correlation between serum PAPP-A levels and subjects' age (r=0.439
Sequential filtering for clinically relevant variants as a method for clinical interpretation of whole exome sequencing findings in glioma
(BMC, 2021-01-01) Ulgen, Ege; Can, Ozge; Bilguvar, Kaya; Boylu, Cemaliye Akyerli; Yuksel, Sirin Kilicturgay; Danyeli, Ayca Ersen; Sezerman, O. Ugur; Yakicier, M. Cengiz; Pamir, M. Necmettin; Ozduman, Koray
Background In the clinical setting, workflows for analyzing individual genomics data should be both comprehensive and convenient for clinical interpretation. In an effort for comprehensiveness and practicality, we attempted to create a clinical individual whole exome sequencing (WES) analysis workflow, allowing identification of genomic alterations and presentation of neurooncologically-relevant findings. Methods The analysis workflow detects germline and somatic variants and presents: (1) germline variants, (2) somatic short variants, (3) tumor mutational burden (TMB), (4) microsatellite instability (MSI), (5) somatic copy number alterations (SCNA), (6) SCNA burden, (7) loss of heterozygosity, (8) genes with double-hit, (9) mutational signatures, and (10) pathway enrichment analyses. Using the workflow, 58 WES analyses from matched blood and tumor samples of 52 patients were analyzed: 47 primary and 11 recurrent diffuse gliomas. Results The median mean read depths were 199.88 for tumor and 110.955 for normal samples. For germline variants, a median of 22 (14-33) variants per patient was reported. There was a median of 6 (0-590) reported somatic short variants per tumor. A median of 19 (0-94) broad SCNAs and a median of 6 (0-12) gene-level SCNAs were reported per tumor. The gene with the most frequent somatic short variants was TP53 (41.38\%). The most frequent chromosome-/arm-level SCNA events were chr7 amplification, chr22q loss, and chr10 loss. TMB in primary gliomas were significantly lower than in recurrent tumors (p = 0.002). MSI incidence was low (6.9\%). Conclusions We demonstrate that WES can be practically and efficiently utilized for clinical analysis of individual brain tumors. The results display that NOTATES produces clinically relevant results in a concise but exhaustive manner.
Simple concentration method enables the use of gargle and mouthwash instead of nasopharyngeal swab sampling for the diagnosis of COVID-19 by PCR
(SPRINGER, 2021-01-01) Kocagoz, Tanil; Can, Ozge; Yurttutan Uyar, Neval; Aksoy, Ece; Polat, Tuba; Cankaya, Dilara; Karakus, Betul; Mozioglu, Erkan; Kocagoz, Sesin
Since its emergence in December 2019, SARS-CoV-2 is causing one of the most devastating pandemics in human history. Currently, the most important method for definitive diagnosis of COVID-19 is identification of SARS-CoV-2 RNA in nasopharyngeal swab samples by RT-PCR. Nasopharyngeal swab sampling is a discomforting procedure sometimes with adverse effects, which also poses a risk for infection for the personnel performing the sampling. We have developed a new method for concentrating biological samples, which enabled us to use gargle and mouthwash samples to be used in RT-PCR, for the diagnosis of COVID-19, as an alternative to nasopharyngeal swab samples. We have analyzed nasopharyngeal and gargle and mouthwash samples, before and after concentration, of 363 patients by RT-PCR for the presence of SARS-CoV-2. Among 114 patients in which SARS-CoV-2 was identified in at least one of their samples, the virus was identified in 76 (66.7\%), 67 (58.8\%), and 101 (88.6\%) of nasopharyngeal swab, gargle, and mouthwash samples before and after concentration, respectively. When concentrated by our new method, gargle and mouthwash samples can be used instead of nasopharyngeal samples in identification of SARS-CoV-2 by RT-PCR, with the same or better sensitivity. Eliminating the need for nasopharyngeal sampling will save the patients from an invasive and painful procedure and will lower the risk of infection for the healthcare personnel taking the sample. This easy sampling procedure may decrease the workload of hospitals, shorten the turnaround time of obtaining test results, and thus enable rapid isolation of infected patients.