Özgür Tosun

Dr. Özgür Tosun

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 January 2022 in Mathematics
Verified
Journal Article
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MYMeliz Yuvalı
Meliz Yuvalı
BYBelma Yaman
Belma Yaman
ÖTÖzgür Tosun
Özgür Tosun
In the last few decades, statistical methods and machine learning (ML) algorithms have become efficient in medical decision-making. Coronary artery disease (CAD) is a common type of cardiovascular disease that causes many deaths each year. In this study, two CAD datasets from different countries (TRNC and Iran) are tested to understand the classification efficiency of different supervised machine learning algorithms. The Z-Alizadeh Sani dataset contained 303 individuals (216 patient, 87 control), while the Near East University (NEU) Hospital dataset contained 475 individuals (305 patients, 170 control). This study was conducted in three stages: (1) Each dataset, as well as their merged version, was subject to review separately with a random sampling method to obtain train-test subsets. (2) The NEU Hospital dataset was assigned as the training data, while the Z-Alizadeh Sani dataset was the test data. (3) The Z-Alizadeh Sani dataset was assigned as the training data, while the NEU hospital dataset was the test data. Among all ML algorithms, the Random Forest showed successful results for its classification performance at each stage. The least successful ML method was kNN which underperformed at all pitches. Other methods, including logistic regression, have varying classification performances at every step.

30 March 2023 in Journal of Clinical Medicine
Verified
Journal Article
Open access
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ABAYSEGUL BOSTANCI
AYSEGUL BOSTANCI
UGUmut Gazi
Umut Gazi
ÖTÖzgür Tosun
Özgür Tosun
KSKaya Süer
Kaya Süer
EEEmine Unal Evren
Emine Unal Evren
TSTamer Sanlidag
Tamer Sanlidag
A substantial proportion of coronavirus disease 2019 (COVID-19) survivors continue to suffer from long-COVID-19 (LC) symptoms. Our study aimed to determine the risk factors for LC by using a patient population from Northern Cyprus. Subjects who were diagnosed with severe acute respiratory syndrome-2 (SARS-CoV-2) infection in our university hospital were invited and asked to fill in an online questionnaire. Data from 296 survivors who had recovered from COVID-19 infection at least 28 days prior the study was used in the statistical analysis. For determination of risk factors for “ongoing symptomatic COVID-19 (OSC)” and “Post-COVID-19 (PSC)” syndromes, the patient population was further divided into group 1 (Gr1) and group 2 (Gr2), that included survivors who were diagnosed with COVID-19 within 4-12 weeks and at least three months prior the study, respectively. The number of people with post-vaccination SARS-CoV-2 infection was 266 (89.9%). B.1.617.2 (Delta) (41.9%) was the most common SARS-CoV-2 variant responsible for the infections, followed by BA.1 (Omicron) (34.8%), B.1.1.7 (Alpha) (15.5%), and wild-type SARS-CoV-2 (7.8%). One-hundred-and-nineteen volunteers (40.2%) stated an increased frequency of COVID-19-related symptoms and experienced the symptoms in the week prior to the study. Of those, 81 (38.8%) and 38 (43.7%) were from Gr1 and Gr2 groups, respectively. Female gender, chronic illness, and symptomatic status at PCR testing were identified as risk factors for developing OSC syndrome, while only the latter showed a similar association with PSC symptoms. Our results also suggested that ongoing and persistent COVID-19-related symptoms are not influenced by the initial viral cycle threshold (Ct) values of the SARS-CoV-2, SARS-CoV-2 variant as well as vaccination status and type prior to COVID-19. Therefore, strategies other than vaccination are needed to combat the long-term effect of COVID-19, especially after symptomatic SARS-CoV-2 infection, and their possible economic burden on healthcare settings.

1 January 2020 in International Journal of Chronic Obstructive Pulmonary Disease
Verified
Journal Article
Open access
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HCHuseyin Cagsin
Huseyin Cagsin
AUAli Uzan
Ali Uzan
ÖTÖzgür Tosun
Özgür Tosun
FRFinn Rasmussen
Finn Rasmussen
NSNedime Serakinci
Nedime Serakinci
Purpose: Telomere biology, especially tissue-specific ultra-short telomeres, might provide a strong contribution to our current knowledge in COPD development as well as a predictive marker for prognosis. To test this hypothesis, we investigated telomere lengths in lung tissue and leukocytes in patients diagnosed with COPD. Patients and Methods: Thirty-two patients were included in the current study. All patients showed a post-bronchodilator ratio of less than 70% post-bronchodilator predicted value of forced expiratory volume in second (FEV1%), mean 56%; range [19% to 86%]. To be able to investigate ultra-short telomeres, universal single telomere length analysis (U-STELA) was used. Results: Our results showed a higher level of the ultra-short telomere presence in bronchoalveolar lavage (BAL) cells when compared to leukocytes with statistical significance t(62)=5.771, p<0.00001. The FEV1% was lower in subjects with ultra-short telomeres in BAL (50.6% vs 81.6%: p<0.001) and in ultra-short telomeres in blood leukocytes (37.3% vs 58.5%: p=0.051) when compared to subjects without ultra-short telomeres in leukocytes. Furthermore, the patients who had ultra-short telomeres in BAL samples were significantly older (p=0.014) than patients who did not have ultra-short telomeres. Ultra-short telomeres in BAL (p=0.05) but not in leukocytes (p=0.33) were associated with FEV1% in a regressions model adjusting for age (p<0.0001), ever smoking (p<0.0001) and sex (p=0.71). The patients with ultra-short telomeres were graded higher in the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification (p=0.006). Conclusion: This study emphasizes the need to investigate the correct tissue to get a representative evaluation of the stage or advancedness of COPD. To our knowledge, this is the first study to show that there is a correlation between the presence of ultra-short telomeres in lung tissue and COPD severity. Our results suggest that ultra-short telomeres are involved in the molecular pathogenesis of COPD and might be used as a tissue-specific predictive biomarker.

7 March 2023 in Medicina
Verified
Journal Article
Open access
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DODila Ozyilkan
Dila Ozyilkan
ÖTÖzgür Tosun
Özgür Tosun
AİAYLİN İSLAM
AYLİN İSLAM
Background and Objectives: Today, oral diseases are well-known for their effects, not only on daily life but also on quality of life (QoL). Dental caries, especially early childhood caries (ECC), are considered a public health concern as regards their impact on the life quality of children and parents from multiple aspects. The present research was conducted to assess the effect of anemia on oral-health-related quality of life (OHRQoL) in terms of children and parents. Materials and Methods: The current study was performed in two independent stages. In the first stage, the Turkish version of the Early Childhood Oral Health Impact Scale (ECOHIS), and in the second stage, the Turkish version of the Parental-Caregivers Perceptions Questionnaire (P-CPQ) were used to measure the effect of anemia-related dental caries among children and parents. SPSS and Jamovi software were used for all calculations, graphs and comparisons. Results: A total of 204 participants (child–parent pairs) were incorporated in the present study. A considerable number of children (81.5%) reported occasional or more frequent oral/dental pain. Secondly, the subscale scores were determined for child symptoms (2.25 ± 0.067), child function (6.8 ± 0.22), child psychology (3.87 ± 0.128), self-image and social interaction (1.74 ± 0.063), parental distress (3.82 ± 0.143), and family function (3.5 ± 0.121). Additionally, more than half of the parents (56.3%) responded “fair” for the health of their children’s teeth, lips, jaws and mouth. Similarly, the child’s overall well-being was stated as being affected “a lot” by the condition of their child’s teeth, lips, jaws or mouth by half of the parents (49.5%). Conclusions: Anemia-related dental caries has a highly negative impact on the quality of life of children and parents according to both of the questionnaires. Therefore, children with high scores should be prioritized for preventive procedures and timely dental treatments.

1 January 2005 in Endocrine Research
Verified
Journal Article
Closed access
MCMehtap Cakir
Mehtap Cakir
RSRAMAZAN SARI
RAMAZAN SARI
ÖTÖzgür Tosun
Özgür Tosun
UKUmit Karayalcin
Umit Karayalcin
The objective of this study was to investigate the serum leptin response to oral glucose stimulation in a group of obese and nonobese normotensive, normolipidemic, and glucose-tolerant premenopausal women. Twenty-one obese (BMI: 37.7 ± 6.3 kg/m2) and 14 nonbese (BMI: 21.5 ± 1.0 kg/m2) age-matched, healthy premenopausal women were included in the study. Serum glucose, insulin, and leptin levels were measured at 30 min intervals during the 120 min of an oral glucose tolerance test (OGTT). Mean serum glucose, insulin, and leptin levels were significantly higher in the obese group compared to nonobese subjects during OGTT. Except for a 120 min decrement noted in obese women, no changes occurred in serum leptin levels during oral glucose stimulation in both groups. As a conclusion, absence of a significant elevation in serum leptin levels during OGTT in our obese subjects compared to nonobese subjects may be related to their normal metabolic variables despite being abdominally obese and insulin resistant.