Browsing by Author "Beksac, Mehmet Sinan"

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Analysis of 3-hydroxyisovaleric acid and 3-hydroxybutyric acid in plasma samples by LC-MS/MS
(2022) Recber, Tuba; Ozkan, Ece; Nemutlu, Emirhan; Beksac, Mehmet Sinan; Kir, Sedef
Down syndrome is a common genetic disorder that results from the presence of an extra chromosome in the 21st chromosome pair of humans. Metabolomics is an alternative method in discovery of new biomarkers for the screening and diagnosis of Down syndrome. In this study, quantitative analyzes of 3-hydroxybutyric acid and 3hydroxyisovaleric acid, selected as possible markers for prenatal diagnosis of Down syndrome were performed. LCMS/MS analyzes were performed on a Phenomenex Luna NH2(100 x 4.6 mm, 3 mu m) column using a mobile phase mixture of 0.1% formic acid and acetonitrile containing 0.1% formic acid at a flow rate of 0.35 mL/minute. The MRM transitions were 103.0 -> 59.0 for 3-hydroxybutyric acid and 117.1 -> 59.0 for 3-hydroxyisovaleric acid. Under these conditions, the retention times of 3-hydroxyisovaleric acid 3-hydroxybutyric acid were 2.7 and 3.1 minute, respectively. The method was found linear from 0.1 to 10.0 mu g/mL for both metabolites. The limit of detection (LOD) was 0.017 mu g/mL for 3-hydroxybutyric acid and 0.003 mu g/mL for 3-hydroxyisovaleric acid. The lower limit quantification (LLOQ) was 0.045 mu g/mL for 3-hydroxybutyric acid and 0.008 mu g/mL for 3-hydroxyisovaleric acid. The method has been proven to be selective, precise, accurate, sensitive, and robust based on the validation studies results. Finally, the method was applied to plasma samples of the pregnant women with healthy fetus (n = 30) and with Down syndrome fetus (n = 17). As a result of the analysis, a statistically significant increase (p <0.01) was observed in the 3-hydroxybutyric acid level of the group with Down syndrome compared to the healthy group. This result strengthens the use of 3-hydroxybutyric acid as an important biomarker in the prenatal screening/diagnosis of Down syndrome.
Budget impact of incorporating non-invasive prenatal testing in prenatal screening for Down syndrome in Turkey
(2019) Okem, Zeynep Guldem; Orgul, Gokcen; Kasnakoglu, Berna Tari; Cakar, Mehmet; Beksac, Mehmet Sinan
Objectives: To provide information to the government about the budget impact of implementing non-invasive prenatal testing (NIPT) into prenatal screening strategies to detect Down syndrome (DS) in singleton pregnancies in Turkey; the likely costs or savings associated with NIPT in comparison to the current practice were calculated. Methods: A decision-analytic model was developed to calculate the cost estimates for 1,309,771 women who gave birth in 2016; 84.8% of whom were <35-years-of-age. The superior combined test (CT) among current strategies is compared with contingent NIPT for women <35-years-of-age; and usual practice of amniocentesis (AC) for women >= 35 years-of-age was replaced with universal NIPT. Results: When the market price of NIPT (1,077 PPPUS$) is used, contingent NIPT offered to high-risk women <35-years-of-age adds 34,907,225 PPPUS$; and for women-35 >= years-of-age the universal NIPT leads to 142,785,818 PPPUS$ more cost to the government compared to current strategies. The additional costs with NIPT are partially compensated by the cost-savings due to reduction of the number of invasive tests and procedure related losses (17,826,476 PPPUS$ for women <35-years-of-age and 37,070 PPPUS$ for women >= 35-years-of-age). Results are sensitive to the NIPT costs; with a lower cost of NIPT, a total saving would be 33,116,046 PPPUS$ with new strategies. Conclusions: NIPT might be the choice of prenatal screening strategies if its price is lowered to economically acceptable levels. Until that time, currently accepted protocols seem to be more realistic. On the other hand, decision makers should also consider possible savings and the women's quality of life that can be improved with the new technology. (C) 2019 Fellowship of Postgraduate Medicine. Published by Elsevier Ltd. All rights reserved.
Concerns of Pregnant Women in "Prenatal Screening/Diagnosis" Practice and Termination of Pregnancy
(2020) Kasnakoglu, Berna Tari; Cakar, Mehmet; Okem, Zeynep Guldem; Tanacan, Atakan; Fadiloglu, Erdem; Orgul, Gokcen; Beksac, Mehmet Sinan; 32157675
Objective To investigate the reasons for decision-making and concerns of patients in the field of prenatal screening, invasive prenatal diagnostic testing (IPDT), and termination of pregnancy (TOP). Study Design This questionnaire-based study consisted of 107 pregnant women who were referred for prenatal screening to the Hacettepe University Hospital. The questionnaire given to patients was prepared from scratch since there is no standard set of questions measuring patients' feelings and concerns regarding prenatal screening/diagnosis, IPDT, and TOP. Results Our questionnaire results showed that it is possible to classify decision-making factors into 6 groups: psychological, social, fear, religious/ faith, support, and trust. The majority of patients were undecided (48.6 %) about IPDT if prenatal screening test results were risky. Only 23.4 % of patients were willing to accept IPDT. On the other hand, 55.1 % of patients were not willing to undergo TOP if the fetal karyotyping results were abnormal. Religious factors seem to be important in refusing IPDT and TOP. Conclusion Physicians should re-evaluate their practice in the field of prenatal screening and diagnosis in light of the high refusal rates of IPDT and TOP. Understanding factors influencing women's decision-making processes provides insight for service providers to help women at high risk of having foetal anomalies to make better-informed choices.