İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
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Güncel Gönderiler
Determination of guaifenesin in spiked human breast milk: HPLC-UV method development, validation, and uncertainty evaluation
(Taras Shevchenko National University of Kyiv, 2025) Ceylan, Burhan; Önal, Cem; Önal, Armağan
A simple, sensitive, and reliable isocratic reversed-phase high-performance liquid chromatography (HPLC UV) method was developed, validated, and applied for the quantitative determination of guaifenesin in spiked human breast milk. Chromatographic separation was achieved on a C18 column (150 x 4.6 mm, 5 µm) using a mobile phase composed of methanol and water (50:50, v/v), where the aqueous phase was acidified with orthophosphoric acid (pH=3.2). The flow rate was 0.8 mL min-1, and detection was performed at 230 nm. The method exhibited excellent linearity over the concentration range of 5.0-30.0 ng mL-1 with a correlation coefficient of r2=0.9999. Liquid-liquid extraction (LLE) was used for sample preparation and resulted in a mean relative recovery of 98.82% with an absolute recovery of 99.52%, while effectively minimizing matrix interferences associated with breast milk. Method validation was performed in accordance with European Medicines Agency (EMA) bioanalytical guidelines, including assessments of selectivity, accuracy, precision, sensitivity, robustness, and stability. The method demonstrated strong reproducibility, did not require an internal standard, and provided a short analysis time suitable for routine application. This study presents the first simple, cost-effective, and sensitive HPLC-UV method for the determination of guaifenesin in human breast milk, offering a valuable analytical tool for evaluating drug safety during lactation.
The impact of conventional chemotherapy regimens and targeted drugs on ovarian function in breast cancer patients
(Springer Nature Link, 2026) Hasköylü, Şeyma; Şahin, Şevval Berfin; Altıntaş, Alara; Yıldız, Şule; Bildik, Gamze; Benlioğlu, Can; Turan, Volkan; Kim, Samuel; Öktem, Özgür
Breast cancer is the most common malignancy among women, affecting nearly 1.5 million individuals worldwide every year. While survival rates improve, many reproductive-age survivors confront significant long-term consequences, particu larly diminished ovarian reserve, infertility, and premature ovarian insufficiency due to the gonadotoxic effects of chemo therapy. Postponement of pregnancy for five years or more after treatment exacerbates the decline in fertility due to ongo ing ovarian aging and depletion of residual ovarian reserve. Women carrying BRCA1/2 mutations may already exhibit reduced ovarian reserve and are more vulnerable to gonadal damage, possibly due to impaired DNA repair mechanisms associated with these mutations. The contribution of other breast cancer susceptibility genes (e.g., ATM, CHEK2, PALB2, BARD1, RAD51C, RAD51D, and TP53) to chemotherapy-induced gonadotoxicity remains unclear. Although animal data shows depletion of primordial follicle pool and granulosa cells dysfunction, the ovarian effects of the poly(ADP-ribose) polymerase (PARP) inhibitors in women with and without BRCA mutation are not clear. Immune-check point inhibi tors (ICIs) causes immune-mediated destruction of the primordial follicle pool and reduction in ovarian reserve. Cyclin dependent kinase inhibitors appear to be less toxic than ICIs. In this narrative review of the current literature we aimed to provide a comprehensive overview of the molecular mechanisms underlying ovarian toxicity associated with conventional chemotherapy and targeted therapies in breast cancer treatment.
From awareness to action: Do the food safety attitudes affect sustainable food consumption behaviors in university students?
(Frontiers Media S. A., 2026) Pınarlı Falakacılar, Çağla; Bilginer Diler, Gamzegül; Terzi, Merve
Background: Ensuring food safety and promoting sustainable food consump tion are increasingly important public health priorities, especially among young adults who are forming long-term dietary habits. This study explored how univer sity students’ food safety attitudes relate to their sustainable food consumption behaviors. Methods: This cross-sectional study was conducted with 360 university students between May and September 2024. Validated scales were used to measure food safety attitudes (FSAS) and sustainable food consumption behaviors (SFCBS). Additional data collected included gender and body mass index (BMI). Statistical analyses evaluated differences between groups and correlations among key variables. Results: The findings showed that 83.3% of participants had adequate food safety attitudes. Female students scored significantly higher than males on both the food safety attitude and SFCBS scales, including subdimensions such as caring, assimilating, and shopping/cooking habits (p < 0.05). A moderate positive corre lation was identified between FSAS and SFCBS, particularly for general nutritional behaviors (r = 0.446, p < 0.05). Additionally, positive correlations were found between SFCBS and FSAS subdimensions. Conclusion: Overall, the results indicate that female students exhibit stronger food safety attitudes and sustainable food consumption behaviors, and that fos tering awareness of these practices during university years may contribute to healthier, more environmentally responsible lifestyles in line with global sustain ability goals.
Post-vaccination SARS-CoV-2 infections and antibody responses after BNT162b2 in patients with severe obesity: A retrospective cohort study
(Frontiers Media S. A., 2026) Kara, Zehra; Ak, Tümay; Demir, Ahmet Numan; Akçin, Rüveyda; Dinç, Harika Öykü; Taşkın, Halit Eren; Gareayaghi, Nesrin; Kocazeybek, Bekir; Yumuk, Volkan Demirhan
Aim: The aim of this study was to describe the frequency of post-vaccination SARS-CoV-2 infection and to compare SARS-CoV-2 IgG antibody levels between patients with severe obesity and individuals without obesity after two doses of the BNT162b2 vaccine. Methods: One hundred two consecutive patients with severe obesity seen in the obesity outpatient clinic and 54 individuals without obesity who visited a vaccination outpatient clinic were included in the study. Inactivated Severe Adult Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) IgG levels of these two groups were measured four weeks after administration of two doses of BNT162b2 vaccine. SARS-CoV-2 infection was defined as a PCR-confirmed infection documented in hospital records during the 12-month follow-up after completion of two-dose BNT162b2 vaccination. PCR testing was performed only when participants presented to the hospital with clinical suspicion of COVID-19 and was not conducted as routine screening. Clinical characteristics, protective measures and contact history were also queried. Results: There was a statistically significant difference in SARS-CoV-2 infection rates after vaccination between the patients with severe obesity (n=28, 27%) and individuals without obesity (n=3, 5%) (p=0.001). In patients with severe obesity, SARS-CoV-2 IgG levels after BNT162b2 vaccination were lower in the group with SARS-CoV-2 infection than in the group without SARS-CoV-2 infection [2697 (1096-8955); 8103 (2208-26903) AUml, respectively] (p=0.008). The antibody levels of those with severe fatigue were lower than those without these complaints [2440 (365-4447); 8955 (2440-16317) AUml, respectively] (p=0.03). A loss of taste or smell was observed in 75% of patients with severe obesity but was not observed in individuals without obesity (p=0.03). In patients with severe obesity, those with taste/smell loss had statistically significantly lower SARS CoV-2 IgG titres than those without severe obesity [2568 (400-4830); 95(2611-16810) AUml, p: 0.02]. Multiple logistic regression analysis revealed a correlation between body mass index (BMI) and having had a SARS-CoV-2 infection after BNT162b2 vaccination (p = 0.028, Exp(B) = 1.072). There was no need for hospitalisation due to SARS-CoV-2 infection and there were no deaths in either group. Conclusion: Patients with severe obesity had higher rates of SARS-CoV-2 infection after BNT162b2 vaccination compared to individuals without obesity. SARS-CoV-2 IgG levels were lower in patients with severe obesity after BNT162b2 vaccination. Based on these findings, given the higher frequency of post-vaccination infections in the patients with severe obesity, timely booster vaccination policies may be particularly important for this population.Severe obesity, SARS-CoV-2, BNT162b2, SARS-CoV-2 IgG, breakthrough infection. Key points: The rate of SARS-CoV-2 infection after vaccination was higher in patients with severe obesity than in individuals without obesity.It has been found that antibody levels are lower in patients with severe fatigue symptoms than in patients without these symptoms.Loss of taste or smell was observed at a high rate (75%) in the group with severe obesity, but not in individuals without obesity.In this study, there were no hospitalisations or deaths after vaccination with BNT162b2 in patients with severe obesity.Body mass index (BMI) has been found to negatively affect the likelihood of contracting SARS-CoV-2 infection after receiving the BNT162b2 vaccine.In our study, we emphasise the importance of vaccination in patients with severe obesity.
An update on fertility preservation from the asian society for fertility preservation
(Wiley, 2026) Turan, Volkan; Faizal Bin Ahmad, Mohd; Di, Wen; Gook, Debra; Kaul, Nalini; Kim, Seok Hyun; Ko, Jennifer; Chau Le, Thi Minh; Lee, Jung Ryeol; Öktem, Özgür
Fertility preservation (FP) is a rapidly expanding field in reproductive medicine with still limited data on outcomes. FP aims to protect the fertility of children, women, and men who face the potential risk of fertility loss for various medical conditions, including but not limited to cancer and its gonadotoxic treatment forms. Therefore, it is crucial to provide evidence-based recommendations to assist health professionals in discussing FP options. Our aim was to provide a guideline for multidiscipli nary medical staff in considering the availability of FP options and to help them decide whether to provide FP. The objective of any FP intervention is to minimize or eliminate primary disease burden and to ensure the maintenance or preserving reproductive health. Therefore, people who are at risk of losing fertility should be evaluated for and counseled about future reproductive risks. Embryo, oocyte, and ovarian tissue cryopreservation are the established FP options in adult females, with ovarian tissue cryopreservation the only option for prepubertal girls. A wide range of variables affect the choice of the FP strategy. These include age and ovarian reserve of women, the time available before the initiation of cancer treatment, puber tal status, and cancer type and stage. In males, sperm cryopreservation is a highly effective method in adolescent and adult males, while testicular tissue cryopreservation, which is experimental, is the only available option for prepubertal males. This review addressed the important clinical questions and provided answers for FP in females, males, and children according to the indications and availability of FP.
