İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
DSpace@İSTÜN, Üniversite mensupları tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Development and validation of an HPLC method for quantification of solifenacin in spiked human breast milk
(Korean Society of Analytical Sciences, 2025) Ceylan, Burhan; Çayci, Meltem; Önal, Cem; Önal, Armağan
An efficient and reliable reversed phase high performance liquid chromatography (HPLC) method was established and validated for the quantitative analysis of solifenacin succinate in fortified human breast milk samples. Chromatographic separation was carried out on a C18 column (150 × 4.6 mm, 5 μm particle size) and a isocratic mobile phase composed of acetonitrile and phosphate buffer (pH 3.5) in a 65:35 (v/v) ratio. The flow rate was at 1.1 mL/min, and detection was performed at 225 nm using a ultraviolet (UV) detector. The method exhibited excellent linearity in the range of 1.0 to 40.0 ng/mL (r² = 0.9999). The validation process was performed in accordance with European Medicines Agency (EMA) bioanalytical guidelines, and included selectivity, accuracy, precision, sensitivity, recovery, robustness, and stability assessments. The liquid-liquid extraction (LLE) procedure used for sample pretreatment provided satisfactory recovery (mean: 99.32 %) and minimized matrix interferences from breast milk. The method showed high reproducibility, did not require an internal standar, and offered a rapid analysis time of approximately 3.4 minutes. This study offers a simple, cost-effective, and sensitive HPLC-UV method for monitoring solifenacin levels in breast milk matrices, providing a valuable tool for evaluating drug safety during lactation.
Exploring cervical vestibular evoked myogenic potential responses to different stimuli at different frequencies
(Karger, 2025) Karababa, Ercan; Özdemir Aktaş, Betül; Akın Öcal, F. Ceyda; Satar, Bülent
Objetive: This study aimed to compare cervical vestibular evoked myogenic potentials (cVEMP) elicited by Tone Burst (TB) and Narrow Band Level-Specific Chirp (NB LS-CE Chirp) stimuli at 500, 1000, 2000, and 4000 Hz in healthy individuals. Methods: Thirty-two healthy participants (15 females, 17 males; mean age: 24.59 ± 1.93 years) underwent otoscopic examination, pure-tone audiometry, and cVEMP testing at 95 dB nHL using TB and NB LS-CE Chirp stimuli. P1 latency, N1 latency, and P1N1 amplitude were recorded. Results: At 500 Hz, both stimuli elicited responses in all subjects. Significant differences in P1 latency, N1 latency, and P1N1 amplitude were found between the stimuli at 500 and 1000 Hz (p <0.05). No significant differences were observed at 2000 and 4000 Hz (p> 0.05). Conclusion: NB LS-CE Chirp stimuli generate larger and earlier cVEMP responses than TB stimuli, particularly at lower frequencies, suggesting higher effectiveness for saccular assessment.
Ultrasound-assisted sustainable processing of garden cress juice: Enhancing bioactive compounds and bioaccessibility through xgboost optimization
(American Chemical Society, 2025) Levent, Okan; Şimşek, Mehmet Ali; Yıkmış, Seydi; Demirel, Selinay; Tokatlı Demirok, Nazan; Türkol, Melikenur; Aljobair, Moneera; Tokatlı, Nazlı; Mohamed Ahmed, Isam A.
This study aimed to improve the functional and nutritional properties of garden cress (Lepidium sativum) juice using ultrasound and optimize process parameters by modeling them with advanced machine learning algorithms. Using a Box−Behnken experimental design, the effects of sonication time (8−16 min) and amplitude (60−100%) on total chlorophyll, total phenolic content (TPC), and ferric reducing antioxidant power (FRAP) were investigated. Nonparametric, high-accuracy estimations were made using the XGBoost algorithm. Optimum conditions were determined to be 12 min and 80% amplitude. Under these conditions, TPC (78.44 mg GAE/mL), FRAP (59.80 mg TE/mL), and chlorophyll (7.15 g/100 mL) values were significantly higher than those in control and pasteurized samples (p < 0.05). HPLC-DAD analysis showed that ultrasound treatment positively impacted the phenolic profile by increasing the release of quercetin, quercetin derivatives, caffeic acid, and chrysin. GC-MS data revealed that volatile aroma compounds (especially 1-hexanol, benzaldehyde, and cinnamaldehyde) were preserved mainly by ultrasound. In vitro digestion simulation showed that total postdigestion recovery rates in ultrasound-treated samples were 34.96% for TPC, 32.50% for chlorophyll, and 28.81% for FRAP, demonstrating a significant increase in bioaccessibility. PCA and hierarchical clustering analyses confirmed a significant biochemical separation of ultrasound-treated samples. The findings indicate that ultrasound technology is a superior method for preserving bioactive compounds, maintaining the aroma profile, and enhancing bioaccessibility compared to heat treatment. This enables data-driven process design. The developed model showed a strong predictive performance under optimal conditions. However, the study is limited by the relatively small data set used for model training.
Comparison of short- and long-term outcomes of diode laser vs. crystallized phenol treatment for pilonidal sinus disease: A propensity score-matched multicentre study
(Wiley, 2025) Bilgin, İsmail Ahmet; Ramoğlu, Nur; Saylık, Onur; Benlice, Çigdem; Erkaya, Metincan; Kurtul, İnci; Aghayeva, Afag; Turan, Ersin; Maden, Abdullah Sami; Acar, Fahrettin; Karahasanoğlu, Tayfun; Hamzaoğlu, İsmail; Baca, Bilgi; Doğru, Osman
Aim: Pilonidal sinus disease (PSD) primarily affects young adults; rapid recovery is essential and yet lacks a standardized treatment approach. While excisional techniques delay recovery, minimally invasive options like laser ablation and phenol application are gaining interest, yet comparative long-term evidence is scarce. This study compared short- and long-term outcomes of laser versus phenol treatment in PSD. Method: In this multicentre retrospective cohort study (Nov. 2017–Sep. 2024), patients treated with laser or phenol were included. 1:3 propensity score matching using the nearest neighbour algorithm was performed based on age, gender, prior surgical history and year of operation. Categorical variables were analysed using chi-squared or Fisher's exact tests, whereas continuous variables were compared using Student's t-test or Mann– Whitney U test depending on distribution normality. Results: Out of 897 eligible patients, 644 were included (median age: 26 years, body mass index [BMI]: 26.2 kg/m2 , male-to-female ratio: 4:1). The number of sinuses/pits was 2–3 in both groups. Operating time was significantly longer in the laser group. Complications occurred in 6.8% of laser patients, whereas none were reported in the phenol group. Pain scores were higher in the laser group (2 [1–3] vs. 1 [0–2]). Median follow-up was 45 months (laser) and 40 months (phenol). Return to daily activities was delayed in the laser group, whereas complete healing was slower in the phenol group. Readmission, recurrence and recovery rates were comparable (85%–86%). Conclusion: Both treatments demonstrated low complication and recurrence rates with high recovery rates. Laser favoured faster healing and fewer sessions, whereas phenol allowed for shorter procedures and earlier return to daily life.
Investigation of the effects of melatonin on granulosa cell proliferation and DNA methylation
(Proceedings of the Bulgarian Academy of Sciences, 2025) Türkmen, Ervanur; Gündoğan, Gül İpek; Arslan, Halil İbrahim; Gök Yurttaş, Asiye; Elgün, Tuğba
Melatonin, a pineal hormone with antioxidant and regulatory functions, has emerged as a key modulator of ovarian physiology. Its presence in fol licular fluid suggests important roles in granulosa cell function, follicle devel opment, and reproductive outcomes. However, its effects on granulosa cell tumour (GCT) biology and epigenetic regulation remain insufficiently defined. This study aimed to investigate the effects of melatonin on proliferation and global DNA methylation in human granulosa tumour cells (COV434) com pared with healthy endothelial controls (HUVECs). COV434 and HUVEC cells were treated with melatonin at 1, 10, 100, and 1000 µM. Cell viabil ity and proliferation were assessed using the MTT [3-(4.5-dimethylthiazol-2- yl)-diphenyl tetrazolium bromide] (Cambridge, UK) assay and xCELLigence RTCA system (Roche), while DNA methylation was quantified with a 5-mC ELISA kit (Epigentek Group Inc, USA). Experimental groups included nega tive, sham, melatonin-treated, and positive controls. Melatonin showed a cell type-dependent effect. In COV434 cells, proliferation was significantly inhib ited, with an IC50 of 10.55 µM, whereas HUVECs displayed increased prolifer ation at higher doses. DNA methylation levels decreased in both cell types in a dose-dependent manner, reaching the highest significance in COV434 cells at 1000 µM (p < 0.001). In conclusion, melatonin demonstrated a dose-dependent inhibitory effect on COV434 cell proliferation while simultaneously reducing global DNA methylation levels.
