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
Nicotinic acid–modified chitosan nanoparticles for enhanced resveratrol delivery and anticancer activity
(Wiley, 2026) Şentürk, Sema; Kaplan, Özlem; Bal, Kevser; Küçükertuğrul Çelik, Sibel; Gökşen Tosun, Nazan; Gök, Mehmet Koray
This study focused on functionalizing chitosan with nicotinic acid, the active form of vitamin B3, to obtain a new derivative (ChiNico) with enhanced solubility at physiological pH, improved proton buffering capacity, and in vitro anticancer activity, and to develop resveratrol-loaded nanoparticles (nChiNico-RES) for enhanced anticancer performance. Chitosan was modified through EDC-mediated amidation, and successful conjugation was confirmed by FTIR, 1H NMR, and GPC/SEC analyses. Nicotinic acid grafting increased molecular weight, introduced characteristic amide signals, improved solubility at physiological pH, and enhanced proton buffering capacity. Nanoparticles were prepared by ionotropic gelation and showed sizes of 100–140nm, PDI values below 0.4, and a positive surface charge of +18 to +20mV. Blank nanoparticles exhibited minimal cytotoxicity, while resveratrol-loaded formulations demonstrated significant anticancer activity in HeLa cervical cancer cells and HT-29 human colon adenocarcinoma cell line. Notably, nChiNico-RES reduced HeLa and HT-29 cell viability more effectively than free resver atrol and nanoparticles based on unmodified chitosan, indicating an additive contribution from nicotinic acid. In contrast, the cytotoxic effect on healthy BJ fibroblasts remained considerably lower, supporting the biocompatibility and selective potential of the system. Overall, nicotinic acid modification improves chitosan's carrier performance and offers a novel strategy by combin ing two natural bioactive molecules within a single nanoparticle platform.
The letrozole use in reproductive medicine: Beyond aromatase inhibition - a comprehensive review
(Galenos Publishing House, 2026) Aydın, Gerçek; Hatırnaz, Şafak; Hatırnaz, Ebru Saynur; Çetinkaya, Mehmet Bilge; Akdeniz, Muhterem; Dokuzeylül Güngör, Nur; Güler, Oğuz; Merdanoğlu, Merdan Ali; Uzun, Asiye; Eroğlu, Semra; Dahan, Michael
Letrozole and other aromatase inhibitors are increasingly recognized as first-line ovulation induction (OI) medications, offering an efficient and physiologic approach to ovarian stimulation that enhances outcomes in reproductive medicine. By selectively inhibiting aromatase and maintaining lower peripheral estrogen levels, letrozole supports mono- or bi-follicular development while reducing the risk of supraphysiologic estradiol exposure seen with traditional gonadotropin regimens. These pharmacological characteristics have contributed to its expanding use not only in OI but also in various assisted reproductive technologies. To evaluate the clinical benefits, effectiveness, and safety of using letrozole in in vitro fertilization (IVF), in vitro maturation (IVM), and OI, with particular attention to reproductive outcomes, ovarian response, endometrial effects, cycle characteristics, and treatment-related adverse events. A comprehensive systematic search covering the period from December 2000 to November 2025 was conducted across major electronic databases including PubMed, Embase, the Cochrane Library, and Google Scholar. The search strategy incorporated predefined keywords related to letrozole, aromatase inhibition, OI, IVF, and IVM. Studies involving randomized controlled trials, observational cohorts, and meta analyses were included, while non-clinical and non-reproductive data were excluded. Relevant outcomes were extracted and synthesized qualitatively. Letrozole demonstrates broad clinical utility in reproductive medicine, spanning assisted reproductive techniques, ovarian stimulation strategies, and the management of ovarian hyperstimulation syndrome risk, ectopic pregnancy, and endometriosis-related infertility. Its targeted estrogen suppression, cost-effectiveness, and favorable safety profile make it a valuable component of individualized treatment protocols. Nonetheless, further high-quality research is required to refine optimal dosing strategies, identify ideal patient populations, and clarify long-term reproductive and obstetric safety.
Survey on the usage and frequency of digital magnification devices in dentistry
(BioMed Central, 2026) Kıtın, Emine; Yazıcıoğlu, Oktay; Pekgöz, Abdullah; Kuzucan, Sera Gülhan
Objective This study aimed to evaluate the awareness, usage frequency, and perceptions of dental magnification devices (DMDs) among academic dental practitioners. Methods A cross-sectional survey was conducted at the Istanbul University Faculty of Dentistry, which targeted academic staff, doctoral candidates, and specialization students. A total of 159 participants completed an 18-item multiple-choice questionnaire. The data were collected via email and QR codes and statistically analyzed via descriptive and inferential methods. Results The results revealed increasing awareness and usage of DMDs, with ergonomic benefits and improved treatment precision being the most commonly cited advantages. Despite these benefits, barriers such as cost and concerns over device dependency have limited broader adoption. The participants indicated that magnification was particularly valuable in endodontics and restorative procedures. Conclusion The findings emphasize the growing recognition of DMDs in academic dental practice and highlight the need to incorporate magnification training into dental education curricula to enhance clinical skills and ergonomic awareness from an early stage.
Ozone treatment attenuates neuroinflammation and alters miRNA expression in a rat model of post-traumatic epilepsy
(Springer Nature Link, 2026) Demir, Hüseyin; Demirtaş, Cumaali; Yıldırım, Hava; Demir, Ecem; Kıroğlu Uzun, Sezin; Şevgin, Kübra; Beyaztaş, Hakan; Güler, Eray Metin; Hekimoğlu, Gulam; Çoşkunpınar, Ender Mehmet; Şanlıer, Nafiye; Yıldırım, Mehmet
The aim of this study was to investigate the effects of intraperitoneal ozone therapy in a post-traumatic epilepsy (PTE) model. An in vivo PTE model was established in male Sprague–Dawley rats, which were randomised to control (n=8), PTE (n=10), and PTE+Ozone (n=10) groups. 0.7 mg/kg ozone was administered intraperitoneally for 3 consecutive days. Seizure activity was video recorded for 120 min and evaluated for latency, frequency, duration, and severity. Behav ioral assessments of locomotor activity, anxiety, and spatial memory were conducted using open field, elevated plus, and radial arm maze tests on days 4–6 after the first ozone application. Blood and brain tissues were collected for biochemical assays (SUR1, TRPM4, IL-1β, IL-6, TNF-α, TAS, TOS, OSI, thiol–disulfide homeostasis), histological analyses (H&E, Cresyl Violet, and 8-OHdG immunostaining), and qRT-PCR of epilepsy-related miRNAs. Significant differences were observed among the groups for all serum and brain biomarkers (p<0.001). The PTE group showed marked increases in SUR1, TRPM4, IL-1β, IL-6, TNF-α, TOS, OSI, TT, NT, and DIS levels, accompanied by a decrease in TAS. Ozone treatment partially reversed these changes by reducing cytokine and oxidative stress markers, improving thiol–disulfide balance, and restoring TAS levels. Behavioural testing revealed beneficial effects of ozone, including reduced immobil ity, fewer errors in the radial arm maze, and increased open-arm exploration. Although seizure severity, latency, and duration were not significantly altered, seizure frequency showed a decreasing trend (p=0.067). Immunofluorescence for 8-OHdG revealed increased hippocampal oxidative DNA damage in the PTE group, which was attenuated following ozone treatment. Analysis of miRNA expression revealed downregulation in the PTE group, whereas ozone treatment resulted in overall upregulation. There was no statistically significant difference between miRNA expression results and the PTE+Ozone group (p=0.056–0.076). Ozone therapy mitigated oxidative stress and inflammation, improved redox homeostasis, enhanced cognitive and locomotor performance, and reduced hippocampal DNA damage in the PTE model. Furthermore, the observed upregulation of specific miRNAs following ozone treatment highlights a potential molecular mechanism contributing to its neuroprotective effects.
Clinical and molecular features of ovarian stimulation in peripubertal girls with mosaic turner’s syndrome
(Oxford University Press, 2026) Öktem, Özgür; Kalajahi, Hesam Ghafouri; Esmaeilian, Yashar; Benlioğlu, Can; Hela, Francesko; Yusufoğlu, Sevgi; Kalkan, Üzeyir; Turan, Volkan; Ata, Barış
STUDY QUESTION: Do peripubertal girls with mosaic Turner’s syndrome (TS) respond to ovarian stimulation (OS) for oocyte freezing as adult women with normal ovarian reserve? SUMMARY ANSWER: Clinical and molecular reproductive/endocrine features of OS in these patients are similar to those of adult females. WHAT IS KNOWN ALREADY: OS for oocyte freezing is quite a new concept in peripubertal and young adolescent girls with TS be cause ovarian tissue cryopreservation (OTC) does not have proven efficacy, likely due to already diminished ovarian reserve and ac celerated follicle atresia. No data are available in the literature regarding the molecular IVF characteristics of these cycles in this group of patients. We aimed to address this issue in the current study by analyzing gonadotropin receptor expression, response to gonadotropins, and steroidogenic function at the molecular level in four peripubertal patients aged 9, 12, 13, and 15 in comparison to control adult females with normal ovarian reserve undergoing OS for male factor infertility. STUDY DESIGN, SIZE, DURATION: This is a clinical and research study that simultaneously analyzes the clinical and molecular characteristics of OS in peripubertal young girls with TS between 2021 and 2023 at a university hospital and translational re search center. PARTICIPANTS/MATERIALS, SETTING, METHODS: All participants underwent OS using a progestin-primed protocol with recombi nant forms of FSH and LH, and final maturation was induced with recombinant hCG. Control patients who had normal ovarian re serve and underwent OS for male factor infertility were randomly recruited during the study period to simultaneously compare and analyze the clinical and molecular OS characteristics of the peripubertal TS cases. Luteinized mural granulosa cells obtained during oocyte retrieval procedures were used for the experiments. Cell culture, quantitative real-time PCR, immunoblotting, confocal time lapse live-cell imaging, and hormone assays were used. MAIN RESULTS AND THE ROLE OF CHANCE: All TS cases responded to gonadotropin stimulation. Nine mature oocytes were re trieved and vitrified in the 9-year-old prepubertal mosaic TS case after four cycles of OS with r-FSH (300 IU) and r-LH (150 IU)/day after a mean stimulation period of 9.72 ± 2.1 days. Eight mature oocytes were retrieved in the case aged 13 after three rounds of OS. The other cases, aged 12 and 15, underwent only one cycle of OS, and two mature oocytes from each were retrieved. The expression of FSH/LH receptors and steroidogenic enzymes, basal and gonadotropin-induced up-regulation in the expression of the steroidogenic enzymes, and estradiol and progesterone productions of the GCs of the TS patients were similar to those of adult control patients. Confocal immunofluorescence microscopy and live imaging revealed no differences in cholesterol uptake/trafficking or in staining patterns of the steroidogenic enzymes and their co-localization with mitochondria and cholesterol-laden lipid droplets. LIMITATIONS, REASONS FOR CAUTION: Findings were obtained from a limited number of mosaic TS patients. It is unclear if these findings are reproducible in non-mosaic peripubertal cases. Furthermore, no data are available yet regarding the post-thaw survival, fertilization, embryo development competency, euploidy status, and obstetrical outcomes of the vitrified oocytes of these patients. WIDER IMPLICATIONS OF THE FINDINGS: This study provides reassuring clinical and molecular evidence that OS for oocyte freez ing can be an option in young girls with mosaic TS who are not ideal candidates for OTC due to diminished ovarian reserve. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the School of Medicine, the Graduate School of Health Sciences, and the Research Center for Translational Medicine (KUTTAM) at Koc¸ University. The authors declare no competing interests. TRIAL REGISTRATION NUMBER: Not applicable.
