Researcher: Öktem, Özgür
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Öktem, Özgür
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Publication Metadata only The clinical utility of a pulsed bipolar system and its electrosurgical device during total laparoscopic hysterectomy(Mary Ann Liebert, Inc., 2017) N/A; N/A; Mısırlıoğlu, Selim; Türkgeldi, Engin; Boza, Ayşen; Öktem, Özgür; Ata, Mustafa Barış; Urman, Cumhur Bülent; Taşkıran, Çağatay; Doctor; Faculty Member; Doctor; Faculty Member; Faculty Member; Faculty Member; Faculty Member; N/A; School of Medicine; N/A; School of Medicine; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; N/A; Koç University Hospital; N/A; N/A; N/A; N/A; N/A; 329649; N/A; 102627; 232576; 12147; 134190Objective: The aim of this research was to evaluate the efficacy and safety of the PlasmaKinetic (PK) PKS OMNI (R) (Gyrus ACMI, Maple Grove, MN) sealing device in laparoscopic hysterectomy. Materials and Methods: For this retrospective observational study, 60 patients who underwent multiport total laparoscopic hysterectomy between January 2014 and January 2015 in a tertiary-care university-based teaching hospital and an academically affiliated hospital were included in this study. The PKS OMNI is a bipolar electrosurgical device that takes energy from a PK generator workstation G400. This pulsed wave system has two different modes; cutting (High Cut 1,2,3) and coagulation (Vaporization 1,2,3). Results: Records of 60 patients were analyzed. The median age was 50 (range: ages 40-84), median body mass index was 26kg/m(2) (range: 22-32kg/m(2)), and median parity was 2 (range: 1-8). The median total operation time was 100 minutes (range: 70-240 minutes), estimated blood loss was 80mL (range: 30-250mL), and uterine weight was 207g (range: 50-900g). Degree of Surgical Difficulty and postoperative pain scores at rest were evaluated with a visual analogue scale system, from 0 to 10, and the medians of these scores were 5 (range: 3-7) and 4 (range: 2-6), respectively. The median recovery time of bowel movement was 16 hours (range: 8-26 hours), median spontaneous urination time was 7 hours (range: 4-29 hours), and median postoperative mobilization time was 8 hours (range: 6-10 hours). Conversion to laparotomy was needed in 1 patient due to severe pelvic adhesions. The median duration of hospital stay was 2 days (range: 2-4 days). Vaginal cuff dehiscence was detected in 1 (1.7%) patient who engaged in sexual intercourse on the 122nd day after surgery. Cuff cellulitis in 1 (1.7%) patient and unexplained fever in 1 (1.7%) patient were the other recorded complications. The median follow-up time was 12 months (range: 6-17 months). Conclusions: The PKS OMNI is a novel, underused energy modality that promotes quick recovery and acceptable operation time with minimal blood loss.Publication Metadata only Understanding follicle growth in vitro: are we getting closer to obtaining mature oocytes from in vitro-grown follicles in human?(Wiley, 2017) Güzel, Yılmaz; N/A; Öktem, Özgür; Faculty Member; School of Medicine; 102627Obtaining and fertilizing mature oocytes from immature follicles that were grown outside the body has conceptually attracted scientists for centuries, with initial attempts first documented in the 19th century. Significant progress has been made since then, due in part to a better understanding of folliculogenesis and improved techniques of in vitro follicle growth. Indeed, in vitro growth is now considered a reasonable approach to preserve or restore fertility when immature follicles and their oocytes need to be grown and matured outside the body. Certain patients would benefit from in vitro follicle growth, particularly those who carry a risk of cancer re-seeding after grafting of frozen-thawed ovarian tissue or who are at the risk of premature ovarian failure due to several intrinsic ovarian defects and genetic mutations that lead to accelerated follicle atresia and early exhaustion of the ovarian reserve. This review provides an update on the current status of in vitro growth of preantral human follicles, from initial efforts to the most recent achievements.Publication Metadata only A comprehensive comparative transcriptional and translational analyses of the impact of ovarian response type, stimulation protocol and mode of trigger on the luteal function(Elsevier Science Inc, 2018) Seyhan, A; Yakın, Kayhan; Ata, Mustafa Barış; Öktem, Özgür; Bildik, Gamze; Urman, Cumhur Bülent; Faculty Member; Faculty Member; Faculty Member; Teaching Faculty; Faculty Member; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; 106822; 182910; 102627; N/A; 12147Objective: We aimed to compare molecular characteristics of the luteal granulosa cells between natural vs. stimulated IVF cycles in good and poor-responders. Design: Translational research study. Materials and Methods: Luteinized granulosa cells were obtained from good (n=154) and poor responder (n=64) IVF patients comparable for age, type and dose of gonadotropin and IVF etiology. Good-responders (4-15 oocytes) underwent natural (n=22), GnRH agonist (long protocol n=44) and antagonist IVF cycles triggered with rec-hCG (n=46) or GnRH agonist leuprolide acetate (n=42). Poor-responders fulfilling the Bologna criteria consisted of 64 patients undergoing GnRH antagonist protocol triggered with hCG (n=36) or hCG+GnRH agonist (n=28). Results: In the good-responders, natural cycle (NC) granulosa cells were significantly more viable (88%) compared to the stimulated IVF cycles (66%, 64% and 37% for agonist and antagonist cycles triggered with hCG and agonist respectively, p<0.05). The mRNA expression of steroidogenic enzymes (SCC, stAR, 3B-HSD, 17B-HSD and aromatase), LH receptor and VEGF and in vitro E2 and P productions were comparable between hCG-triggered agonist and antagonist cycles, but significantly higher than NC in the first days of culture. However, on the following days their hormone productions and viability began to decline very rapidly with the most drastic decrease being observed in the agonist triggered cycles. By contrast, NC granulosa cells maintained their viability and produced E 2 and P in increasing amounts in culture up to six days. The expression of anti-apoptotic genes (AKT-1, BCL2-L2) were significantly lower, and pro-apoptotic genes (BAD, BID, BAX, Cas3) were significantly higher in the stimulated cycles particularly in the agonist triggered ones compared to NC granulosa cells. Pulse exposure to cisplatin induced apoptosis only in a small fraction of the cells from the NCs whereas the same exposure caused massive apoptosis in the cells of the stimulated cycles (27% vs. 78% respectively, p<0.01). In the poor-responders both viability and steroidogenic activity of the cells were more severely reduced compared to the antagonist cycles of the good-responders. There were no significant differences between hCG and hCG+agonist triggered cycles in terms of viability, hormone production, VEGF and LH receptor expressions in the luteal granulosa cells. Conclusions Reduced survival and increased apoptosis of luteal granulosa cells leading to defective steroid production in stimulated cycles in comparison to natural ones may at least in part explain why luteal phase is defective and requires exogenous P supplementation for support in these cycles. Also dual trigger does not appear to improve luteal function in the poor-responders.Publication Metadata only The expressions of ovarian steroidogenic enzymes do not increase proportionally after FSH, creating a shunting that promotes progesterone output in the granulosa cells without luteinization(Oxford University Press (OUP), 2016) Seyhan, A.; Keles, I.; Balaban, B.; N/A; N/A; N/A; N/A; Akın, Nazlı; Bildik, Gamze; Urman, Defne; Urman, Cumhur Bülent; Öktem, Özgür; Master Student; Teaching Faculty; Master Student; N/A; Faculty Member; Faculty Member; Graduate School of Health Sciences; School of Medicine; Graduate School of Health Sciences; N/A; School of Medicine; School of Medicine; N/A; N/A; N/A; N/A; 12147; 102627N/APublication Metadata only Molecular evidence against the preventive actions of GnRH agonists in chemotherapy induced damage in human ovary and granulosa cells(2015) Güzel, Y.; Urman, B; N/A; Bildik, Gamze; Akın, Nazlı; Taşkıran, Çağatay; Selek, Uğur; Öktem, Özgür; Teaching Faculty; Master Student; Faculty Member; Faculty Member; Faculty Member; School of Medicine; Graduate School of Health Sciences; School of Medicine; School of Medicine; School of Medicine; Koç University Hospital; N/A; N/A; 134190; 27211; 102627N/APublication Metadata only Sphingosine-1-phosphate protects human ovarian follicles from apoptosis in vitro(Elsevier, 2018) Güzel, Yılmaz; Bildik, Gamze; Öktem, Özgür; Teaching Faculty; Faculty Member; School of Medicine; School of Medicine; N/A; 102627Objective(s): We aimed to analyze if anti-apoptotic agent sphingosine-1-phosphate offers protection against in vitro follicle atresia during culture of human ovarian cortical samples. Study design: A translational research study of ex-vivo and in-vitro models of human ovarian tissue. Material and methods: Ovarian cortical tissue fragments (1 x 0.5 cm) were obtained from young patients (n = 15 mean age +/- SD: 29.4 +/- 2.5) undergoing laparoscopic excision of benign ovarian cysts. The samples were cultured for 4 days in 24-well format culture plate using conventional culture techniques. S1P was added to culture media at 200 and 400 mu M concentrations. At the end of culture period the samples were processed for both histomorphological assessment and detection of apoptosis with immunohistochemistry and western blot methods using apoptosis marker cleaved caspase-3. In vitro estradiol (E-2) and AMH productions of the samples were measured with ELISA. Follicle counts were expressed as the mean number of follicles per mm(2). Results: The mean numbers of primordial and secondary follicles were 3.2 +/- 0.4 and 0.7 +/- 0.2 respectively, in the fresh fixed uncultured samples. After four days of culture their numbers were significantly decreased to 0.8 +/- 0.2 (p < 0.01) and 0.1 +/- 0.05 (p < 0.05) respectively, in the control samples cultured without S1P compared to fresh fixed samples. SIP treatment decreased follicle atresia and significantly higher number of primordials (2.3 +/- 0.3, p < 0.01) and secondary follicles (0.5 +/- 0.1, p < 0.05) survived in the samples after 4 day culture period compared to those cultured without SIR In line with this there was dose-dependent decrease in the protein expression of cleaved caspase-3 on western blot and in the number of apoptotic follicles stained positive for cleaved caspase-3 on immunohistochemistry in the samples incubated with S113 at 200 and 400 mu M concentrations. Furthermore, those samples incubated with SlP produced significantly higher amounts of E2 (2339 +/- 321 vs. 1156 +/- 125 pg/mL respectively, p < 0.01) compared to control samples. Conclusions: These results suggest that S1P promotes follicle survival in human ovarian cortical samples in vitro. (C) 2018 Elsevier B.V. All rights reserved.Publication Metadata only Ovarian endometriomas are heterogenous for the steroidogenic function and the expression of estrogen and progesterone receptors(Oxford Univ Press, 2021) N/A; N/A; N/A; N/A; Esmaeilian, Yashar; Yıldız, Şule; Yakın, Kayhan; Öktem, Özgür; Researcher; Faculty Member; Faculty Member; Faculty Member; N/A; School of Medicine; School of Medicine; School of Medicine; N/A; 134205; 106822; 102627N/APublication Metadata only In-vitro AMH production of ovarian tissue samples in culture correlates with their primordial follicle pool(Elsevier, 2020) N/A; N/A; N/A; N/A; N/A; N/A; Vatansever, Doğan; İncir, Said; Bildik, Gamze; Taşkıran, Çağatay; Öktem, Özgür; Faculty Member; Faculty Member; PHD Student; Faculty Member; Faculty Member; School of Medicine; School of Medicine; Graduate School of Health Sciences; School of Medicine; School of Medicine; N/A; 193687; 175430; N/A; 134190; 102627Objective: We aimed to investigate if there is a correlation between in-vitro AMH production and primordial follicle reserve of the ovarian cortical samples in culture. Methods: Seven patients undergoing laparoscopic excision of ovarian dermoid cysts were included in the study. 0.5 x 0.5 cm of ovarian cortical samples embedded within the cyst wall were removed and cultured for one day. Then, the cultured cortical pieces were fixed, paraffin-embedded and serially sectioned for histormorphometric analysis. AMH and estradiol (E-2) production of the samples after one-day culture period were measured in the spent culture media. Primordial follicle density was expressed as the number of primordial follicles per mm(2). Pearson correlation and linear regression analyses were applied. Results: The mean age of the patients was 29.2 +/- 6.8 (ranging from 18 to 36). There was a negative correlation between age and PF density (r=-0.92, %95CI: -0.99 to -0.76, p <0.001). In-vitro AMH level of the cortical samples was significantly associated with age (R-2 = 0.67, p = 0.023), primordial follicle density (R-2 = 0.71, p = 0.015). There was a borderline significance between in-vitro levels of AMH and E-2 level (R-2 = 0.55, p = 0.058). A similar comparison could not be made for secondary follicles (preantral and small antral follicles) because of their rarity in the histological sections analyzed. Conclusions: This histomorphometric study provides evidence that in-vitro AMH production of the ovarian cortical samples reflects primordial follicle pool of the samples. (C) 2020 Elsevier B.V. All rights reserved.Publication Metadata only FSH stimulation promotes progesterone synthesis and output from human granulosa cells without luteinization(Oxford Univ Press, 2017) Alper, Ebru; Balaban, Basak; N/A; Öktem, Özgür; Akın, Nazlı; Bildik, Gamze; Yakın, Kayhan; Urman, Cumhur Bülent; Faculty Member; Master Student; Teaching Faculty; Faculty Member; Faculty Member; School of Medicine; Graduate School of Health Sciences; Graduate School of Health Sciences; School of Medicine; School of Medicine; 102627; N/A; N/A; 106822; 12147STUDY QUESTION: Can granulosa cells produce progesterone (P) in response to FSH stimulation? SUMMARY ANSWER: FSH actively promotes P synthesis and output from granulosa cells without luteinization by up-regulating the expression and increasing enzymatic activity of 3 beta-hydroxysteriod dehydrogenoase (3 beta-HSD), which converts pregnenolone to P. WHAT IS KNOWN ALREADY: Serum P level may rise prematurely prior to ovulation trigger in stimulated IVF cycles and adversely affect implantation and clinical pregnancy rates by impairing endometrial receptivity. STUDY DESIGN, SIZE, DURATION: A translational research study. PARTICIPANTS/MATERIALS, SETTING, METHODS: Human ovarian cortical samples (n = 15) and non-luteinizing FSH-responsive human mitotic granulosa cell line (HGrC1) were stimulated with rec-FSH at 12.5, 25 and 50 mIU/ml concentrations for 24 and 48 h. FSH receptor expression was knocked-down and up-regulated in the granulosa cells using short hairpin RNA (shRNA) technology and activin-A administration, respectively. The expressions of the steroidogenic enzymes were analyzed at mRNA level by real-time quantitative RT-PCR, and protein level by western blot and immunoprecipitation assay. The enzymatic activity of 3 beta-HSD was measured using a spectrophotometric method. In vitro estradiol (E2) and P productions of the cells before and after FSH stimulation were measured by electrochemiluminescence immunoassay method. MAIN RESULTS and THE ROLE of CHANCE: Stimulation of the HGrC1 cells with FSH resulted in a dose-dependent increase in the mRNA and protein level of 3 beta-HSD. Overall, when all time points and FSH doses were analyzed collectively, FSH significantly up-regulated the mRNA expression of its own receptor (3.73 +/- 0.06-fold, P < 0.001), steroidogenic acute regulatory protein (stAR, 1.7 +/- 0.03-fold, P < 0.01), side-chain cleavage enzyme (SCC, 1.75 +/- 0.03-fold, P < 0.01), aromatase (4.49 +/- 0.08-fold, P < 0.001), 3 beta-HSD (1.68 +/- 0.02-fold, P < 0.01) and 17 beta-hydroxy steroid dehydrogenase (17 beta-HSD, 2.16 +/- 0.02-fold, P < 0.01) in the granulosa cells. Expression of 17 alpha-hydroxylase (17 alpha-OH, 1.03 +/- 0.01-fold P > 0.05) did not significantly change. Similar changes were observed in the protein expression analysis of these enzymes on western blotting after FSH stimulation. FSH significantly increased 3a-HSD, 17 beta-HSD and aromatase in a dose-dependent manner but did not affect 17 alpha-OH. Protein expression of P was increased along with 3a-HSD after FSH stimulation, which was further evidenced by immunoprecipitation assay. Enzymatic activity of 3 beta-HSD was significantly enhanced by FSH administration in the HGrC1 cells in a dose-dependent manner. In line with these findings P output (1.05 +/- 0.3 vs. 0.2 +/- 0.1 ng/ml, respectively, P < 0.001) from the samples stimulated with FSH were significantly increased along with E2 (1918 +/- 203 vs. 932 +/- 102 pg/ml, respectively, P < 0.001) compared to unstimulated controls. FSH-induced increase in 3 beta-HSD expression was amplified and reversed in the HGrC1 cells when FSH receptor expression was up-regulated by activin-A and down-regulated with shRNA, respectively. LIMITATIONS and REASONS FOR CAUTION: As only the effect of FSH was studied we cannot extrapolate our findings to the potential effects of HMG and recombinant LH. WIDER IMPLICATIONS of THE FINDINGS: This data provides a molecular explanation for the largely unexplained phenomenon of P rise during the follicular phase of gonadotropin stimulated IVF cycles. Our findings may progress the research to uncover potential mechanisms for preventing premature P rise that appears to be associated with inferior outcomes in women undergoing IVF.Publication Metadata only Utility of pks omni(®) electrosurgical device in laparoscopic hysterectomy(Elsevier, 2015) N/A; Urman, Cumhur Bülent; Mısırlıoğlu, Selim; Bengisu, Hale; Türkgeldi, Engin; Ata, Mustafa Barış; Öktem, Özgür; Taşkıran, Çağatay; Faculty Member; Doctor; Doctor; Faculty Member; Faculty Member; Faculty Member; Faculty Member; Doctor; School of Medicine; N/A; N/A; School of Medicine; School of Medicine; School of Medicine; School of Medicine; N/A; Koç University Hospital; 12147; N/A; N/A; 329649; 182910; 102627; 134190; N/AStudy Objective: The aim of this study is to evaluate the efficacy and safety of PKS Omni ® sealing device in laparoscopic hysterectomy. Design: Retrospective, non-randomized observational cohort. Setting: University hospital and academic affiliated private hospital. Patients: Patients with benign diseases undergoing multi-port laparoscopic hysterectomy between 2014 and 2015. Intervention: PKS Omni ® (Gyrus ACMI Inc..,USA) is bipolar electrosurgical device takes the energy from Plasmakinetic generator workstation G400, and this pulsed wave system involves two different modes; cutting (HC 1,2,3) and coagulation (VP1,2,3). We choosed VP3-power level 110 for coagulation and for cutting HC2-power level 50 according to tissue empedance. All the cases in this study were performed with a plasma kinetic energy system, and its electosurgical device PKS Omni ® The surgical operations were carried out by two surgeons who are experienced in gynecologic oncology and advance endoscopic surgery. Measurements and Main Results: Fifty-nine patients were evaluated, and all of the operations were completed by laparoscopy, but one is needed conversion to laparotomy because of severe adhesions between bowel and pelvic viscera. The median operating time was 100 minutes (60-185 min), and estimated blood loss was 20 ml (10-50 ml). Transfusion was not required. Recovery of gastrointestinal activity is occurred at post-operative 16 hour (12-24 houtr). Urinary catheter was not placed pre-or post operative, and spontaneous urinary activity started at 6 hour after operation (4-8 hour). Post-operative abdominal pain at rest was noted due to VAS (visual analog scale) score 0 to 10; 0 referring to no pain and 10 to unbearable pain. VAS score was 2 (0-6), and signified mild pain. Conclusion PKS Omni is a novel, underused energy modality that promotes quick recovery and acceptable operation time with minimal blood loss and excellent post-operative pain scores.