Browsing by Author "Keskintepe, Levent"

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Biotechnology and its application in the IVF treatment
(Current Biology, 2011-09) Yakut, Tahsin; Keskintepe, Levent; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.
Comparison of aneuploidy frequencies between in vitro matured and unstimulated cycles oocytes by metaphase comparative genomic hybridization (mCGH)
(Springer, 2012-05) Sher, Geoffrey; Keskintepe, Levent; Yakut, Tahsin; Karkucak, Mutlu; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; 0000-0002-8661-6126; 0000-0002-3434-2362; GIS-1493-2022; FDJ-7858-2022; 6602802424; 35388323500
A common observation after in vitro matured oocyte is that they yield poorer embryo quality compared to their in vivo counterparts. This study was designed to assess chromosomal status with metaphase comparative genomic hybridization after in vitro maturation (IVM) in unstimulated cycles and compare the results with those obtained after in vivo maturation. Patients without any obstetrical or gynecological pathology were admitted into the study. IVM oocytes were collected 36 h post hCG and matured in vitro at 37A degrees C in 5% O-2, 6% CO2, and 89% air for 36 h. All matured (metaphase II) oocytes were subject to polar body 1 (PB-1) biopsy and vitrified individually. PB-1 samples were transferred into 0.25 cc PCR tubes containing 2.5 mu l of PBS. PB-1 samples from 12 IVM patients were studied. Twenty-six out of 63 PB-1 samples (41%) were determined as euploid and 37 samples (59%) were aneuploid, whereas these values were 42% euploid and 58% aneuploid in the control group (in vivo matured oocytes). No statistical differences were found between the IVM and the control groups for euploid-aneuploid samples (P = 0.900). More aneuploidy was observed on chromosomes 11, 13, 15, 21, and 22 after IVM. Results show a non-significant rate of abnormal PB-1 formation after IVM compared to in vivo maturation. More aneuploidy was observed in chromosomes 11, 13, 15, 21, and 22 in the IVM group.
Effect of CZB medium on the two cell block of preimplantation mouse emryos
(TÜBİTAK, 2001) Bağış, H.; Keskintepe, Levent; Odaman, Hande; Sağırkaya, Hakan; Uludağ Üniversitesi/Veteriner Fakültesi/Döllerme ve Suni Tohumlama Anabilim Dalı.; AAH-8821-2021; 6602400461
This experiment was designed to determine the effects of CZB medium on in vitro culture of murine embryos obtained from FVB/N, CD-1, and CB6F1 strains. Pronuclear stage embryos were recovered from superovulated and mated females 17 h post-hCG. Two-cell stage block, morula and blastocyst stages were used as the end point of the experiments. There is no statistical difference among strains and media for the development to the two-cell stage. However, more FVB/N embryos (88.3 and 82.4%) than CD-1 (57.4 and 57.1%) and CB6F1 (69.8 and 28.9%) reached the 3-8 cell stage in CZB and M16 media, respectively. CB6F1 embryos developed better (69.8%) in CZB than in M16 (28.9%). Morula development for FVB/N embryos was superior (75.0%) in CZB when compared to M16. Collectively, these data suggest that there are strain differences for in vitro embryo development and the in vitro culture medium has a profound effect on in vitro development.
Influences of cumulus cells during in vitro fertilization of mouse oocytes in different mouse strains
(TÜBİTAK, 2001) Bağış, H.; Keskintepe, Levent; Odaman, Hande; Çetin, Seyfettin; Sağırkaya, Hakan; Uludağ Üniversitesi/Veteriner Fakültesi.; 6602400461
In this study, the influences of cumulus cells during in vitro fertilization (IVF) and their subsequent effects on mouse embryo development in vitro were studied in inbred and hybrid strain mice. Embryos at the 2-cell stage obtained after in vitro fertilization were transferred to the oviduct of foster mothers to assess their implantation rate. Mouse oocytes, which were intact at the time of in vitro fertilization, demonstrated less polyspermic fertilization and more blastocyst development than those inseminated without any cumulus cells. The data demonstrate that more oocytes were arrested at the 2-cell stage in groups that contained no cumulus cells. There was no statistical difference between cumulus-enclosed and cumulus-free groups for embryo implantation. Data suggest that although there was no difference in terms of implantation rate, more blastocyst stage embryos were obtained from cumulus cell enclosed oocytes. Therefore, we suggest that cumulus cells play many roles during in vitro fertilization, and they should be intact during in vitro fertilization.
Oocyte karyotyping by comparative genomic hybrydization provides a highly reliable method for selecting "competent" embryos, markedly improving in vitro fertilization outcome: A multiphase study
(Elsevier, 2007-05) Aher, Geoffrey; Ginsburg, Mike; Maassarani, Ghanima; Kotze, Dirk; Keskintepe, Levent; Keskintepe, Meral; Baltacı, Volkan; Ünsal, Evrim; Yakut, Tahsin; Uludağ Üniversitesi/Tıp Fakültesi.
Objective: To assess the karyotypic relationship between prefertilized/postfertilized oocytes and embryos using comparative genomic hybridization (CGH) on polar body-1 (PB-1), PB2, and blastomere biopsies and to evaluate IVF outcomes after transfer of blastocysts derived from euploid oocytes. Design: Prospective cohort. Setting: Medical center. Patient(s): Phase1: Fourteen oocyte donors (23-29 years). Phase 2: Forty-one healthy embryo recipients aged 29-43 years free of endometrial implantation dysfunction. In 30 cases own eggs were used. Eleven women used donated oocytes. Intervention(s): Phase 1: PB-1 biopsies followed intracytoplasmic sperm injection (ICSI), PB-2, and day 3 blastomere biopsies. Phase 2: PB-1 biopsy followed by ICSI using normal sperm and the subsequent embryo transfer of ≤2 blastocysts derived from euploid oocytes. Comparative genomic hybridization on all DNA derived from phase 1 and 2 biopsies. Main Outcome Measure(s): Pregnancy and implantation rate. Result(s): Phase 1: 39% of oocytes and 88% of zygotes were euploid; >95% progressed to blastocysts. Mosaicism as evidenced by euploid oocytes developing into aneuploid zygotes or embryos occurred in 13% of concepti. Phase 2: Six of 30 women using own eggs, who failed to produce euploid oocytes, were cancelled. Thirty-five women underwent embryo transfers with ≤2 (mean, 1.3 ± 0.7) blastocysts derived from euploid oocytes. The ongoing pregnancy/implantation rates per embryo transfer were 74% and 82%, respectively. Conclusion(s): Transferring euploid embryos markedly improved IVF outcome. These findings, if corroborated, could initiate a paradigm shift in assisted reproductive technology (ART).
Reanalysis of human blastocysts with different molecular genetic screening platforms reveals significant discordance in ploidy status
(Springer/Plenum Publishers, 2016-06-30) Tortoriello, Drew V.; Dayal, Molina; Beyhan, Zeki; Yakut, Tahsin; Keskintepe, Levent; Uludağ Üniversitesi/Tıp Fakültesi//Tıbbi Genetik Anabilim Dalı.; 0000-0002-0829-0992; 6602802424; 6602492477
The objective of this study is to determine mosaicism and its effect on blastocysts; abnormal blastocysts determined by molecular testing were sequentially biopsied and retested. We re-biopsied 37 blastocyst-stage abnormal embryos from eight patients, which were reanalyzed to determine the level of concordance between biopsies and inter-laboratory congruence between reputable commercial PGS laboratories. The main outcome measures were intra-embryo variation between sequential embryo biopsies and inter-laboratory variation between two PGS laboratories. The compatibility between both aCGH and NGS was found to be 11 % (3/27). Importantly, 9/27 (33 %) of embryos originally reported to be aneuploid, upon repeat assessment, were found to be euploid. The concurrence for SNP array and NGS was 50 % (3/6), and 17 % (1/6) of these abnormal embryos tested normal upon re-evaluation with NGS. NGS resulted 41 % (11/27) normal results when 27 of CGH abnormal embryos were retested. Concordance between aCGH and NGS was 4 % (1/27) whereas in three instances, gender discrepancy was observed with NGS when aCGH abnormal embryos were reanalyzed. The results of these studies reinforce the prevalence of inconsistencies during PGS evaluation of trophectoderm biopsies possibly due to variations in platform sensitivity and heightening concerns over the clinical tractability of such technology in human ARTs..
Reanalysis of human blastocysts with different molecular genetic screening platforms reveals significant discordance in ploidy status-editorial comment
(Lippincott Williams & Wilkins, 2016-11) Tortoriello, Drew V.; Dayal, Molina; Beyhan, Zeki; Yakut, Tahsin; Keskintepe, Levent; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; 6602802424; 6602492477