Yazar "Demir K." seçeneğine göre listele

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    Comparison of two different media for in vitro production of dog embryos
    (Veteriner Fakultesi Dergisi, 2010) Evecen M.; Cirit U.; Demir K.; Karaman E.; Bakirer G.; Hamzao?lu A.I.; Birler S.
    Embryo production via in vitro fertilization and nuclear transfer has been accomplished in the dog, and the transfer of the cloned embryos has recently resulted in the birth of puppies. However, the efficiency of these technologies is still very limited. Until now, only two morulas and single blactocyst have been achieved in vitro. Therefore, the aim of the present study was to examine the effects of two different media (mSOF and TCM 199) on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) of immature dog oocytes. The study was performed in two steps. At the first step, the effects of two different media, on IVM of dog oocytes were investigated. At the end of the IVM period, the nuclear maturation rates were evaluated by aceto-orcein staining method. At the second step, after the IVM period the oocytes inseminated with fresh spermatozoa for 24 h and left for IVC for 7 d. At the end of the IVC period, embryonic development was assessed by microscopic observation at 24 h intervals and then fixed and stained by the same method. Consequently, maturation rates of oocytes in mSOF medium were significantly higher than those of the TCM 199 (P<0.001). After 7 d of the IVC period, only one oocyte was cleaved in the TCM 199, while eight oocytes cleaved and one of them developed to morula stage in mSOF medium group (P=0.037).
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    Öğe
    Effect of exposure duration to the vitrification medium on the post thaw development of in vitro derived bovine embryos
    (2012) Özdaş O.B.; Cirit U.; Demir K.; Bacinoğlu S.; Baran A.; Pabuccuoğlu S.; Irez T.
    Transfer of frozen embryos enables the establishment of elite herds, control of diseases and storage of genetic materials for longer periods. However, although intercontinental transfer of frozen embryos is possible, post-thaw degenerations are encountered and pregnancy rates are not at the expected level. Embryos especially degenerate during freezing and thawing procedures. These degenerations are thought to be due to the exposure time and toxic effects of used cryoprotectants. In this study slaughtered cattle ovaries were used. Oocytes were collected from ovaries using the aspiration method and matured in their own group in 700 microliter TCM-199 for 22-24 h at a gas atmosphere of 5% CO 2, 5% O2, and 90% N2 at 38.8 °C. Matured oocytes were fertilized for 18-24 h in IVF-TALP medium. After fertilization cleavage was 67.05% (865/1290) at 48th h. Embryos were cultured up to early blastocyst-blastocyst stage (34.91%; 302/865) in SOF medium supplemented with 10 % FCS for 7 days at a gas atmosphere of 5% CO 2, 5% O 2, and 90% N 2 at 38.8 °C. 302 embryos at the early blastocyst stage were frozen after an exposure to vitrification solution for various time periods (15, 30, 60, and 90 sec). Four groups have been established for this purpose (Groups 1, 2, 3, 4). Each group has included 67, 64, 63 and 60 embryos, respectively. All embryos were first kept in PBS solution containing 10% Glycerol + 10% FCS (Vs1) for 5 minutes and then in PBS containing 10% Glycerol+10% FCS+20% Ethylene Glycol (Vs2) solution for 5 minutes. Later, embryos were taken to straw containing vitrification solution (Vs3), 25% Glycerol + 10% FCS + 25% Ethylene Glycol + 0.1 M sucrose, and exposed for various time periods (15, 30, 60 and 90 sec), then frozen by dipping into liquid nitrogen. After thawing (37 °C) embryos were washed several times in washing medium supplemented with 0.5 M sucrose and SOF medium, then embryos of each group were incubated again for another 48 hours. Chi-square test was used in this study. Post thaw development to expanded blastocyst stage was highest in Group 1 with 52.2% (35/67) followed by Group 2 with 45.3% (29/64), Group 3 with 22.2% (14/63) and Group 4 with 5% (3/60). No statistical significance was observed between Groups 1 and 2. The statistical difference between Group 1 and 3 and between Group 1 and 4 were at P<0.01 and P<0.001 levels, respectively.
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    Öğe
    Isolated mitral valve prolapsus does not affect left ventricular function
    (2011) Demir K.; Koc F.; Can I.; Vatankulu M.A.; Yazici M.; Ülgen M.S.
    Aim: Idiopathic mitral valve prolapsus (MVP) is characterized by myxomatous degeneration of mitral valve. The most common determinant of cardiovascular mortality in patients with MVP is left ventricular (LV) dysfunction. Therefore we aimed to evaluate LV functions of cases with isolated MVP by tissue Doppler echocardiography (TDE). Method: Twenty five patients with MVP (mean age, 31±12 years) were enrolled the study as MVP group. Control group was consisted 20 age and sex matched patients (mean age, 34±9 years) were enrolled to this study. LV functions were detected by using conventional echocardiography and TDE. Myocardial peak systolic (Sm), early (Em) and late (Am) diastolic filling velocities, Em/Am, isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT) and ejection time (ET) were obtained in the basal segments of the inferior-septal and lateral wall. Myocardial performance index (MPI) was calculated. Result: Mild degree mitral regurgitation was present in 10 (40%) of patients with MVP, and moderate degree mitral regurgitation was present in 2 (8%) of patients. No difference was found between the two groups with regard to diastolic parameters. TDE-derivated MPI values were similar in all segments in two groups. There was significant difference between the two groups with regard to LV mean Sm and lateral wall Sm (11.6±2.8 vs. 9.4±1.0, p=0.001; 13.0±3.9 vs. 9.2±2.3, p=0.001 respectively). Conclusion: Isolated MVP without significant mitral regurgitation does not affect LV diastolic functions and MPI. However, Sm of late ral wall and LV mean was higher in patients with MVP than patients without MVP.