Meltem Ozgüner

T.C. Süleyman Demirel Üniversitesi, Hamitabat, Isparta, Turkey

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Publications (5)8.16 Total impact

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    ABSTRACT: The accidental placement of a back-wall stitch is a mistake easily made by microsurgeons during an end-to-side (ETS) anastomosis, which is technically more difficult compared with an end-to-end (ETE) anastomosis. The thrombogenic effects of a back-wall stitch may aggravate the already existing turbulence and therefore thrombus-prone ETS anastomosis. We investigated this dangerous combination by applying a purposeful back-wall stitch model (PBWS) in an ETS microarterial anastomosis model in various configurations the rat carotid and femoral arteries. We performed femoral and carotid artery bypass grafts via two ETS anastomosis. Carotid (n=28) and femoral (n=28) artery groups were equally divided into four different subgroups according to PBWS placement: Control (no PBWS) and 30-degree, 60-degree, and 90-degree subgroups with PBWS located at 30, 60, and 90 degrees, respectively. We found that there were no significant patency differences with respect to vessel type, PBWS placement, or time of assessment. The results of our current study and previous studies demonstrate that a PBWS in the ETS anastomosis does not have a major effect on thrombus formation. We think that an inadvertent back-wall stitch in the ETS anastomosis may not be a significant cause of thrombosis alone but in combination with retained thrombogenic material into lumen can contribute to thrombus.
    No preview · Article · Aug 2008 · Journal of Reconstructive Microsurgery
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    ABSTRACT: We have investigated the effect of subchronic administration of methidathion (MD) on ovary evaluated ameliorating effects of vitamins E and C against MD toxicity. Experimental groups were as follows: control group; a group treated with 5 mg/kg body weight MD (MD group); and a group treated with 5 mg/kg body weight MD plus vitamin E and vitamin C (MD + Vit group). MD and MD + Vit groups were given MD by gavage five days a week for four weeks at a dose level of 5 mg/kg/day by using corn oil as the vehicle. Serum malondialdehyde (MDA: an indicator of lipid peroxidation) concentration, serum activity of cholinesterase (ChE), and ovary histopathology were studied. The level of MDA increased significantly in the MD group compared with the control (P < 0.005). Serum MDA decreased significantly in the MD + Vit group compared with the MD group (P < 0.05). The activities of ChE decreased significantly both in the MD and MD + Vit groups compared with the controls ( P < 0.05). However, the decrease in the MD + Vit groups was less than in the MD group; the ChE activity in the MD + Vit group was significantly higher compared with MD group (P < 0.05). Number of ovarian follicles were significantly lower in the MD group compared to the controls (P < 0.05). Number of atretic follicles were significantly higher in the MD group than in the controls (P < 0.05). Follicle counts in MD + Vit group showed that all types of ovarian follicles were significantly higher, and a significant decrease in the number of atretic follicles compared with the MD group (P < 0.05). In conclusion, subchronic MD administration caused an ovarian damage, in addition, LPO may be one of the molecular mechanisms involved in MD-induced toxicity. Treatment with vitamins E and C after the administration of MD reduced LPO and ovarian damage.
    Full-text · Article · Jun 2007 · Human & Experimental Toxicology
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    ABSTRACT: The role of reactive oxygen species (ROS) in various diseases of the female reproductive tract has been shown, and oxidative stress is an important component of the mechanism of toxicity of OPIs. Methyl parathion (MPT) is one of the most widely used organophosphate insecticides (OPIs) in agriculture. The aim of the study was to elucidate the effect of subchronic MPT exposure on lipid peroxidation and serum activities of cholinesterase (ChE), and the protective effects of combination of antioxidant Vitamins E and C in rats. Additionally, histopathological and immunohistochemical changes in endometrium were aimed to be examined. Three groups of rats were used in the experiment. The first group was treated with 5mg/kg MPT; the second group was treated with 5mg/kg body weight MPT plus Vitamin E and Vitamin C (MPT+Vit); and the third group was given only corn oil (control). MPT and MPT+Vit groups were given MPT by gavage 5 days a week for 4 weeks at a dose level of 4mg/(kgday) by using corn oil as the vechicle. Vitamins E and C were injected at doses of 50mg/kg i.m. and 20mg/kg body weight i.p. Histopathological and immunohistochemical examinations for caspase-3 and caspase-9 were accomplished in the endometrium. The level of malondialdehyde (MDA) increased significantly in the MPT group compared with the control group (p<0.05). MDA significantly decreased in the MPT+Vit group compared with the MPT group (p<0.05). Administration of Vitamins E and C along with MPT significantly reduced the histopathological changes and the extent of apoptosis. In conclusion, subchronic MPT administration caused endometrial damage and that treatment with a combination of Vitamins E and C reduced endometrial damage caused by MPT.
    Full-text · Article · Mar 2007 · Environmental Toxicology and Pharmacology
  • Serdar Nasir · Mustafa Asim Aydin · Meltem Ozgüner
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    ABSTRACT: Many microsurgeons experience inadvertent back-wall stitch as a cause of immediate anastomotic failure. To investigate this factor as a possible cause of delayed arterial anastomotic failure that does not appear in the operation room, a purposeful back-wall stitch (PBWS) model of microarterial anastomosis was applied in various configurations on femoral and carotid arteries of rats. Carotid (n = 28) and femoral (n = 28) artery groups were equally divided into 4 different subgroups according to the type of PBWS. Control subgroups had no PBWS. Thirty-degree, 60-degree, and 90-degree subgroups had PBWS located at 30, 60, and 90 degrees, respectively. Patencies were assessed at 60 minutes and 24 hours. Immediate milking test demonstrated normal anterograde refilling in all anastomoses. PBWS increased thrombosis in femoral arteries, while it did not increase it in the carotid at either evaluation times. The only significant difference was between 90 degrees PBWS and the control subgroup irrespective of the vessel factor in 24 hours. Histologic examination supported absence of thrombosis, as suggested by surgical examination. This may show that small-sized arteries are more inclined to thrombosis compared with larger ones and the thrombosis risk increases as the inadvertent back-wall stitch is more centrally located. Contrary to general notion that the inadvertent back-wall stitch causes immediate thrombosis, thromboses later than 1 hour, and even patent anastomoses in 24 hours, were observed in femoral and carotid artery groups. This study suggests that the inadvertent back-wall stitch should also be considered as a possible cause of late anastomotic problems.
    No preview · Article · Dec 2005 · Annals of Plastic Surgery
  • Cağri Savaş · Meltem Ozgüner · Faruk Ozgüner · Namik Delibaş
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    ABSTRACT: Unilateral testicular torsion can cause histologic damage, consisting of aspermatogenesis and tubular atrophy, in the contralateral testis human chorionic gonadotropin (HCG) treatment is widely used in undescended testis, and has been shown to improve histomorphometric alterations beside the testicular descent. However, the role of HCG in testicular torsion has not been investigated before. Therefore, this experimental study was conducted to evaluate the effects of HCG treatment on contralateral testicular histology and function in unilateral testicular torsion. Forty adult male Wistar rats were randomized into 4 groups: SHAM, SHAM+HCG, TORSION, and TORSION+HCG. Torsion was created by twisting the righ testis 720 degrees and maintained by fixing it to the scrotum. HCG treatment started 24 hours after the torsion at a dose of 100 IU/kg, twice weekly for three weeks. Left orchiectomy was performed one month after the torsion and removed testes were immersed in Bouin's fixative for histopathological evaluation. Mean seminiferous tubule diameter (MSTD) was measured and Johnsen's score was calculated. Blood samples were taken for assaying serum testosteron level. Unilateral testicular torsion resulted in a significant decrease in spermatogenesis and MSTD on the contralateral side. Serum testosteron level was also reduced. HCG treatment improved these parameters in the contralateral 'untwisted' testis beside the serum testosteron. Our data demonstrates that unilateral testicular torsion adversely effects its counterpart. HCG treatment improves contralateral histomorphometric alterations and serum testosteron in unilateral torsion.
    No preview · Article · Feb 2003 · International Urology and Nephrology