Ozkan Ozturk
University College London
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Publication
Featured researches published by Ozkan Ozturk.
Reproductive Biomedicine Online | 2007
M Appasamy; Shanthi Muttukrishna; Arnold Pizzey; Ozkan Ozturk; Nigel P. Groome; Paul Serhal; Eric Jauniaux
This study investigated the relationship between male reproductive hormones and sperm DNA damage and markers of oxidative stress in men undergoing infertility evaluation for male factor (n = 66) and non-male factor (n = 63) infertility. Semen samples were analysed for DNA fragmentation index (DFI). Serum samples were analysed for FSH, inhibin B, anti-Müllerian hormone (AMH), testosterone and total antioxidant capacity (TAC). Serum inhibin B was significantly lower in the male factor group compared with the non-male factor group. Inhibin B showed a positive correlation with sperm concentration and motility, and serum AMH showed a positive correlation with sperm concentration and semen volume. DFI was 3-fold higher in the male factor group and showed a negative correlation with sperm motility. Blood plasma TAC was negatively related to sperm concentration. The results confirm that AMH and inhibin B are markers of Sertoli cell function. Sperm DNA damage is moderately increased in male factor infertility, and is negatively associated with sperm motility. A negative association between antioxidant activity and sperm concentration suggests that even minimal oxidative stress may influence sperm concentration. However, there was no significant relationship between hormone concentrations, sperm DNA damage and total antioxidant capacity, suggesting other mechanisms for sperm dysfunction.
British Journal of Obstetrics and Gynaecology | 2001
Torvid Kiserud; Eric Jauniaux; Daniel West; Ozkan Ozturk; Mark A. Hanson
Objectives To determine fetal haemodynamic responses to hyperoxaemia and hypoxaemia in early pregnancy.
Reproductive Biomedicine Online | 2004
Ozkan Ozturk; Siladitya Bhattacharya; Ertan Saridogan; Eric Jauniaux; Allan Templeton
The objective of this study was to evaluate the role of uterine, endometrial and follicular blood flow in prediction of ongoing pregnancy after assisted conception. A prospective observational study was conducted on 53 women undergoing IVF treatment. Transvaginal colour and pulsed Doppler measurements were performed on the day that pituitary suppression was confirmed, on day 10 of ovarian stimulation and on the day prior to human chorionic gonadotrophin injection. On the last day of ovarian stimulation, blood flow in the ascending uterine artery of the women who would conceive was characterized by significantly lower pulsatility index values. Sub-endometrial vascular impedance was comparable in the pregnant and non-pregnant groups. There were no differences in the perifollicular vascularity between pregnant and non-pregnant women. The chance of achieving pregnancy predicted by uterine artery Doppler and perifollicular blood flow in women whose PI values were higher than 3.26 and 1.08 was very low, with a sensitivity of 1.00 and specificity of 0.59 and 0.82 respectively. The data provide evidence for an association between utero-ovarian perfusion and reproductive outcome following IVF treatment. Uterine and ovarian vascular impedance values identify those women whose pregnancy chances are significantly limited. Measures to decrease vascular impedance in such women might enhance pregnancy rates by improving embryo quality and uterine receptivity for implantation.
Journal of Obstetrics and Gynaecology | 2010
Banchhita Sahu; Ozkan Ozturk; Paul Serhal
Graesslin O, Dedecker F, Quereux C et al. 2005. Conservative treatment of ectopic pregnancy in a cesarean scar. Obstetrics and Gynecology 105:869–871. Jurkovic D, Hillaby K, Woelfer B et al. 2003. First trimester diagnosis and management of pregnancies implanted into the lower uterine segment caesarean section scar. Ultrasound Obstetrics and Gynecology 21:220–227. Katano K, Ukuta K, Matsubara H et al. 1999. A case of successful conservative chemotherapy for intramural pregnancy. Fertility and Sterility 72:744–746. Lee CL, Wang C, Chao A et al. 1999. Laparoscopic management of an ectopic pregnancy in a previous caesarean section scar. Human Reproduction 14:1234–1236. Marchiole P, Gorlero F, De Caro G. 2004. Intramural pregnancy embedded in a previous caesarean section scar treated conservatively. Ultrasound in Obstetrics and Gynecology 23:305– 309. Rotas MA, Haberman S, Levgur M. 2006. Cesarean scar ectopic pregnancies: etiology, diagnosis and management. Obstetrics and Gynecology 107:1373–1381. Shih JC. 2004. Cesarean scar pregnancy: diagnosis with three dimensional (3D) ultrasound and 3D power Doppler. Ultrasound in Obstetrics and Gynecology 23:306– 307. Valley MT, Pierce JG, Daniel TB et al. 1998. Cesarean scar pregnancy: imaging and treatment with conservative surgery. Obstetrics and Gynecology 91:838–840. Vial Y, Petignat P, Hohlfeld P. 2000. Pregnancy in a cesarean scar. Ultrasound in Obstetrics and Gynecology 16:592–593.
Reproductive Biomedicine Online | 2003
Jas Kalsi; Gulam Bahadur; Asif Muneer; Ozkan Ozturk; Nim Christopher; David J. Ralph; Suks Minhas
Erectile dysfunction (ED) affects the lives of approximately 150 million men worldwide. ED may be a cause of male sub-fertility in a significant proportion of patients. There is now an expanding armamentarium for the management of ED, including oral agents such as phosphodiesterase type 5 (PDE5) inhibitors. PDE5 inhibitors may also be useful in situations of temporary ED in couples undergoing IVF. Two novel PDE5 inhibitors have been commercially launched in the European Union in the first quarter of 2003. This article reviews the pharmacology and clinical efficacy of these new agents and their potential role in treating patients with male sub-fertility.
Reproductive Biomedicine Online | 2004
Ozkan Ozturk; Ertan Saridogan; Eric Jauniaux
Implantation in humans is a complex, closely regulated, highly selective and relatively poorly understood process. Humans have the highest rate of miscarriage in mammals and various pharmacological manipulations have been used to minimize pregnancy losses in both spontaneous pregnancies and pregnancies resulting from assisted reproduction technology. The widespread application of protocols using numerous drugs in assisted reproduction treatment has led to an increasing number of pregnancies exposed to these drugs. The vast majority of these protocols have been based on data from a few observational and often retrospective clinical studies. This paper reviews the recent literature on drug interventions in early pregnancy after assisted reproduction treatment. It is concluded that there are still numerous issues about the safety of most drugs for both the women and their fetus. In many cases, the benefits are theoretical and the possible long-term side-effects are untested. There is an urgent need for more epidemiological studies and randomized controlled trials to explore the use, efficacy and side-effects of both old and new drugs in early pregnancy after assisted reproduction treatment.
Cochrane Database of Systematic Reviews | 2013
Zabeena Pandian; Jane Marjoribanks; Ozkan Ozturk; Gamal I. Serour; Siladitya Bhattacharya
Human Reproduction | 2005
Gulam Bahadur; Ozkan Ozturk; Asif Muneer; R. Wafa; A. Ashraf; N. Jaman; S. Patel; A.W. Oyede; David J. Ralph
Human Reproduction | 2001
Ozkan Ozturk; Siladitya Bhattacharya; Allan Templeton
Archives of Gynecology and Obstetrics | 2008
Banchhita Sahu; Ozkan Ozturk; Massimo Ranierri; Paul Serhal