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Dive into the research topics where Ozkan Ozturk is active.

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Featured researches published by Ozkan Ozturk.


Reproductive Biomedicine Online | 2007

Relationship between male reproductive hormones, sperm DNA damage and markers of oxidative stress in infertility

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

Circulatory responses to maternal hyperoxaemia and hypoxaemia assessed non-invasively in fetal sheep at 0.3-0.5 gestation in acute experiments

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

Role of utero–ovarian vascular impedance: predictor of ongoing pregnancy in an IVF–embryo transfer programme

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

Successful pregnancy in globozoospermia with severe oligoasthenospermia after ICSI

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

Novel PDE5 inhibitors for the treatment of male erectile dysfunction

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

Drug intervention in early pregnancy after assisted reproductive technology.

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

Number of embryos for transfer following in‐vitro fertilisation or intra‐cytoplasmic sperm injection

Zabeena Pandian; Jane Marjoribanks; Ozkan Ozturk; Gamal I. Serour; Siladitya Bhattacharya


Human Reproduction | 2005

Semen quality before and after gonadotoxic treatment

Gulam Bahadur; Ozkan Ozturk; Asif Muneer; R. Wafa; A. Ashraf; N. Jaman; S. Patel; A.W. Oyede; David J. Ralph


Human Reproduction | 2001

Avoiding multiple pregnancies in ART Evaluation and implementation of new strategies

Ozkan Ozturk; Siladitya Bhattacharya; Allan Templeton


Archives of Gynecology and Obstetrics | 2008

Comparison of oocyte quality and intracytoplasmic sperm injection outcome in women with isolated polycystic ovaries or polycystic ovarian syndrome

Banchhita Sahu; Ozkan Ozturk; Massimo Ranierri; Paul Serhal

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Eric Jauniaux

University College London

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Asif Muneer

University College Hospital

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David J. Ralph

University College Hospital

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Daniel West

University College London

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Mark A. Hanson

University of Southampton

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Paul Serhal

University College Hospital

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