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Dive into the research topics where Yasar Ozgok is active.

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Featured researches published by Yasar Ozgok.


BJUI | 2013

Optimization of spermatogenesis-regulating hormones in patients with non-obstructive azoospermia and its impact on sperm retrieval: A multicentre study

Alayman Hussein; Yasar Ozgok; Lawrence S. Ross; Pravin Rao; Craig Niederberger

Study Type – Therapy (outcomes)


International Journal of Urology | 2000

Use of bladder mucosal graft for urethral reconstruction

Yasar Ozgok; M. Özgür Tan; Mete Kilciler; Lütfü Tahmaz; Doğan Erduran

Background: The ideal tissue for complex urethral reconstruction has yet to be determined, especially in patients with deficient preputium. The use of bladder mucosa as a free graft could be an alternative in these problem cases.


Urologia Internationalis | 2007

Clinical Significance of Platelet Count in Patients with Renal Cell Carcinoma

Fikret Erdemir; Mete Kilciler; Selahattin Bedir; Yasar Ozgok; Hidayet Coban; Koray Erten

Introduction: During the last decades numerous prognostic factors have been studied for predicting survival of renal cell carcinoma (RCC). Platelet count has previously been reported to correlate with prognosis in RCC. The aim of the this study was to evaluate the significance of thrombocytosis in determining prognosis in patients with localized RCC who underwent radical nephrectomy. Patients and Methods: The study included 118 consecutive patients. Patients were divided into a normal platelet count group (group 1) and a thrombocytosis group (group 2) according to the preoperative platelet count. Thrombocytosis was defined as a platelet count greater than 400,000/µl. The data about stage distribution, grade, tumor size, histological subtype, hemoglobin level, Body Mass Index (BMI), age, ECOG score, gender, and survival rate of tumors between these two groups were compared. Survival estimates were compared with the Kaplan-Meier method and multivariate analysis was performed using a Cox model. Results: The mean age of the patients was 61.4 years (range 30–78), and the mean follow-up period was 52.7 ± 19.6 months (range 9–96). Thrombocytosis was present in 23 patients (19.49%). Fourteen (60.86%) of 23 patients with thrombocytosis died of disease progression. Patients with thrombocytosis had a worse prognosis than patients without thrombocytosis (p = 0.001). Thrombocytosis was noted in 8 (10.81%) of 74 patients with stage pT1-pT2 disease and in 15 (34.09%) of 44 patients with stage pT3-pT4 disease (p = 0.004). In univariate analysis, platelet count was correlated with T stage, hemoglobin level, lymph node positivity, ECOG score, and tumor size. Controlling for established prognostic indicators of pathologic stage, tumor size, platelet count, and lymph positivity using Cox’s regression test, the difference in survival between the groups remained significant (p < 0.05). Conclusion: The platelet count can be considered a useful prognostic factor in patients with RCC who undergo radical nephrectomy.


International Journal of Urology | 2005

Endoscopic treatment of multiple prostatic calculi causing urinary retention

Selahattin Bedir; Mete Kilciler; Ozan Akay; Fikret Erdemir; Ali Avci; Yasar Ozgok

Abstract Although prostatic calculi are relatively common, the etiology of these stones is not clear. We report a case with multiple prostatic calculi causing urinary obstruction and a concomitant bladder stone. We treated these stones endoscopically. We found a lot of different sized stones endoscopically, some protruding into the urethra, some filling different cavities on the prostate. So these cavities suggest prostatic calculi may occur related to intraprostatic reflux in the congenital or acquired diverticulum of the prostatic tissue. In addition, the stone composition of the bladder and prostatic stones was the same. All of these results show that the origin of bladder and prostatic stones can be the same. This case also supports a theory of intraprostatic reflux and urine stasis.


European Urology | 2001

Diagnosis and Treatment of Ejaculatory Duct Obstruction in Male Infertility

Yasar Ozgok; M. Özgür Tan; Mete Kilciler; Lüfti Tahmaz; Yusuf Kibar

Objective: To discuss the diagnosis and treatment of ejaculatory duct obstruction in male infertility. Patients and Methods: Twenty–four males were treated for ejaculatory duct obstruction between 1994 and 1998 in our clinic. Patients’ age varied between 20 and 40 (mean=29). Ejaculatory duct obstruction was considered in patients with low to normal ejaculate volume, azoospermia or oligospermia, decreased motility, normal serum gonadotropin and testosterone levels, absent or low fructose in the ejaculate and evidence of obstruction on transrectal ultrasonography. The definitive diagnosis was made by the absence of efflux of methylene blue injected through the vas during cytoscopy. All the patients were subjected to transurethral resection of ejaculatory ducts and spermograms before and 3 months after resection were compared. Results: Before transurethral resection mean sperm count was 1.66×106/ml compared to 25.4×106/ml postoperatively. The difference was statistically significant (p=0.001). After the operation, 58.3% of the cases had improvement in sperm motility, and 62.5% had increased ejaculate volume. No significant complications occurred, and in only 1 (4.17%) patient, there was persistent hematuria. After a mean follow–up period of 9 (6–18) months, 6 (25%) pregnancies were noted. Conclusion: Although transurethral resection is an effective method for the treatment of ejaculatory duct obstruction, the pregnancy rate is low, which could be related to the hazardous effects of urinary reflux into ejaculatory ducts or functional abnormalities of seminal vesicles.


Urology | 2011

The Acute Effects of Increased Intra-abdominal Pressure on Testicular Tissue: An Experimental Study in Pigs

Mustafa Okan Istanbulluoglu; Mesut Piskin; Murat Zor; Asuman Celik; Aysegul Ozgok; Mutlu Ates; Hüseyin Üstün; Yasar Ozgok

OBJECTIVES To evaluate the acute effects of increased intra-abdominal pressure (IAP) on testicular germ cell apoptosis and the expressions of endothelial nitric oxide synthase (eNOS), inducible nitric-oxide synthase (iNOS), and Johnsons scores in testicular tissue. MATERIALS AND METHODS Twelve male pigs weighing 52 to 55 kg were divided into 2 groups as group 1 (n = 6; gasless [control]) and group 2 (n = 6; 20 mm Hg IAP with CO(2) pneumoperitoneum for 4 hours). In the second group, left laparoscopic nephrectomy was performed during the CO(2) insufflation period. The right testes of pigs were removed. Testicular germ cell apoptosis, expressions of eNOS and iNOS, and Johnsons scores were evaluated for each group. RESULTS The control group (group 1) exhibited low apoptotic cell level and low iNOS and eNOS level in testes. IAP (group 2) resulted in marked increases in germ cell apoptosis, eNOS, and iNOS compared with the control group (group 1) (P <.05). However, no significant difference was noted in Johnsons scores between the 2 groups (P >.05). Moreover, Leydig cell hyperplasia, congestion, and necrosis, which were not documented in the control group, were seen in the study group. CONCLUSIONS The purpose of the present study was to evaluate whether IAP could affect germ cell apoptosis and NOS concentrations in the testes after laparoscopic procedures in an animal model. In such an animal model simulating laparoscopic procedures, we demonstrated that high-pressure and long-lasting CO(2) insufflation cause testicular changes in the acute period.


International Journal of Urology | 2008

Nine cases of nonpalpable testicular mass: an incidental finding in a large scale ultrasonography survey

Ali Avci; Bulent Erol; Cenker Eken; Yasar Ozgok

Objectives:  Nonpalpable testicular masses are usually diagnosed during routine ultrasonography (US) examinations for other conditions. There are conflicting results on the final diagnosis and management of these lesions. In the present study we report the results of a large US series of 5104 patients on nonpalpable testicular masses and discuss the management of these patients.


Urologia Internationalis | 2006

Comparison of Ileal Conduit and Transureteroureterostomy with Ureterocutaneostomy Urinary Diversion

Mete Kilciler; Selahattin Bedir; Fikret Erdemir; Nazif Zeybek; Koray Erten; Yasar Ozgok

Introduction: We compare the postoperative early and late complications of patients who had undergone ileal conduit (IC) urinary diversion and transureteroureterostomy (TUU) with ureterocutaneostomy (UC) urinary diversion during the same interval and by the same surgeons. Materials and Methods: Between 1992 and 2004, we performed TUU with UC urinary diversion in 27 men and 7 women (group I) and ileal conduit urinary diversion in 57 men and 10 women (group II). The mean age of the TUU with UC diversion and the ileal conduit patients was 57 ± 11.2 (range 51–76) and 64 ± 12.6 (range 54–76) years, and the mean follow-up was 37 (range 14–52) and 56 (range 14–72) months, respectively. The 6F or 8F stents were used routinely. Results: Of 34 TUU with UC cases 8 (23.52%) had early postoperative complications and 2 (5.88%) had early reoperation rates, whereas 11 (16.42%) of 67 ileal conduit cases had early postoperative complications and 4 (5.97%) had early reoperation. The mean hospital stay was 7 (range 5–25 day) and 11 (range 7–34 day) days for each group, respectively. Of the TUU and UC cases, 6 (17.64%) had late complications and 3 had (8.82%) late reoperation, whereas 14 conduit cases (20.89%) had late complications and 6 had (8.9%) late reoperation. Early postoperative complications were defined as those that occurred before hospital discharge or within 30 days from the date of surgery and late complications were defined as those occurring greater than 30 days from the date of surgery as previously described. In group I, the mean operative time was 170 min (range 120–325) compared with 260 min (range 170–473) in group II. The mean blood loss in group I was 474 ml (range 250–1,400) and 589 ml (range 300–1,700) in group II (p > 0.05). Conclusions: Our results suggest that patients undergoing a TUU and UC diversion have no additional risk of reoperation and the TUU with UC urinary diversion is a safe procedure with postoperative early and late complications.


Urological Research | 2003

Increased vasoconstrictor reactivity and decreased endothelial function in high grade varicocele; functional and morphological study

Oguzhan Yildiz; Husamettin Gul; Yasar Ozgok; Onder Onguru; Mete Kilciler; Ahmet Aydin; Askin Isimer; A. Cetin Harmankaya

The pathophysiology of human varicocele is not fully understood. We investigated vasoconstrictor reactivity, endothelial function and morphological changes in different grades of varicocele to clarify the pathophysiology. Contractile responses to phenylephrine, norepinephrine, serotonin and histamine were determined in isolated human varicose spermatic veins using the organ bath technique. Endothelial function was tested with acetylcholine-induced relaxation after phenylephrine-induced precontraction in the absence and presence of nitric oxide synthase inhibitor, L-NAME, and cyclooxygenase inhibitor, indomethacin. The cyclic guanosine monophosphate (cGMP) level was measured in the spermatic vein and peripheral plasma. Morphological changes were evaluated with light microscopy. Phenylephrine, norepinephrine, serotonin and histamine induced concentration-dependent contractions. The maximum contractions for all of these agents except norepinephrine were significantly higher in grade III than grade I and II (P<0.05). The sensitivity to phenylephrine was significantly higher in grades II and III than in grade I (P<0.05). In the presence of L-NAME and indomethacin, the difference from respective control phenylephrine-induced contractions was higher in grade I and II than grade III. Acetylcholine did not induce stable relaxation but the level of cGMP, which is responsible for the vasorelaxant effect of NO, in veins was lower in grades II and III than grade I (P<0.05). Vessel wall thickness increased in grade II and dilatation developed in grade III when compared to grade I (P<0.05). Our findings suggest that endothelium produces less vasorelaxant which results in the more enhanced effects of vasoconstrictor substances in grade III, indicating that endothelial dysfunction develops at high grades of varicocele.


International Urology and Nephrology | 2007

Transitional cell carcinoma of the clitoris: direct implantation or metastasis

Eşref Oğuz Güven; Mete Kilciler; Selahattin Bedir; Ali Avci; Yasar Ozgok

Transitional cell carcinoma (TCC) of the bladder is the seventh most frequent cancer of women. The possible mechanisms of local tumor recurrence are seeding and multicentricity. Distant metastases are most frequently as a result of vascular or lymphatic spread and to a lesser extent by seeding of the tumor cells with urine or transurethral instrumentation. We report a clitoral metastasis of a TCC of the bladder, which is a very unexpected and extremely rare site for metatstasis and discuss whether the possible mechanism is vascular spreading or direct seeding. To our knowledge this is the third case in the literature.

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Mete Kilciler

Military Medical Academy

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Koray Erten

Military Medical Academy

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Onur Erdem

Military Medical Academy

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Ahmet Sayal

Military Medical Academy

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Fikret Erdemir

Gaziosmanpaşa University

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Doğan Erduran

Military Medical Academy

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Ayhan Savaser

Military Medical Academy

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