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Biomedical subjects

Muammer Kendirci

Publications and source records attributed to Muammer Kendirci.

At least 19 recordsLinked to original sources
PubMed2007

The learning curve in the training of percutaneous nephrolithotomy.

OBJECTIVES: To investigate the learning curve in the training of percutaneous nephrolithotomy (PCNL). METHODS: A total of 104 PCNL cases were included in this evaluation to define the learning curve of a surgeon with no previous experience at performing solo PCNL. Two parameters of expertise were reviewed, namely the operation and fluoroscopic screening times. The operation time was calculated as the beginning of access with the needle until the nephrostomy tube was placed and secured. PCNL procedures were analyzed in seven sets of 15 cases regarding the operation and fluoroscopy times, stone size, stone clearance rate, blood transfusion rate, and estimated blood loss. RESULTS: The mean operation time was 2.4 h for the first 15 patients. It decreased to a mean of 1.5 h for cases 46 through 60. No further decrease in the operation time was observed after case 60. The fluoroscopic screening time was a peak of 17.5 min in the first 15 cases, whereas it dropped to a mean of 8.9 min for cases 46 through 60. The decline in the mean fluoroscopy screening time continued in cases 61 to 104, but the decline was not significant. There was no significant difference in stone size, stone clearance rate, blood transfusion rate, and estimated blood loss among each set of cases. CONCLUSIONS: This study suggests that the surgical competence in PCNL can be reached after 60 cases. PCNL and fluoroscopy times drop to a steady-state level after performing 60 procedures.

Clinical Competence↗
PubMed2006

Mesenchymal stem cells alone or ex vivo gene modified with endothelial nitric oxide synthase reverse age-associated erectile dysfunction.

Mesenchymal stem cells (MSCs) can be used in adult stem cell-based gene therapy for vascular diseases. To test the hypothesis that MSCs alone or endothelial nitric oxide synthase (eNOS)-modified MSCs can be used for treatment of erectile dysfunction (ED), syngeneic rat MSCs (rMSCs) were isolated, ex vivo expanded, transduced with adenovirus containing eNOS, and injected into the penis of aged rats. Histological analysis demonstrated that rMSCs survived for at least 21 days in corporal tissue after intracavernous injection, and an inflammatory response was not induced. Intracavernous administration of eNOS-modified rMSCs improved the erectile response in aged rats at 7 and 21 days after injection. The increase in erectile function was associated with increased eNOS protein, NOS activity, and cGMP levels. rMSCs alone increased erectile function of aged rats at day 21, but not at day 7, with the transplanted cells exhibiting positive immunostaining for several endothelial and smooth muscle cell markers. This change in rMSC phenotype was accompanied by upregulation of penile eNOS protein expression/activity and elevated cGMP levels. These findings demonstrate that an adenovirus can be used to transduce ex vivo expanded rMSCs to express eNOS and that eNOS-modified rMSCs improve erectile function in the aged rat. Intracavernous injection of unmodified wildtype rMSCs improved erectile function 21 days after injection through mechanisms involving improved endothelium-derived NO/cGMP signaling and rMSC differentiation into penile cells expressing endothelial and smooth muscle markers. These data highlight the potential clinical use of adult stem cell-based therapy for the treatment of ED.

Aging↗
PubMed2006

Gene therapy for erectile dysfunction: fact or fiction?

OBJECTIVES: Erectile dysfunction (ED) is a major health problem that seriously affects the quality of life of patients and their partners. Although all three selective phosphodiesterase type 5 inhibitors (PDE5-Is) are effective in the majority of ED cases, PDE5-I therapy is less efficacious in some hard-to-treat populations (diabetics, men after radical prostatectomy), prompting the development of new approaches, including gene therapy strategies for ED. METHODS: Gene therapy approaches are discussed in terms of the possible role of gene therapy for the treatment of ED, potential targets for gene transfer, vectors to carry targeted genes, and gene strategies for ED in certain disease states, such as diabetes, ageing, arterial and venogenic insufficiency, and cavernous nerve injury. RESULTS: The penis is a convenient tissue target for gene therapy because of its external location and accessibility, the ubiquity of endothelial-lined spaces, and low level of blood flow, especially in the flaccid state. Gene therapy approaches have focused on a number of signaling pathways that are crucial for penile erection, such as nitric oxide/cyclic guanosine monophosphate, RhoA/Rho-kinase, growth factors, ion channels, peptides, and control of oxidative stress. CONCLUSIONS: The need for effective ED therapies in difficult-to-treat patients has encouraged investigators to seek novel modalities for the treatment of ED. Recent preclinical and clinical trials have demonstrated that gene therapy strategies may be feasible for these purposes.

Endothelium, Vascular↗
PubMed2006

Single stage Fowler-Stephens orchidopexy: a preferred alternative in the treatment of nonpalpable testes.

In this present study we aimed to discuss the surgical efficacy of single stage Fowler-Stephens orchidopexy (FSO) technique, with an emphasis on its practical and logical application that may be kept in mind during a standard orchidopexy procedure. Twenty-two children have undergone a single stage FSO procedure for nonpalpable testes during the last 9 years in our department. Surgical procedure was initiated with a standard inguinal oblique incision keeping in mind that depending on the position and the anatomic features of the testes a FSO method might be needed. While an excellent result was defined as a testis with good scrotal position, size and adequate blood flow on Doppler sonogram, acceptable result was a palpably normal sized testis in a high scrotal position with adequate blood supply and lastly an unacceptable result was the atrophy of the testis with compromised blood supply. During regular follow-up visits although some cases revealed testicular atrophy; long-term examination (12 months) did show that majority of the testes maintained their normal position and tissue consistency (21/24, 87.5%). Due to the necessity of surgical approach either in the evaluation or the treatment of nonpalpable testes in most cases along with the unsatisfactory data of the time consuming and invasive radiological procedures; we believe that a classical orchidopexy approach together with further single stage FSO will be a rational and satisfactory algorithm in the majority of such cases.

Child, Preschool↗
PubMed2006

Evaluation of bone mineral density after ileocystoplasty in children with and without myelomeningocele.

We evaluated the bone mineral density (BMD) after ileal augmentation cystoplasty in a group of children with and without myelomeningocele. Between 1996 and 2003, eight patients with neurogenic bladder and seven patients with non-neurogenic bladder underwent augmentation ileocystoplasty. Preoperative and postoperative serum creatinine and electrolytes were measured. All patients underwent clinical evaluation, supine height measurement, blood gas analysis, and BMD measurement using a dual energy X-ray absorptiometry (DEXA) postoperatively. BMD was measured at L1-L4 and femoral neck, and compared to age- and sex-matched population. Follow-up time was calculated from the day of surgery to the day of DEXA performance. A total of eight boys and seven girls with the mean age of 10.2 +/- 4.1 years were evaluated with respect to BMD measurement. Mean age was 9.8 years in neurogenic group and 10.5 in non-neurogenic group. Mean follow-up was 728 and 616 days in neurogenic and non-neurogenic groups, respectively. There were no significant differences between ages, follow-up times, preoperative and postoperative creatinine levels, pH and bicarbonate values, and supine heights. Mean BMD at L1-L4 was 55.7% in neurogenic group and 83.8% in non-neurogenic group. There was a statistically significant difference between the two groups (P = 0.02). Mean BMD at femoral neck was 72% in neurogenic group and 86.2% in non-neurogenic group. The difference was also statistically significant (P = 0.028). After augmentation ileocystoplasty, the BMD in early postoperative period of patients with myelomeningocele is lower than the patients with non-neurogenic neurogenic bladder, which have the same clinical characteristics except the neurologic pathology. In the light of our findings and the reported literature data as well, we may claim that BMD decrease after augmentation ileocystoplasty depends more on the underlying neurologic pathology and its locomotor consequences rather than the enterocystoplasty itself.

Absorptiometry, Photon↗
PubMed2006

Synchronous prosthetic implantation through a transscrotal incision: an outcome analysis.

PURPOSE: The ease of the transscrotal approach for penile prosthesis implantation and the proximity of the urethra has allowed the evolution of a new strategy for dual implantation of an AUS and IPP at a single setting. Concerns regarding increased infection rates and poor outcomes have prevented widespread acceptance of this simultaneous implantation technique. A multi-institutional evaluation of dual prosthesis implantation was performed to determine the overall efficacy, safety and long-term success of this innovative approach. MATERIALS AND METHODS: We performed a multi-institutional, retrospective analysis in patients with 2 urological prostheses (AUS and IPP). Only patients undergoing dual implantation via a single transscrotal technique were included for evaluation. Comorbidities, infection rates, and intraoperative and postoperative complications were recorded. RESULTS: A total of 22 men underwent AUS and IPP device implantation between 2000 and 2003 in a synchronous manner. Mean followup was 17 months. Complications were urethral erosion in 2 patients (9%) and reservoir migration in 2 (9%), of whom 1 underwent revision. Importantly no patient experienced a prosthetic infection postoperatively. The overall revision rate was 14%, due to urethral erosion of the AUS in 2 patients and reservoir migration in 1. All patients reported urinary leakage requiring 1 pad daily or less. CONCLUSIONS: Our initial intermediate followup in patients who underwent synchronous dual prosthetic implantation was favorable. The inherent advantage of a single anesthetic event and a single transscrotal incision should encourage widespread acceptance of this technique.

Aged↗
PubMed2006

Single-blind, multicenter, placebo controlled, parallel study to assess the safety and efficacy of intralesional interferon alpha-2B for minimally invasive treatment for Peyronie's disease.

PURPOSE: We investigated the efficacy and safety of intralesional interferon alpha-2b for the treatment of Peyronie's disease. MATERIALS AND METHODS: A total of 117 consecutive patients with a mean age of 55.1 years who had Peyronie's disease were enrolled in a single-blind, multicenter, placebo controlled, parallel study to determine the efficacy and safety of intralesional interferon alpha-2b therapy (Schering, Kenilworth, New Jersey), including 62 who received placebo and 55 who received interferon alpha-2b. Saline (10 ml) in controls and interferon alpha-2b (5 x 10(6) U) were administered biweekly for 12 weeks. Each patient was evaluated for penile curvature, plaque size and density, penile pain, erectile function and penile hemodynamics before and after study completion. Improvement in these parameters was statistically compared between the groups. RESULTS: A total of 53 patients in the control arm and 50 in the interferon alpha-2b arm completed the study. Improvement in penile curvature, plaque size and density, and pain resolution was significantly greater in patients treated with interferon alpha-2b vs placebo. The increase in mean International Index of Erectile Function scores was not significantly different between the groups. Penile blood flow improvement was observed in interferon alpha-2b treated patients but not in those who received placebo. The decrease in the number of penile vascular pathologies was significantly higher in interferon alpha-2b cases. Side effects, mostly flu-like symptoms, which were frequently noted in patients on interferon alpha-2b, were mild to moderate in degree and of short duration. CONCLUSIONS: This single-blind, multicenter, placebo controlled, parallel study demonstrates that intralesional interferon alpha-2b at a dose of 5 x 10(6) units biweekly for 12 weeks is effective and safe as minimally invasive therapy for Peyronie's disease.

Adult↗
PubMed2006

Update on erectile dysfunction in prostate cancer patients.

PURPOSE OF REVIEW: Evolution in the management of prostate cancer includes increased attention being paid to patient quality of life after treatment, specifically with issues related to sexual function. Erectile dysfunction is one of the major concerns of patients undergoing treatment for prostate cancer. There are several recognized factors that determine the postoperative incidence of erectile difficulties, including patient age, degree of cavernosal nerve sparing during surgery, cancer stage, and associated vascular comorbidities. Early initiation of rehabilitation protocols after radical prostatectomy has been advocated to promote the speed and degree of recovery of erectile function. The aim of this communication is to review recent initiatives in erectile dysfunction restoration after prostate cancer therapy. RECENT FINDINGS: In recognition of the neurogenic basis of erectile dysfunction after radical prostatectomy, new strategies have been devised to initiate the rehabilitation process. Type 5 phosphodiesterase inhibitors, vacuum erection devices, and intracavernosal and intraurethral application of vasoactive agents have all been reported in a positive light in recent studies. Developments in cavernous nerve graft interposition procedures, perioperative neuroprotection measures, and postoperative neurotrophic treatments aim to preserve prostate cancer patients' qualities of life. SUMMARY: Data generated from a number of clinical investigations document that pharmacologic rehabilitation programs provide a higher rate of recovery of erectile function following radical prostatectomy. Both intracavernosal and intraurethral applications of vasoactive agents and vacuum devices can speed the recovery period for return of erectile function. Various neuroprotective and neurotrophic approaches are thought to provide integral roles for the maintenance of sexual function in men undergoing prostate cancer therapy.

Animals↗
PubMed2006

Management of sildenafil treatment failures.

PURPOSE OF REVIEW: Although oral type 5 phosphodiesterase inhibitors are considered as first-line therapy for the majority of causes of erectile dysfunction, because of their high efficacy, ease of use, and acceptable safety profile, there are some who fail to respond, mainly because of end-organ failure. This communication reviews the management of sildenafil failures in light of recent advances. RECENT FINDINGS: Sildenafil failures can be attributed to either lack of efficacy or side effects; issues may involve the physician, patient, and his partner. Physicians may contribute to sildenafil failure and discontinuation because of inadequate instructions, lack of adequate follow-up, suboptimal dosing, lack of adequate trial, and insufficient clarification about safety issues. Studies have demonstrated that progression of endothelial dysfunction and diminished cavernosal smooth-muscle content are recognized organic factors which cause end-organ dysfunction and ultimately treatment failure. SUMMARY: Proper counseling, medication optimization, and modifying associated risk factors can provide success in men who had initially failed sildenafil therapy for erectile dysfunction. Other treatment modalities that may be considered when sildenafil failure occurs include vacuum devices, intraurethral, and intracavernosal administration of vasoactive drugs alone or combined with sildenafil. Penile prosthesis implantation is considered as a last resort, if all first-line and second-line therapies fail.

Counseling↗
PubMed2006

Accessory scrotum with multiple skeletal abnormalities.

Accessory scrotum is very uncommon. Here we report a 5-year old Caucasian boy presenting with an accessory scrotum localized to the left side of the pubic area. The penis and the primary scrotum were completely normal, containing two dependent testicles. On the right side of the body there was type B proximal femoral focal deficiency and there was also diastasis of the symphisis pubis. As observed in this case, abnormalities of two different embryological organ systems (accessory labioscrotal fold and proximal femoral focal deficiency) may occur concurrently at the same intrauterine time point as part of an overall embryologic mesenchymal disorder.

Abnormalities, Multiple↗
PubMed2006

The breakdown of preformed advanced glycation end products reverses erectile dysfunction in streptozotocin-induced diabetic rats: preventive versus curative treatment.

OBJECTIVES: Accumulation of advanced glycation end products (AGEs) has been linked to many of the complications of diabetes mellitus, including erectile dysfunction (ED). Furthermore, it has been demonstrated that inhibitors of AGE formation, such as aminoguanidine, can prevent ED in diabetic animals. However, it is unknown whether late administration of a putative cross-link breaker, ALT-711, can reverse diabetic ED. We therefore compared ALT-711 and aminoguanidine in their ability to reverse ED in diabetic rats. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly divided into four groups: (i) age-matched controls; (ii) streptozotocin (STZ)-induced diabetic rats (60 mg/kg; intraperitoneal injection); (iii) STZ diabetic rats treated with ALT-711 (3 mg/kg/day, intraperitoneal injection); and (iv) STZ diabetic rats treated with aminoguanidine (1 gm/L in drinking water) during the final 6 weeks of 12 weeks of induced diabetes. At the end of 12 weeks, erectile response to cavernous nerve stimulation (CNS) was determined. Neuronal nitric oxide synthase (nNOS) contents were measured in all penises, and AGE levels were determined both in penile tissues and in serum samples. RESULTS: Erectile responses to CNS and penile nNOS protein content were significantly reduced, while AGE levels were elevated in the penises and serum of untreated diabetic animals. Treatment with ALT-711, but not with aminoguanidine, reversed ED and nNOS depletion and reduced serum and penile tissue AGE levels. CONCLUSIONS: These results suggest that cross-link breakers, such as ALT-711, are the optimal therapeutic approach, compared with treatment with inhibitors of AGE formation, in the reversal of diabetes-related ED.

Animals↗
PubMed2006

Udenafil, a long-acting PDE5 inhibitor for erectile dysfunction.

Udenafil is an oral PDE5 inhibitor that is currently available in South Korea for the treatment of erectile dysfunction (ED). Phase II clinical data presented at the 11th World Congress of the International Society for the Sexual and Impotence Research showed that in men with mild-to-severe ED, the drug produced a significant improvement in erectile function after 12 weeks of treatment. Udenafil has been reported as being well tolerated, although in August 2005, the Korean Food & Drug Administration had demanded further details regarding the presence of carcinogenic substances in the drug. A phase IIa clinical trial for ED is currently underway in the US, and phase III trials are planned for 2006.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2005

Gene therapy for erectile dysfunction.

The past decade has seen an explosion of new information on the physiology of penile erection, pathophysiology of erectile dysfunction (ED), and development of new oral agents (e.g., three PDE5 inhibitors) to manage ED. Although all three selective PDE5 inhibitors are effective in the majority of ED cases, these oral medications have failed in certain disease states, such as diabetic ED, postprostatectomy ED, and severe veno-occlusive dysfunction. Only about 50% to 60% of these cases benefit from PDE5 inhibitor therapy, prompting the development of new approaches, including gene-based therapies for the treatment of ED. The penis is a convenient tissue target for gene therapy because of its external location and accessibility, the ubiquity of endothelial lined spaces, and low level of blood flow, especially in the flaccid state. Initially, gene therapy has been reserved for the treatment of life-threatening disorders including cancer, hereditary and acquired diseases. However, gene therapy is an attractive therapeutic possibility for the treatment of ED. Evolution of nitric oxide (NO), a small gaseous, lipophilic signaling molecule that is produced by nitric oxide synthase (NOS) activates guanylate cyclase (GC), resulting in increased cyclic guanosine monophosphate (cGMP) production, plays a significant role in our understanding of cavernosal smooth muscle physiology. Many gene therapy strategies have focused on the NO/GS/cGMP pathway. All three NOS isoforms, endothelial NOS (eNOS), neuronal NOS (nNOS), and iNOS have been used for gene therapy in order to modulate erectile response. Various viral and nonviral vectors have been used to date for the transfer of genetic material to the target cell or tissues with various degrees of success. Recently, second generation or "gutless" (helper-dependent) adenovirus vectors have been developed in order to reduce cellular toxicity and immune response, while increasing efficient gene therapy. Varieties of other gene therapy trials have also been undertaken for the treatment of ED and are the focus of this review.

Brain-Derived Neurotrophic Factor↗
PubMed2005

The impact of vascular risk factors on erectile function.

The main cause of erectile dysfunction is organic in nature, with vascular etiologies being the most common risk factors. The incidence of erectile dysfunction increases with the number of vascular comorbidities such as hypertension, diabetes, hyperlipidemia, smoking and atherosclerosis. The earliest signal of endothelial damage in men with vascular risk factors is the manifestation of erectile dysfunction. The penis is a barometer of the body's endothelial function, so it is reasonable then to correlate vascular pathologies as direct causes of erectile dysfunction. Moreover, erectile dysfunction may be the first clinical presentation of any of these comorbidities, with the vascular endothelium playing a pivotal role in regulating vascular homeostasis of the corpora cavernosa. This article addresses the impact of vascular risk factors on erectile function based on current evidence.

Diabetes Mellitus↗
PubMed2005

Central nervous system agents in the treatment of erectile dysfunction.

In the last two decades, a better understanding of the mechanisms governing erectile function and the pathophysiologies underlying erectile dysfunction (ED) have led re-searchers to investigate novel treatment concepts. Selective type-5 phosphodiesterase inhibitors are recommended as first-line therapy because of their high efficacy, but 30% to 40% of patients who have ED do not respond adequately to these agents and require alternative methods. The central nervous system plays a fundamental role in sexual behavior. Animal models have advanced our understanding of the neuroanatomic and neuropharmacologic basis of centrally induced penile erections. Clinical research with apomorphine has demonstrated efficacy in men who have a range of ED. Recent interest has focused on other centrally acting agents for ED treatment, including the melanocortin receptor agonists.

Apomorphine↗
PubMed2005

Urogenital surgery of the 15th century in Anatolia.

PURPOSE: We examined the urological procedures of the 15th century covered in the surgery textbook, Cerrahiyyetu'l Haniyye. MATERIALS AND METHODS: Three copies of the surgery textbook, Cerrahiyyetu'l Haniyye (Sultan's Surgery), by Serefeddin Sabuncuoglu, who lived in Turkey between 1385 and 1470, were evaluated. The colorfully miniaturized and illustrated textbook, written 536 years ago, covers a number of surgical disciplines, including urology. We evaluated urological sections with regard to the type of procedures, definitions and approaches for certain diseases and surgical tools used for urological operations. RESULTS: The textbook reviews the surgical treatment of urological conditions such as varicocele, hydrocele, hermaphroditism, imperforated urinary meatus, meatal stenosis, hypospadias, penile and scrotal lesions, and circumcision techniques. It includes definitions of diseases, etiologies and surgical therapies, and describes surgical instruments. The author also illustrated surgical approaches and instruments. CONCLUSIONS: A treasure trove of surgical knowledge, Cerrahiyyetu'l Haniyye has enlightened urologists from the 15th century to the present day.

Female↗