Publications by authors named "Christian Stief"

Objective: To provide an overview on the current status of the long-term outcomes of instrumental treatment options for patients with lower urinary tract symptoms that are suggestive of bladder outlet obstruction.

Methods: Based on MEDLINE database searches, we performed a systematic review of the literature with a focus on peer-reviewed articles about surgical benign prostatic hyperplasia (BPH) therapy published between 2000 and 2005. Special emphasis was given to randomized controlled trials on long-term outcome with a minimum follow-up of five years.

View Article and Find Full Text PDF

Objectives: With the introduction of sildenafil citrate (Viagra), the concept of phosphodiesterase (PDE) inhibition has gained tremendous interest in the field of urology. Cyclic nucleotide second messengers cGMP and cAMP have been assumed to be involved in the control of the normal function of the prostate. The aim of the present study was to evaluate by means of immunohistochemistry the expression and distribution of some cAMP- and cGMP-PDE isoenzymes in the prostate.

View Article and Find Full Text PDF

Four surgical techniques for living donor nephrectomy were analyzed retrospectively in terms of perioperative outcome and early complication rate. A total of 182 donor nephrectomies including 69 open (OLDN), 14 fully laparoscopic (LDN), 34 hand-assisted laparoscopic (HLDN) and 65 retroperitoneoscopic (RLDN) nephrectomies were analyzed. There was a significant difference in mean operating time (OPT) between the OLDN (160 min) and RLDN (150 min) as compared to the LDN (212 min) and HLDN group (192 min) (P < 0.

View Article and Find Full Text PDF

Introduction: Advances in understanding of the biochemistry and physiology of penile erection have led to breakthroughs in pharmacotherapy of erectile dysfunction.

Aim: To provide recommendations/guidelines concerning state-of-the-art knowledge for the putative molecular and cellular mechanisms of action of centrally and peripherally acting drugs currently utilized in pharmacotherapy of erectile dysfunction.

Methods: An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees.

View Article and Find Full Text PDF

To date, it is widely accepted that several disorders of the male and female urogenital tract, such as erectile dysfunction, bladder overactivity, urinary stone disease and the benign prostatic syndrome, can be therapeutically approached by influencing the function of the smooth musculature of the respective organs. In order to achieve a pronounced drug effect without significant adverse events, especially on the cardiovascular system, a certain degree of tissue selectivity is mandatory. Selective intervention in intracellular pathways regulating smooth muscle tone has become a promising strategy to modulate tissue function.

View Article and Find Full Text PDF

Objectives: It has been well established that male erectile dysfunction is frequently associated with vascular diseases. The normal function of cavernous arteries is considered a prerequisite to maintain sufficient blood flow to the trabecular spaces in order to enable penile erection. Contractility of cavernous arteries is regulated by the peripheral autonomic nervous system and endogenous factors released from the endothelial cell layer.

View Article and Find Full Text PDF

Based on the increasing knowledge on both the physiology of penile erection and the pathophysiology of erectile dysfunction, selective phosphodiesterase (PDE) inhibitors have been successfully introduced in the oral treatment of male erectile dysfunction. Because of their central role in smooth muscle tone regulation, PDEs remain an attractive target for drug development in urology. Since the distribution and functional significance of PDE isoenzymes vary in different tissues, selective inhibitors of the isoenzymes have the potential to exert at least partially specific effects on the target tissue.

View Article and Find Full Text PDF

Bladder cancer is a frequent disease and represents the second most common genitourinary neoplasm. Although many aspects of the management of superficial bladder cancer are now well established, significant challenges remain, which influences patient outcome. Early detection and treatment of recurrent disease is required to optimize bladder preservation, reduce patient morbidity, and increase quality of life and survival.

View Article and Find Full Text PDF

Objectives: We retrospectively performed a comparative analysis of retroperitoneoscopic and open donor nephrectomy in terms of donor complications, as well as recipient complications and functional graft outcome.

Methods: A total of 134 donor nephrectomies including 69 open (ODN) and 65 retroperitoneoscopic (RDN) nephrectomies was analyzed retrospectively. Both groups were comparable in terms of age, body mass index (BMI), operating time (OPT), warm ischemia time (WIT) and blood loss.

View Article and Find Full Text PDF

Objective: To investigate the influence of commercially available vasoactive drugs on human cavernosal endothelial and fibroblastic cells in vitro, as although corporal fibrosis is a well known side-effect of intracavernosal injection therapy for erectile dysfunction, the possible detrimental effect of these agents on the endothelium lining the cavernosal vascular spaces is uncertain.

Materials And Methods: Cultured primary endothelial (13) and fibroblastic cells (12), obtained from potent patients undergoing penile surgery, were exposed to different physiological dilutions of prostaglandin E1 (PGE1), papaverine/phentolamine or the respective triple-mix of these agents for 30 min. Viable cells were counted and cell metabolic activity measured in these cultures 48 h after drug exposure.

View Article and Find Full Text PDF

Objectives: Primary cell cultures derived from the corpus cavernosum are frequently used as in vitro models to define cellular mechanisms involved in erectile function. However, previous studies often lack detailed isolation protocols or a precise characterisation of the culture composition excluding especially contaminating fibroblasts. This study aimed at critically analysing and reproducing reported isolation methods, as well as establishing new procedures to receive highly pure and morphologically differentiated endothelial, smooth muscle and fibroblastic cells derived from the human penis.

View Article and Find Full Text PDF

Metastatic renal cell carcinoma has a poor prognosis. Conventional therapies such as chemotherapy, radiation or hormonal treatment have hardly any effect on the progression of this disease. As renal cell carcinoma seems to be an immunogenic tumor, several immunotherapeutic approaches with different response rates have been developed since the early 1990s.

View Article and Find Full Text PDF

Objectives: To evaluate the distribution of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) phosphodiesterases (PDEs) in relation to nitric oxide synthase isoforms and vasoactive intestinal polypeptide (VIP) in specimens of the human vagina. Nitric oxide and VIP, mediating biologic signals through cGMP and cAMP, have been assumed to be involved in the control of vaginal smooth muscle.

Methods: Immunohistochemical techniques were applied to sectioned specimens of the human vaginal wall to evaluate the presence of the PDE isoenzymes 3, 4, 5, and 10 in relation to neuronal nitric oxide synthase (nNOS), endothelial NOS (eNOS), and VIP.

View Article and Find Full Text PDF

Objectives: Laparoscopic cryoablation has recently been proposed as a minimally invasive nephron-sparing treatment for selected patients. We report on our experience with a retroperitoneoscopic technique using multiple ultrathin cryoprobes.

Methods: Seven patients underwent retroperitoneoscopic renal cryoablation for solid renal masses.

View Article and Find Full Text PDF

Purpose: We generated a vascularized, autologous, reseeded bladder substitute and evaluated immediate vascularization and perfusion of the graft after implantation to the recipient organism in a porcine model.

Material And Methods: Acellular matrix was processed from porcine small bowel segments by subsequent mechanical, chemical and enzymatic decellularization, preserving the jejunal arteriovenous pedicles. In 2 separate steps the matrix was reseeded with primary bladder smooth muscle cells (SMCs) and urothelial cells (UCs), and its vascular structures were resurfaced with endothelial progenitor cells (EPCs).

View Article and Find Full Text PDF

Purpose: Men with lower urinary tract symptoms secondary to benign prostatic hyperplasia who are at high cardiopulmonary risk or on oral anticoagulation are often denied surgical treatment. Potassium-titanyl-phosphate (KTP) laser vaporization at 80 W is a novel, rapidly emerging technique that promises instant hemostatic tissue ablation. We evaluated the merits of this procedure in patients at high risk and those on long-term anticoagulation.

View Article and Find Full Text PDF

Objectives: To investigate the cytotoxic effect of prostaglandin E(1) (PGE(1)), a standard combination of papaverine/phentolamine, and a triple mixture of these agents on human cavernosal endothelial cells using a cell culture model. The endothelial layer of the corpus cavernosum plays an important role in signal transduction of penile erection and is directly exposed to vasoactive agents after intracavernous injection for erectile dysfunction.

Methods: Primary endothelial cells were obtained from the corpus cavernosum of 13 potent patients undergoing penile surgery.

View Article and Find Full Text PDF

Objectives: The aim of the present study was to generate a tissue engineered type of mechanically stable graft suitable for surgical replacement of the tunica albuginea penis.

Methods: Porcine fibroblasts isolated from open fascia biopsies were seeded on decellularized collagen matrices and then cultivated in a bioreactor under continuous multiaxial stress for up to 21 days (n=12). Static cultures without mechanical stress served as controls.

View Article and Find Full Text PDF

Nitric oxide (NO)/cyclic GMP (cGMP)-mediated mechanisms have a pivotal function in reducing the tone of the penile smooth musculature during normal erectile responses. The cyclic AMP (cAMP) signaling pathway is also involved in the adjustment of smooth muscle contractility, and suggestions for interactions between cGMP- and cAMP-mediated mechanisms have been presented. Using activators of the cGMP- or the cAMP-pathway, as well as inhibitors of protein kinase A (PKA; cAMP-dependent kinase) and protein kinase G (PKG; cGMP-dependent kinase), the present study was undertaken to further delineate the functional relation between these pathways in the penis.

View Article and Find Full Text PDF

Laparoscopic radical prostatectomy (LRPE) became the operative procedure of choice for patients with clinically localized prostate cancer in selected urologic centers around the world. Principal advantages are the minimal invasive nature of the procedure, a superior visualization of the operative field because of the magnification of the optical system, an exact and watertight anastomosis, the possibility of early catheter removal, and a potentially reduced amount of blood loss. Recent data show that oncologic outcome is not compromised by the minimal invasive nature of the procedure.

View Article and Find Full Text PDF

Despite the central and peripheral effects of androgens on the nervous system, the local effects of androgens in the corpus cavernosum penis and their importance for erectile function is still unclear. In this study corpus cavernosum biopsies of eight adult potent patients, aged 19-63 years, undergoing penile deviation surgery (group A) and 12 patients undergoing male-to-female transsexual surgery (group B) were immunostained for nuclear androgen and estrogen-alpha receptors. Additionally, primary corpus cavernosum endothelial cell cultures were obtained from six transsexual patients and exposed to testosterone, dihydrotestosterone, estradiol and progesterone likewise for 7 days.

View Article and Find Full Text PDF

Background: It has been speculated for more than 2 decades whether there is a significance of adrenal corticosteroids, such as cortisol, in the process of normal male sexual function, especially in the control of sexual arousal and the penile erectile tissue. However, only few in vivo studies have been carried out up until now on the effects of cortisol on human male sexual performance and penile erection. In order to evaluate further the role of cortisol in male sexual activity, the present study was conducted to detect serum levels of cortisol in the systemic and cavernous blood taken during different penile conditions from healthy males.

View Article and Find Full Text PDF

The promising clinical data on the use of the first orally active phosphodiesterase inhibitor sildenafil citrate (Viagra) for treatment of male erectile dysfunction have been accompanied by an increase in research activities on the physiology of the male erectile mechanism. This included both peripheral intracellular signal transduction in the corpus cavernosum as well as central brain and spinal cord pathways that control penile erection. This work provided the basis for the development and introduction of several new therapeutic modalities into the management of erectile dysfunction that is now offered to the patients.

View Article and Find Full Text PDF