Stefan Propping

Characterization of different carbon nanotubes for the development of a mucoadhesive drug delivery system for intravesical treatment of bladder cancer

In order to increase the effectiveness of therapeutics for bladder carcinoma (BCa) treatment, alternative strategies for intravesical applications are needed. The use of carbon nanotubes (CNTs) as basis for a multifunctional drug transporter is a promising possibility to combine traditional chemotherapeutics with innovative therapeutic agents such as antisense oligodeoxynucleotides or small interfering RNA. In the current study four CNT types varying in length and diameter (CNT-1, CNT-2, CNT-3, CNT-4) were synthesized and then characterized with different spectroscopic techniques. Compared to the pristine CNT-1 and CNT-3, the shortened CNT-2 and CNT-4 exhibited more defects and lower aspect ratios. To analyze their mucoadhesive properties, CNTs were exposed to mouse bladders ex vivo by using Franz diffusion cells. All four tested CNT types were able to adhere to the urothelium with a mean covering area of 5-10%. In vitro studies on UM-UC-3 and EJ28 BCa cells were conducted to evaluate the toxic potential of these CNTs. Viability and cytotoxicity assays revealed that the shortened CNT-2 and CNT-4 induced stronger inhibitory effects on BCa cells than CNT-1 and CNT-3. In conclusion, CNT-1 and CNT-3 showed the most promising properties for further optimization of a multifunctional drug transporter.

Risk factors for incidental prostate cancer—who should not undergo vaporization of the prostate for benign prostate hyperplasia?†

Vaporization of the prostate (e.g., using laser devices) for treatment of benign prostatic hyperplasia does not allow for subsequent histological examination. Therefore, patients should be counseled about the risk of missing an incidental prostate cancer (incPCa). In this study the risk of an incPCa was determined based on all preoperative parameters.

Mucosa of human detrusor impairs contraction and β‐adrenoceptor‐mediated relaxation

To elucidate the impact of the mucosa on detrusor muscle function by investigating force of contraction under various stimulatory conditions and during subsequent relaxation using catecholamines.

β-Adrenoceptor-Mediated Relaxation of Carbachol-Pre-Contracted Mouse Detrusor

Aims: To study the β-adrenoceptor subtypes involved in the relaxation responses to (-)-isoprenaline in carbachol-pre-contracted (CCh) mouse detrusor muscle with intact and denuded mucosa. Methods: Isolated muscle strips from the urinary bladder of male C57BL6 mice or β2-adrenoceptor knockout mice were pre-contracted with CCh, 1 µM and relaxed with increasing concentrations of the β-adrenoceptor (β-AR) agonist (-)-isoprenaline and forskolin. For estimating the β-AR subtypes involved, subtype-selective receptor blockers were used, that is, CGP 20712A (β1-ARs), ICI 118,551 (β2-ARs), and L748,337 (β3-ARs). Results: Unlike in KCl-pre-contracted muscle, the mucosa did not affect the sensitivity of the relaxation response to (-)-isoprenaline in CCh-pre-contracted murine detrusor strips. Increasing concentrations of (-)-isoprenaline produced a biphasic concentration-relaxation response without any difference both during the presence and absence of mucosa. The relaxation fraction produced by low (-)-isoprenaline concentrations was mediated by β2-AR as evidenced by a shift of the concentration-response curve to higher concentrations with ICI 118,551, but not with CGP 20712A and L748,337, and by the absence of this fraction in β2-AR-KO mice. The relaxation response with low sensitivity to (-)-isoprenaline was not affected by any of the β-AR subtype-selective blockers and was the only response detected in detrusor strips from β2-AR-KO mice. Conclusions: In CCh-pre-contracted mouse detrusor, β2-ARs are responsible for the relaxation component with high sensitivity to (-)-isoprenaline as indicated by the conversion of a biphasic into a monophasic CRC with ICI 118,551 or by its absence in β2-AR KO mice. The mucosa does not impair relaxation under these conditions.

Pharmacological Modulation of Mucosa-Related Impairment of β-Adrenoceptor-Mediated Relaxation in Human Detrusor

Objectives: The mucosa of human detrusor strips impairs catecholamine-induced relaxation. In order to elucidate which signal transduction pathways are involved in this cross talk between the mucosa and detrusor, we have studied the effects of several pharmacological agonists and antagonists on noradrenaline-mediated relaxation in intact and mucosa-denuded detrusor strips. Patients and Methods: Strips of detrusor tissue were obtained from patients who had undergone cystectomy for bladder cancer and were set up for force measurement. KCl- or carbachol-precontracted strips were relaxed with increasing concentrations of noradrenaline in the absence and in the presence of nitric oxide synthase inhibitor, L-NAME; P2X-receptor antagonist, PPADS; ETA-receptor antagonist, BQ-123; ETB-receptor antagonist, BQ-788; cyclooxygenase inhibitor, diclofenac; AT1-receptor antagonist, candesartan; and NK1-receptor antagonist, L-703,606. Results: In intact strips, KCl-stimulated force was enhanced by all blockers; carbachol-stimulated force increased with L-703,606. In denuded strips, only L-NAME augmented the KCl-stimulated contraction. Noradrenaline relaxed the precontracted detrusor strips to a significantly larger extent and at lower concentrations in denuded than in intact strips. L-NAME, PPADS and BQ-123/BQ-788 had little effect on noradrenaline-induced relaxation, whereas diclofenac, candesartan and L-703,606 sensitized intact carbachol-stimulated detrusor strips to noradrenaline-induced relaxation. Conclusion: Inhibition of the noradrenaline-induced relaxation of precontracted human detrusor strips by the mucosa is attenuated by diclofenac, candesartan and L-703,606 suggesting the involvement of prostanoids, angiotensin and neurokinin pathways. Further experiments are required to unravel the exact mechanisms.

Level of education and mortality after radical prostatectomy

Estimating the risk of competing mortality is of importance in men with early prostate cancer to choose the most appropriate way of management and to avoid over- or under-treatment. In this study, we investigated the impact of the level of education in this context. The study sample consisted of 2630 patients with complete data on level of education (college, university degree, master craftsmen, comparable profession, or others), histopathological tumor stage (organ confined or extracapsular), lymph node status (negative or positive), and prostatectomy specimen Gleason score (<7, 7, or 8-10) who underwent radical prostatectomy between 1992 and 2007. Overall, prostate cancer-specific, competing, and second cancer-related mortalities were study endpoints. Cox proportional hazard models for competing risks were used to study combined effects of the variables on these endpoints. A higher level of education was independently associated with decreased overall mortality after radical prostatectomy (hazard ratio [HR]: 0.75, 95% confidence interval [95% CI]: 0.62-0.91, P = 0.0037). The mortality difference was attributable to decreased second cancer mortality (HR: 0.59, 95% CI: 0.40-0.85, P = 0.0052) and noncancer mortality (HR: 0.73, 95% CI: 0.55-0.98, P = 0.0345) but not to differences in prostate cancer-specific mortality (HR: 1.16, 95% CI: 0.79-1.69, P = 0.4536 in the full model). In conclusion, the level of education might serve as an independent prognostic parameter supplementary to age, comorbidity, and smoking status to estimate the risk of competing mortality and to choose optimal treatment for men with early prostate cancer who are candidates for radical prostatectomy.

Mucosa of murine detrusor impairs β2 -adrenoceptor-mediated relaxation.

To investigate the role of the mucosa in (−)‐isoprenaline‐induced relaxation of mouse detrusor muscle and to characterize the β‐adrenoceptor subtypes involved.

β-Adrenoceptor-mediated Relaxation of Urinary Bladder Muscle in β2-Adrenoceptor Knockout Mice.

Background and Objective: In order to characterize the β-adrenoceptor (AR) subtypes involved in agonist-stimulated relaxation of murine urinary bladder we studied the effects of (-)-isoprenaline and CL 316,243 on tonic contraction and spontaneous contractions in detrusor strips of wild-type (WT) and β2-AR knockout (β2-AR KO) mice. Materials and Methods: Urinary bladders were isolated from male WT and β2-AR KO mice. β-AR subtype expression was determined with quantitative real-time PCR. Intact muscle strips pre-contracted with KCl (40 mM) were exposed to cumulatively increasing concentrations of (-)-isoprenaline or β3-AR agonist CL 316,243 in the presence and absence of the subtype-selective β-AR blockers CGP 20712A (β1-ARs), ICI 118,551 (β2-ARs), and L748,337 (β3-ARs). Results: Quantitative real-time PCR confirmed lack of β2-AR expression in bladder tissue from β2-AR KO mice. In isolated detrusor strips, pre-contraction with KCl increased basal tone and enhanced spontaneous activity significantly more in β2-AR KO than in WT. (-)-Isoprenaline relaxed tonic tension and attenuated spontaneous activity with similar potency, but the concentrations required were two orders of magnitude higher in β2-AR KO than WT. The concentration-response curves (CRCs) for relaxation were not affected by CGP 20712A (300 nM), but were shifted to the right by ICI 118,551 (50 nM) and L748,337 (10 μM). The -logEC50 values for (-)-isoprenaline in WT and β2-AR KO tissue were 7.98 and 6.00, respectively, suggesting a large receptor reserve of β2-AR. (-)-CL 316,243 relaxed detrusor and attenuated spontaneous contractions from WT and β2-AR KO mice with a potency corresponding to the drug’s affinity for β3-AR. L743,337 shifted the CRCs to the right. Conclusion: Our findings in β2-AR KO mice suggest that there is a large receptor reserve for β2-AR in WT mice so that this β-AR subtype will mediate relaxation of tone and attenuation of spontaneous activity under physiological conditions. Nevertheless, upon removal of this reserve, β3-AR can also mediate murine detrusor relaxation.

Is the Post-Radical Prostatectomy Gleason Score a Valid Predictor of Mortality after Neoadjuvant Hormonal Treatment?

Purpose: To evaluate the validity of the Gleason score after neoadjuvant hormonal treatment as predictor of disease-specific mortality after radical prostatectomy. Patients and Methods: A total of 2,880 patients with a complete data set and a mean follow-up of 10.3 years were studied; 425 of them (15%) had a history of hormonal treatment prior to surgery. The cumulative incidence of deaths from prostate cancer was determined by univariate and multivariate competing risk analysis. Cox proportional hazard models for competing risks were used to study combined effects of the variables on prostate cancer-specific mortality. Results: A higher portion of specimens with a history of neoadjuvant hormonal treatment were assigned Gleason scores of 8-10 (28 vs. 17%, p < 0.0001). The mortality curves in the Gleason score strata <8 vs. 8-10 were at large congruent in patients with and without neoadjuvant hormonal treatment. In patients with neoadjuvant hormonal treatment, a Gleason score of 8-10 was an independent predictor of prostate cancer-specific mortality; the hazard ratio was, however, somewhat lower than in patients without neoadjuvant hormonal treatment. Conclusion: This study suggests that the prognostic value of the post-radical prostatectomy Gleason score is not meaningfully jeopardized by heterogeneous neoadjuvant hormonal treatment in a routine clinical setting.