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Urethral Resistance (urethral + resistance)
Selected AbstractsComputer-based endoscopic image-processing technology for endourology and laparoscopic surgeryINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2009Tatsuo Igarashi Abstract Endourology and laparoscopic surgery are evolving in accordance with developments in instrumentation and progress in surgical technique. Recent advances in computer and image-processing technology have enabled novel images to be created from conventional endoscopic and laparoscopic video images. Such technology harbors the potential to advance endourology and laparoscopic surgery by adding new value and function to the endoscope. The panoramic and three-dimensional images created by computer processing are two outstanding features that can address the shortcomings of conventional endoscopy and laparoscopy, such as narrow field of view, lack of depth cue, and discontinuous information. The wide panoramic images show an anatomical ,map' of the abdominal cavity and hollow organs with high brightness and resolution, as the images are collected from video images taken in a close-up manner. To assist in laparoscopic surgery, especially in suturing, a three-dimensional movie can be obtained by enhancing movement parallax using a conventional monocular laparoscope. In tubular organs such as the prostatic urethra, reconstruction of three-dimensional structure can be achieved, implying the possibility of a liquid dynamic model for assessing local urethral resistance in urination. Computer-based processing of endoscopic images will establish new tools for endourology and laparoscopic surgery in the near future. [source] ,1 -Adrenoceptor subtypes and lower urinary tract symptomsINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2008Debra A Schwinn Abstract: Benign prostatic hyperplasia (BPH) is a common cause of urinary outflow obstruction in aging men leading to lower urinary tract symptoms (LUTS). ,1 -Adrenoceptors (,1ARs) antagonists (blockers) have become a mainstay of LUTS treatment because they relax prostate smooth muscle and decrease urethral resistance, as well as relieving bladder LUTS symptoms. A review of key recent clinical trials suggests new insights into the role of specific ,1AR subtypes in the treatment of LUTS. [source] The role of angiotensin II in stress urinary incontinence: A rat modelNEUROUROLOGY AND URODYNAMICS, Issue 1 2007Hardeep Phull Abstract Aims Pharmacological treatment for stress urinary incontinence (SUI) is limited to the use of non-selective alpha-agonists, which are often ineffective. Non-adrenergic mechanisms have also been implicated in urethral closure, including angiotensin II (Ang-II), which has been demonstrated throughout the urinary tract. We investigate the role of Ang-II in urethral tone in a rat model of SUI. Methods Abdominal leak point pressure (ALPP) and retrograde urethral pressure profilometry (RLPP) were measured in 70 female virgin rats. Thirty rats underwent pudendal nerve injury (PNT), 30 had circumferential urethrolysis (U-Lys), and 10 had sham surgery. Rats received daily doses of Angiotensin Type 1 (AT-1) receptor inhibitor (20 mg/kg), Angiotensin Type 2 (AT-2) receptor antagonist (10 mg/kg), or Ang-II (2 mg/kg). Results Following U-Lys, RLPP and ALPP decreased from 21.4,±,2.0 and 39.2,±,3.3 mm Hg, to 13.1,±,1.5 and 21.6,±,1.9 mmHg, respectively (P<0.01). After PNT, RLPP, and ALPP decreased from 21.0,±,1.6 and 41.9,±,3.0 mmHg to 13.1,±,1.5 and 24.7,±,3.3 mmHg, respectively (P<0.01). AT-1 inhibitor caused significant decrease in RLPP and ALPP from 21.0,±,6.2 and 41.8,±,9.4 mmHg, to 12.0,±,3.8 and 25.6,±,6.6 mmHg, respectively (P<0.01). Likewise, AT-2 treatment reduced RLPP and ALPP from 21.4,±,6.3 and 40.1,±,1.7 mmHg, to 13.5,±,5.7 and 31.0,±,7.2 mmHg, respectively (P<0.01). Following surgery, Ang-II administration restored RLPP and ALPP to baseline presurgical values. Conclusions AT-1 and AT-2 receptor inhibition significantly lowers urethral resistance, comparable to either neurogenic or urethrolytic injury. Ang-II treatment restored urethral tone in rats with intrinsic sphincter dysfunction. Ang II appears to serve a functional role in the maintenance of urethral tone and stress continence. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source] Altered expression of thin filament-associated proteins in hypertrophied urinary bladder smooth muscleNEUROUROLOGY AND URODYNAMICS, Issue 1 2006Anita S. Mannikarottu Abstract Aims Obstruction of the urinary bladder outlet induces detrusor smooth muscle (DSM) hypertrophy. The goal of this study was to determine whether the composition of thin filament-associated proteins, known to play important roles in cytoskeletal structure and/or the regulation of contraction, is altered in DSM during hypertrophy. Methods DSM hypertrophy was induced in male rabbits by partial ligation of the urethra. Sham-operated rabbits served as a control. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR revealed a significant increase in the expression of mRNAs for basic (h1) calponin (CaP), and ,-isoform of tropomyosin (Tm) in hypertrophied DSM compared to controls. Western blotting and two-dimensional (2-D) gel electrophoresis showed enhanced expression of these proteins and also a significant increase in the expression of ,-non muscle and ,-smooth muscle actin in the DSM from obstructed bladders, while ,-actin remained constant. Results Enhanced expression of these proteins in the DSM from obstructed bladders was confirmed by immunofluorescence microscopy. Double immunostaining with Cap/Tm and ,/,-actin-specific antibodies showed co-localization of these proteins in myocytes. Colocalization of smooth muscle specific myosin and CaP to cytoplasmic filaments in cells dissociated from the hypertrophied DSM indicated that these cells are differentiated smooth muscle cells. Conclusions The change in the isoforms of actin, Cap, and Tm may be part of the molecular mechanism for bladder compensation in increased urethral resistance. Neurourol. Urodynam. © 2005 Wiley-Liss, Inc. [source] The effect of tamsulosin on the response of the rabbit bladder to partial outlet obstructionNEUROUROLOGY AND URODYNAMICS, Issue 1 2006Robert M. Levin Abstract Aim To determine if tamsulosin treatment prevents or decreases the incidence and severity of outlet obstruction-induced bladder dysfunction in rabbits. Materials and Methods Male New Zealand White rabbits were treated with tamsulosin or vehicle for 4 weeks with treatments initiated 1 week prior to sham or obstruction surgery. Cystometry was done on anesthetized rabbits 21 days after surgery. The bladders were then removed, weighed, and prepared for in vitro whole bladder studies. Responses to 32 Hz field stimulation (FS), carbachol, phenylephrine, and KCl were measured. Results Obstruction resulted in a significant increase in bladder weight, which was unchanged by tamsulosin treatment and a significant increase in micturition pressure in the vehicle-treated group but not in the tamsulosin-treated group. Compliance was significantly decreased in both obstructed groups. The vehicle-treated obstructed rabbits had a very sharp increase in intravesical pressure as the bladder reached capacity; this was not seen in the tamsulosin-treated obstructed rabbits. Tamsulosin did not change the pattern of modifications in contractile responses induced by bladder outlet obstruction. Conclusions In vitro responses of vehicle and tamsulosin-treated obstructed rabbit groups in this study were similar. A greater micturition pressure was found for the vehicle-treated obstructed group than for the tamsulosin-treated obstructed group, which was probably due to decreased urethral resistance in the latter. On a functional basis, the higher compliance at capacity and decreased micturition pressure in the tamsulosin-treated obstructed group would be considered beneficial for bladder function. Neurourol. Urodynam. © 2005 Wiley-Liss, Inc. [source] Urodynamic evaluation of the human bladder response tgo an increase in outlet resistanceNEUROUROLOGY AND URODYNAMICS, Issue 6 2002Jason D. Engel Abstract Aim. We prospectively evaluated the response of the human bladder to a chronic increase in urethral resistance according to the indices of pressure, volume flow rate, total (external) bladder work, and maximum and average detrusor power. Methods. Six men with incontinence after radical prostatectomy were evaluated urodynamically before and 3,6 months after undergoing a bulbourethral sling procedure. Results. None of the men suffered from significant obstructive or irritative voiding symptoms preoperatively. Urodynamic evaluation showed postoperative increases in both average detrusor pressure and pressure at maximum flow, but there were no significant changes in voided volume, void time, or postvoid residual urine volume. Maximum detrusor power, average detrusor power, and total (external) bladder work were all significantly increased. Conclusion. These data confirm that the human bladder possesses a functional reserve, which is elicited by an increase in urethral resistance. Neurourol. Urodynam. 21:524,528, 2002. © 2002 Wiley-Liss, Inc. [source] Comparative study of pressure-flow parametersNEUROUROLOGY AND URODYNAMICS, Issue 3 2002Lars M. Eri Abstract Methods for quantification of bladder outlet obstruction (BOO) are still controversial. Parameters such as detrusor opening pressure (pdet.open), maximum detrusor pressure (pdet.max), minimum voiding pressure (pdet.min.void), and detrusor pressure at maximum flow rate (Pdet.Qmax) separate obstructed from nonobstructed patients to some extent, but two nomograms, the Abrams-Griffiths nomogram and the linearized passive urethral resistance relation (LinPURR), are more accepted for this purpose, along with the urethral resistance algorithm. In this retrospective, methodologic study, we evaluated the properties of these parameters with regard to test-retest reproducibility and ability to detect a moderate (pharmacologic) and a pronounced (surgical) relief of bladder outlet obstruction. We studied the pressure-flow charts of 42 patients who underwent 24 weeks of androgen suppressive therapy, 42 corresponding patients who received placebo, and 30 patients who had prostate surgery. The patients performed repeat void pressure-flow examinations before and after treatment or placebo. The various parameters were compared. Among the bladder pressure parameters, Pdet.Qmax seemed to have some advantages, supporting the belief that it is the most relevant detrusor pressure parameter to include in nomograms to quantify BOO. In assessment of a large decrease in urethral resistance, such as after TURp, resistance parameters that are based on maximum flow rate as well as detrusor pressure are preferable. Neurourol. Urodynam. 21:186,193, 2002. © 2002 Wiley-Liss, Inc. [source] Treatment of incontinence after prostatectomy using a new minimally invasive device: adjustable continence therapyBJU INTERNATIONAL, Issue 4 2005Wilhelm A. Hübner OBJECTIVE To evaluate the safety and efficacy of a new minimally invasive urological implant for incontinence after prostatectomy. PATIENTS AND METHODS The adjustable continence therapy device (ProACTTM, Uromedica, Plymouth, MN, USA) consists of two balloons placed via a perineal approach bilaterally at the bladder neck in patients after prostatectomy. Titanium ports, attached via discrete tubing to each balloon, are placed in the scrotum, allowing for separate volume adjustments of the balloons at any time during and after surgery. Changes in a quality-of-life questionnaire (I-QoL), pad usage and a subjective continence grading score were assessed in 117 consecutive men after implanting the Pro-ACT, at baseline and at 1, 3, 6, 12 and 24 months. RESULTS After a mean (range) follow-up of 13 (3,54) months and with a mean of 3 (0,15) adjustments, 67% of men were dry, using at most one ,security' pad daily; 92% were significantly improved, and 8% showed no improvement. The I-QoL score improved from a median of 34.7 to 66.3 after 2 years (42 men; P <,0.001), the daily pad count decreased from a mean of 6 (1,24)/day to 1 (0,6)/day at 2 years (P < 0.001). Continence achieved at ,,6 months after implantation through incremental adjustment remained durable at ,,2 years in most patients. There were complications during and after surgery in 54 patients, mostly minor and decreasing with increasing expertise, primarily reflecting the development and refinement of the new surgical technique and its instrumentation. Re-implantation for complications was required in 32 patients, with a 75% success rate. CONCLUSIONS The ProACT peri-urethral prosthesis produces durable outcomes equivalent or better than other minimally invasive treatments for incontinence after prostatectomy. Its unique design allows for easy adjustment after surgery to achieve the desired urethral resistance, with no further surgical intervention, thus allowing for an optimum balance between voiding pressures and continence. The promising results reported here suggest that this may be an appropriate, effective and durable first-line treatment to offer men with stress urinary incontinence after prostatectomy. [source] | ||||||||||