Randy Vince

Effects of vesical and perfusion pressure on perfusate flow, and flow on vesical pressure, in the isolated perfused working pig bladder reveal a potential mechanism for the regulation of detrusor compliance

Although there is evidence that deficits in bladder blood flow negatively impact bladder function, the effects of vesical, and perfusion pressures on bladder perfusion (perfusate flow), and of perfusate flow on vesical pressure, remain poorly understood. The present study used the isolated perfused working pig bladder model to examine the relationships between blood flow, and vesical and perfusion pressures.

Surveillance Strategies for Neurogenic Lower Urinary Tract Dysfunction

Patients with neurogenic lower urinary tract dysfunction (NLUTD) experience significant morbidity and mortality due to urological complications including upper tract damage and bladder malignancy. This has led to increased surveillance in patients NLUTD. This article discusses the methods available for surveillance of patients with NLUTD and pulls information from the largest and most established organizations that have produced evidence-based surveillance guidelines for NLUTD. These organizations include the Paralyzed Veterans of America (PVA), US Department of Veterans Affairs, European Association of Urology (EAU), The NICE organization from the UK, and cites additional literature not been included in these documents.

Randomized trial of concentrated proanthocyanidins (PAC) for acute reduction of bacteriuria in male veterans with spinal cord injury utilizing clean intermittent catheterization

Study designThis study was a double-blind, placebo-controlled trial of a concentrated PACs compound (36 mg/capsule), in veterans with SCI and neurogenic lower urinary tract dysfunction (NLUTD) requiring intermittent catheterization (IC) over a 15-day period.ObjectivesThe objective of this study was to evaluate the acute effects of concentrated proanthocyanidins (PACs) in the cranberry supplement ellura® on bacteriuria, leukocyturia, and subjective urine quality in catheter-dependent veterans with SCI.SettingSpinal cord injury center (outpatient clinic and inpatient unit).MethodsParticipants with positive urine bacterial colonization (≥50 K CFU/ml) were randomized to once daily concentrated PACs or identical placebo and followed with daily (in-patients) or twice weekly (out-patients) urine cultures with colony forming units per milliliter (cfu/ml) range (bacteriuria), microscopic urine white blood cells per high-powered field (wbc/hpf) quantification (leukocyturia), and surveys assessing urine clarity, odor, color, sediment, and overall satisfaction. A repeated measure analysis of variance was used to compare treatment vs. control and evaluate serial trends.ResultsA total of 13 male participants (7 randomized to concentrated PACs, 6 to placebo) completed the trial. There was no significant decrease over the study period in colony forming units per milliliter (cfu/ml) or log(wbc/hpf) in the treatment vs. the control group. Patients receiving concentrated PACs rated the clarity, odor, color, sediment, and overall satisfaction of their urine as insignificantly improved compared to placebo.ConclusionsAcutely, there was no reduction of bacteriuria and pyuria or improvement in subjective urine quality for SCI patients treated with daily concentrated PACs.

Potential vascular mechanisms in an ex vivo functional pig bladder model

Chronic ischemia is a recognized factor in the pathophysiology of underactive bladder (UAB). Although relative ischemia (ie, low blood flow) is known to occur during filling, little is known regarding the pathophysiology that leads to UAB. Therefore, we developed an ex vivo functional porcine model to investigate the role of transient ischemia and whether autoregulation, a mechanism that maintains tissue oxygenation in certain vital organs, also exists in the bladder.

MP94-19 A POTENTIAL NOVEL MECHANISM FOR DETRUSOR UNDER-ACTIVITY MEDIATED BY MYOSIN LIGHT CHAIN PHOSPHORYLATION AND AMP-DEPENDENT KINASE

urine flow from internal vew of baldder neck. using by wireless capsule endoscopes (WCEs) for cystoscopy at voiding in vivo. METHODS: Experimental evaluation of capsule cystoscopy was performed in a 5-kg farm rabbits(n1⁄46). The capsule was inserted after incision of bladder. Images were continuously transmitted at a rate of four frames per second to a laptop computer and processed using proprietary software. Manipulation of the WCE within the bladder was performed using a set protocol. We measured the ability to deploy and manipulate the capsule within the bladder. Feasibility of capturing and retrieving images in real time was also assessed. We used air bubble(injection by syringe) and dye(intravenous administration of indigocarmine) as urine flow tracer. RESULTS: The WCE was efficiently deployed and manipulated within the bladder passively by manual. The entire bladder mucosa realtime image transmission and capture was visualized. The urine flow rotated clockwise from ventral to visceral at bladder neck during voiding. Fig.a): closed bladder neck before voiding, b)c) :air bubble rotated fom 12 to 3 at clock and d)sucked to internal urethra,no apparent of the air bubble. Fig(A) :the dye was visualized on closed bladder neck before voiding Fig(B) :when bladder neck begun to open, the dye visualized a vortex with rotation clockwise like crescent moom. CONCLUSIONS: By this device, urine flow could be visualized a vortex with rotation clockwise from ventral to visceral at the bladder neck mucosa during voiding.

MP63-06 CATEGORIZATION OF REAL-TIME SENSATION PATTERNS DURING URODYNAMICS

each one of the significant variables (p<0.05) in the logistic regression model. To conclude, we performed a ROC curve in order to determine the predictive ability of the score in relation to the presence of OAD. RESULTS: presence of OAD was evident in 210 women (29%). In the logistic regression analysis, independent predictors of OAD were micturition urgency, UUI, nicturia, absence of SUI symptoms, presence of diabetes, reduction of vaginal trophism and vesical capacity under 150 mL. The IDC diagnosis probability increases directly as the score raises (Score 0: 4% until Score 1⁄410: 88%). Sensitivity is 71% and specificity 72%. The area under the curve of OAB score was 0.784 (p>0.001). CONCLUSIONS: OAB score is a clinical tool that shows higher diagnostic accuracy than OAB symptoms alone when predicting overactive detrusor (OAD).

MP63-07 CHARACTERIZATION OF LOW AMPLITUDE RHYTHMIC CONTRACTIONS DURING URODYNAMICS

INTRODUCTION AND OBJECTIVES: Human detrusor smooth muscle (DSM) can exhibit low amplitude rhythmic contractions (LARC) which may contribute to overactive bladder (OAB) in some patients. The aim of this study was to develop an objective method to identify LARC during urodynamics (UD), categorize patients with significant LARC, and potentially begin to characterize a LARC-mediated OAB/detrusor overactivity subtype. METHODS: An algorithm was developed to analyze UD filling data in low volume (1st 410 seconds) and high volume (final 410s) regions. Fast Fourier Transform (FFT) analysis identified the frequency (F) in the 1-6 cycle/min range associated with the maximum amplitude of the vesical pressure (Pves) in each region (Fig 1). A patient-specific range of interest corresponding to F 0.5 cycles/min was determined. Pves and Pabd amplitudes were analyzed separately to identify both significant (higher than average) and independent (distinct from Pabd) Pves signals. To be significant, Pves amplitude must be > 1.35 standard deviations (SD) above average Pves amplitude. To be independent, the Pabd amplitude must be < 1.35 SD above the average Pabd amplitude. SD of 1.35 was chosen using an iterative process in 0.05 SD increments to identify the maximum number of significant and independent signals. RESULTS: This algorithm was used to retrospectively analyze 43 consecutive UD studies which included 25 (14 neurogenic, 11 idiopathic) with detrusor overactivity (58%). The average age of the entire group was 55 2 years and included 14 men and 29 women. FFT analysis identified a significant and independent Pves signal in 12/43 patients (28%) of which 8/12 (67%, 5 neurogenic, 3 idiopathic) had detrusor overactivity. The average age of patients with significant and independent signals was 54 5 years and included 6 men and 6 women. CONCLUSIONS: Analysis of LARC during UD testing identified a subset of patients with a significant and independent slow wave frequency in Pves. Further refinements of this technique may help identify subsets of individuals with LARC-mediated OAB/detrusor overactivity.

MP94-10 THE VISCOELASTIC, REVERSIBLY PLASTIC, BEHAVIOR OF DETRUSOR SMOOTH MUSCLE EXPLAINS BLADDER HIGH COMPLIANCE

INTRODUCTION AND OBJECTIVES: : Biological soft tissues are viscoelastic materials because they display time-independent pseudo-elasticity and time-dependent viscosity. Upon an imposed ramp increase then decrease in strain, the resultant increase and decrease in stress, termed loading and unloading respectively, produce nonlinear stress-strain curves, and a reversible reduction in the stress-strain work area that identifies the viscous component. However, there is evidence that bladder tissue may also display plastic behavior, defined as an increase in strain that is unrecoverable unless work is done by the material. In the present study, an electronic lever was used to induce controlled changes in stress and strain to determine whether the material properties of rabbit detrusor smooth muscle (rDSM) represent a viscoelastic or viscoelastic-plastic material. METHODS: Strips of DSM free from underlying mucosa were removed from rabbit bladders. Each tissue was placed in an organ bath connected to an electronic lever and length-adjuster and subjected to a length-tension protocol to identify the length (Lref) that produced the strongest active force induced by KCl. Each ring was subsequently set to 80% Lref and subjected to sequential ramp loading and unloading cycles, stress-strain and stiffness-stress analyses, and a step-loading, load-clamp, step-unloading (creep) protocol. RESULTS: Ramp loading-unloading cycles revealed that rDSM displayed reversible viscoelasticity. The viscous component was responsible for establishing a high stiffness at low stresses that increased only modestly with increasing stress compared to the large increase produced when the viscosity was absent and only pseudoelasticity governed tissue behavior. The creep protocol revealed that rDSM underwent extensive softening correlating with plastic deformation and creep that was reversible upon activation of muscle contraction. Softening reversal was prevented by inhibitors of actomyosin crossbridge cycling. CONCLUSIONS: Together, the data support a model of DSM as exhibiting not only viscoelasticity, but also plasticity, the degree of which is controlled by the degree of motor protein activation. This model explains the mechanism of instrinsic bladder compliance as “slipping” crossbridges, predicts that wall tension is dependent not only on vesicle pressure and radius but also on actomyosin crossbridge activity, and identifies a novel molecular target for compliance regulation both physiologically and therapeutically.