Flow Starting Point and Voiding Mechanisms Measured by Simultaneous Registrations of Intravesical, Intra-abdominal, and Intraurethral Pressures in Awake Rats / 대한배뇨장애요실금학회지

PURPOSE: The aim of this study was to apply a new surgical procedure that allows for the successful monitoring of intraurethral pressure (IUP) changes in the cystometry of awake Sprague-Dawley rats. METHODS: Twenty-six female Sprague-Dawley rats were grouped according to the catheterization method (bladder only; bladder and urethra; or bladder, urethra, and abdomen). Using an arbitrarily determined initial point of the first phase among four rat micturition phases on the simultaneous curves as a reference point, we compared the time differences to the points on an intravesical pressure (IVP) and those on IUP or a detrusor pressure (DP) curve from intra-abdominal pressure (IAP). RESULTS: In awake rat, the start of urethral flow on IUP curve corresponded to the initial point of the second phase, which is same to the results on the anesthetized rat. However, certain results, such as micturition pressure (MP) and intraluminal pressure high-frequency oscillations (IPHFOs), differed between awake and anesthetized rats. Most MP values were checked after the end of urethral flow on the IUP curve, which is due to the peculiar methodology such as transvesical catheterization. Urethral flow was not completely interrupted during the IPHFOs, which suggests the presence of urethral wall tension against the flow during voiding. After removal of the superimposed effects of IAP from IVP, the DP curve clearly showed a peculiar shape, highlighting the possibility of using IAP in place of IUP to detect the flow starting point on the IVP curve. CONCLUSIONS: Awake rat cystometry results have been interpreted based on those in anesthetized rats. However, our awake cystometry data were substantially different in terms of voiding time compared to those of anesthetized rats. This discovery warrants careful interpretation of the voiding parameters in awake rat cystometry.

Transvaginal Cystocele Repair by Purse-String Technique Reinforced with Three Simple Sutures: Surgical Technique and Results / 대한배뇨장애요실금학회지

PURPOSE: Different techniques for cystocele repair including the conventional anterior colporrhaphy and mesh technique are known. Our goal was to evaluate the anatomical success and safety of our method of transvaginal anterior vaginal wall repair by the purse-string technique reinforced with three simple additional sutures in the repair of cystocele over a 4-year follow-up period. METHODS: This was a retrospective review of 69 consecutive patients (grades 2 to 4) who underwent the above operations between 2001 and 2011, including their success rates as assessed by use of the Baden-Walker halfway classification system. RESULTS: Of the patients, 62 patients (98%) were completely cured of cystocele and 1 patient showed grade 2 cystocele recurrence that required no further treatment. Two patients with grade 4 cystocele were completely cured. There was no vaginal erosion related to the cystocele repair. CONCLUSIONS: Transvaginal anterior colporrhaphy by a purse-string technique reinforced with simple additive sutures appears to be a simple, safe, and easily performed approach in cystocele repair. There is no need for other material for reinforcement, even in high-grade cystocele, which is an advantage of our technique.

Time-Related Changes in Detrusor Overactivity in Awake Rats with Spinal Cord Injury Observed by Simultaneous Registrations of Intravesical and Intraabdominal Pressures / 대한배뇨장애요실금학회지

PURPOSE: To compare the physical characteristics of detrusor overactivity (DO) induced by intravesical infusion of saline in awake, sham rats and rats with chronic spinal cord injury (SCI), by simultaneous registrations of intravesical and intraabdominal pressures. METHODS: Male Sprague-Dawley rats, normal or with a spinal vascular clip at the level of Th9, were investigated cystometrically 1 and 4 weeks after SCI. Intra-vesical pressure (IVP) and intra-abdominal pressure (IAP) were recorded simultaneously to evaluate true DO. During the filling phase, the event of IVP rises, defined as increments that exceeded 2 cmH2O from baseline, were determined as DO according to the absence of simultaneous changes in IAP. RESULTS: All SCI rats exhibited DO during the filling phase, which was not shown in sham rats. The frequency and pressure of DO had a tendency to decrease with time. The DO frequency of SCI rats after 4 weeks (0.9+/-0.2 min(-1)) was decreased compared with that after 1 week (2.1+/-0.4 min(-1); P0.05). CONCLUSIONS: Cystometric studies in awake male SCI rats showed some significant changes in bladder function after SCI. All SCI rats exhibited DO during the filling phase, and showed different physical characteristics of DO over the course of time. The neurological basis of these time-related changes remains poorly understood, but may provide important prognostic information about long-term urological management in SCI patients.

Erratum: Urodynamic Findings in an Awake Chemical Cystitis Rat Model Observed by Simultaneous Registrations of Intravesical and Intraabdominal Pressures / 대한배뇨장애요실금학회지

No abstract available.

Early Sequential Changes in Bladder Function after Partial Bladder Outlet Obstruction in Awake Sprague-Dawley Rats: Focus on the Decompensated Bladder

PURPOSE: We investigated bladder function, with special focus on initial functional changes, by objective report of decompensated bladder according to the percentage of residual urine volume to bladder capacity in awake, obstructed rats. MATERIALS AND METHODS: Thirty rats were randomly subjected to sham operations (n=10) or partial bladder outlet obstruction (BOO, n=20). Cystometric investigations were performed without anesthesia 1 or 2 weeks after BOO surgery. To reduce the influence of confounding factors in awake cystometry, we used simultaneous recordings of intravesical and intraabdominal pressures. Decompensated bladder was defined as the bladder with more than 20% of residual volume compared with bladder capacity. RESULTS: Compared with that in sham animals, basal pressure was elevated in both BOO groups. Threshold pressure was higher in the 2 week BOO (p<0.01) group. Compliance was decreased in the 1 week BOO group (p<0.01) and increased in the 2 week BOO group (p<0.001). Bladder capacity was not increased in the 1 week BOO group, but was increased in the 2 week BOO group (p<0.01). Decompensation was found in 62.5% of the 1 week BOO group and in 33.3% of the 2 week BOO group. CONCLUSIONS: From the earlier phase, the bladders exhibited serial changes in pressure and volume parameters, and decompensated bladders defined by the percentage of residual volume to bladder capacity could be seen. During the later phase, there was an increasing tendency of compensated bladders, accompanied by the bladders being enlarged and more compliant.

Dissimilar Effects of Tolterodine on Detrusor Overactivity in Awake Rats with Chemical Cystitis and Partial Bladder Outlet Obstruction / 대한배뇨장애요실금학회지

PURPOSE: We investigated bladder function, with a special focus on nonvoiding contractions (NVCs), in awake rats with chronic chemical cystitis and bladder outlet obstruction (BOO) by use of simultaneous registrations of intravesical and intraabdominal pressures. In addition, we tested the effects of tolterodine on the NVCs in these models. METHODS: A total of 20 female Sprague-Dawley rats were used in this study. In eight rats, chemical cystitis was induced by intravesical instillation of HCl. Twelve rats were subjected to sham instillations or partial BOO. Four weeks after intravesical instillation or 2 weeks after partial BOO, cystometrograms were obtained by use of simultaneous recording of intravesical and intraabdominal pressure in all unanesthetized, unrestrained rats in metabolic cages. RESULTS: A total of 17 rats survived. In the rats with acute injury by HCl, 50% showed detrusor overactivity (DO), which was not seen in the sham group. The cystitis group had lower DO pressure without a difference in DO frequency compared with the BOO group. After the administration of tolterodine, the cystitis group showed no difference in DO frequency or pressure, whereas the BOO group showed decreased values for both parameters. CONCLUSIONS: Our study showed that toleterodine produced no effect on DO during the filling phase in rats with chronic chemical cystitisbut decreased the frequency and pressure of DO in rats with BOO. Clinically, studies are needed to improve the treatment effect of anticholinergic drugs ininterstitial cystitis patients with overactive bladder.

Development and Changes with Age of Detrusor Overactivity in Spontaneous Hypertensive Rats as Observed by Simultaneous Registrations of Intravesical and Intraabdominal Pressures / 대한배뇨장애요실금학회지

PURPOSE: Overactive bladder is especially common in the elderly, although it is not regarded as a normal part of aging. Thus, we investigated how aging alters the cystometric and detrusor overactivity (DO) parameters and the density of nerve growth factor (NGF) in awake spontaneous hypertensive rats (SHRs) of different ages. METHODS: Three age groups of 12- (n=5), 17- (n=6), and 21- (n=6) week-old SHRs (Oriental Bio Inc.) were used. A catheter was implanted into the bladder to record the intravesical pressure (IVP), and a balloon-fitted catheter was positioned in the abdominal cavity to record the intraabdominal pressure (IAP). Of the IVP elevations above 2 cm H2O, DO was defined as a rise in IVP without a simultaneous change in IAP and was counted during the filling phase. We measured the expression of NGF in the bladders by enzyme-linked immunosorbent assay. RESULTS: Both the body and bladder weights significantly increased with age, but the normalized ratio between those was not changed. As for DO, none of the12-week-old rats showed DO, whereas the other groups did. DO increased significantly with age (P=0.0045 by Mantel-Haenszel trend test), although no significant differences were found in DO frequency or pressure between the 17- and 21-week-old age groups. NGF did not show any significant differences among the three groups. CONCLUSIONS: Our results showed that SHRs begin to shows DO after a certain age, such as 12 weeks of age, and that the occurrence of DO has a close relationship with aging. However, NGF, which is known to be increased in the bladder wall of patients with overactive bladder, did not show any relationship with aging in this study.

Urodynamic Effects of Propiverine on Detrusor Overactivity and Abdominal Straining during Voiding in Awake Rats with Intravesical Prostaglandin E2 Instillation

PURPOSE: We investigated the effect of propiverine on cystometric parameters based on intraabdominal pressure (IAP) in awake rats in an overactive bladder (OAB) model induced by intravesical instillation of prostaglandin E2 (PGE2). MATERIALS AND METHODS: Twenty-two female Sprague-Dawley rats were used. Polyethylene catheters were implanted into the bladder to record the intravesical pressure (IVP) and into the femoral artery to administer medication. A balloon-fitted catheter was positioned in the abdominal cavity to record the IAP. Awake cystometries were performed before and after intraarterial administration of propiverine 1 mg/kg (n=6), intravesical administration of 50microM PGE2 only (n=6), or intravesical PGE2 plus 1 mg/kg (n=4) or 3 mg/kg (n=6) of intraarterial propiverine. Cystometric pressure and volume parameters and variables related to detrusor overactivity (DO) were investigated. RESULTS: Rats administered intravesical PGE2 showed increased pressure parameters and decreased volume parameters comparable to the DO model, which was effectively prevented by propiverine (1 or 3 mg/kg). Typical DO shown during the filling phase was decreased by intraarterial propiverine (3 mg/kg) injection. After propiverine (3 mg/kg) injection, IAP was increased at the time of micturition pressure with or without threshold pressure (p<0.05, p<0.01) depending on the dose administered. CONCLUSIONS: Propiverine improved pressure- and volume-related parameters in an OAB model. Furthermore, it also decreased the frequency of DO. However, higher concentrations of propiverine induced straining voiding.

Intravesical PGE2 Administration in Conscious Rats as an Experimental Model of Detrusor Overactivity Observed by Simultaneous Registrations of Intravesical and Intraabdominal Pressures / 대한배뇨장애요실금학회지

PURPOSE: The urodynamic effects of intravesical PGE2 instillation on bladder function and detrusor overactivity (DO) during the filling phase were investigated in rats by measuring intraabdominal and intravesical pressures simultaneously. MATERIALS AND METHODS: Continuous cystometry was performed inconscious, female and male Sprague- Dawley rats. We investigated pressure-, volume-, and DO-related parameters. RESULTS: Intravesical instillation of PGE2 increased all pressure-related parameters and decreased volume-related ones, compared to the control cystometric ones. However, among the total number of intravesical pressure rises (IVPRs) above 2 cmH2O during the filling phase, only 33% in female rats and 38% in male rats after PGE2 instillation were identified as true DO during the filling phase. CONCLUSIONS: Our findings suggest that the rat model with intravesical PGE2 is inappropriate for observing the effects of some drugs or mechanisms on DO, because only approximately 30% of IVPRs were confirmed as true DO. However, this model of intravesical PGE2 instillation has some advantages for the observation of changes in pressure and volume parameters rather than in DO-related ones.

Urodynamic Findings in an Awake Chemical Cystitis Rat Model Observed by Simultaneous Registrations of Intravesical and Intraabdominal Pressures / 대한배뇨장애요실금학회지

PURPOSE: The aim of this study was to investigate the effect of urinary bladder inflammation on bladder function in a rat chemical cystitis model. We also histologically confirmed the effects of inflammation in the detrusor on chronically inflamed bladder in rats. MATERIALS AND METHODS: A total of 13 female Sprague-Dawley rats were used in this study. In seven rats, intravesical instillation of HCl induced chemical cystitis, and the other rats with intravesical instillation of saline were used as the sham. After 2 weeks, cystometrograms were obtained with additional intraabdominal pressure measurements in all unanesthetized, unrestrained rats in metabolic cages. The rats were killed just after cystometry. The bladders were removed and examined histologically for mast cells and inflammatory changes. RESULTS: The rats with acute injury by HCl showed no differences in pressure parameters, including basal pressure, threshold pressure, and maximum bladder pressure, compared with the sham rats. They showed significantly increased bladder capacity, micturition volume, residual volume, and micturition interval compared with the sham group. They also showed an increased frequency of detrusor overactivity compared with the sham group. The percent of detrusor overactivity was 56.3% among the total intravesical pressure rises above 2 cmH2O. The histological findings of the rats with acute injury by HCl were consistent with chemical cystitis. CONCLUSIONS: Overlapping patterns of lower urinary tract symptoms and pelvic pain are common disease characteristics among interstitial cystitis patients. The situation in an animal model of interstitial cystitis is similar, as observed in this study by the histologic and awake cystometric examinations. However, the interstitial cystitis model showed detrusor overactivity during the filling phase without a decrease in bladder capacity and micturition intervals, which differs from the characteristics of overactive bladder patients.

The Effect of Suprapubic Magnetic Stimulation in Patients with Neurogenic Detrusor Overactivity

PURPOSE: To evaluate the effect of suprapubic magnetic stimulation (SMS) with the use of an arm-type magnetic stimulator for the treatment of patients with neurogenic detrusor overactivity. MATERIALS AND METHODS: Eleven patients with neurogenic detrusor overactivity were enrolled in this study. All patients underwent more than 16 SMS sessions, two times per week, with the use of an arm-type magnetic stimulator. Objective success was defined as a significant reduction (> or =50%) in the total number of leakage episodes per 24 hours, whereas subjective success was defined as the request to continue treatment. RESULTS: Five (71.4%) of 7 patients who had urinary incontinence before treatment reported objective success, and 3 patients showed no incontinence. A total of 6 (75.0%) of 8 patients showed increased average voiding volume. One patient showed an adverse effect of back pain after SMS and dropped out. Seven patients (70.0%) of 10 patients wanted to continue this treatment. They showed significant improvements in frequency/volume chart data, quality of life scores, and urodynamic data. CONCLUSIONS: SMS can be a safe, non-invasive and effective option for the treatment of neurogenic detrusor overactivity.

The Effect of tolterodine Via Oral and Intravenous Administrations on Voiding in Awake Spontaneously Hypertensive Rats as an Overactive Bladder Model

PURPOSE: We investigated the effect of oral or intravenous tolterodine on cystometric parameters in awake spontaneously hypertensive rats (SHRs) as a model of overactive bladder (OAB). The aim of our study was to observe the experimental conditions required to reproduce the clinical pharmacological effects of tolterodine, as seen in humans, to decrease bladder pressure or increase bladder capacity. MATERIALS AND METHODS: We studied the effects of the most widely used antimuscarinic drug, tolterodine, on cystometric parameters via two different administrations (oral and intravenous) in awake SHRs. RESULTS: Oral administration of tolterodine 10 mg/kg(-1) body weight in awake rats did not change any cystometric parameters significantly. Intravenous administration of tolterodine 0.3 mg/kg(-1) body weight significantly decreased basal pressure (BP) and micturition pressure (MP), but showed no effect on micturition interval (MI) or bladder capacity (BC). CONCLUSION: Despite a high dose of tolterodine via an oral or an intravenous route, a decrease in BP or MP was the only effect on cystometrographic parameters in awake rats, whereas MI and BC were not significantly affected. Therefore, it is difficult to reproduce in awake rats as an acute response the cystometric increase in the MI that is observed in humans after chronic administration of antimuscarinic agents.

Application and Limitations of Awake Cystometry in Sprague-Dawley Rats with Partial Bladder Outlet Obstruction as a Model of Overactive Bladder or Obstruction

PURPOSE: Partial bladder outlet obstruction (PBOO) in rats leads to changes in bladder function, such as obstruction and detrusor overactivity (DO). The aim of our study was to observe factors essential for the objective descriptions of PBOO rats as an overactive bladder model as well as an obstruction model under awake cystometry. We also aimed to investigate the urodynamic effects of PBOO objectively in view of DO-related parameters as well as conventional pressure and volume-related parameters. MATERIALS AND METHODS: PBOO was produced in 10 female Sprague-Dawley rats by ligating the proximal urethra over a 0.9 mm metal rod; 10 sham-operated rats were used as controls. Intravesical pressure (IVP) was recorded via an open catheter in the bladder, and intraabdominal pressure (IAP) via an intraabdominal balloon catheter. Continuous cystometry was performed 2 weeks after the PBOO procedure. Conventional and newly developed DO-related urodynamic parameters were investigated. RESULTS: PBOO led to a significant increase in bladder weight. Three rats showed the picture of decompensated bladder and were excluded from the analysis. The obstructed group showed some increased pressure- and volume-related parameters. They showed a DO frequency of 1.5+/-0.3/min, but the sham group did not. CONCLUSIONS: Our results showed that bladder decompensation can happen after PBOO, and we need to describe those exclusions accurately in reports. In conscious PBOO rats, simultaneous registration of IAP and IVP is needed for accurate investigations of DO, because PBOO can lead to DO as well as bladder hypertrophy.

The Value and Limitations of Intravesical Prostaglandin E2 (PGE2)-induced Bladder Hyperactivity as an Overactive Bladder Model in Normal, Conscious Sprague-Dawley Rats / 대한비뇨기과학회지

PURPOSE: Establishing an appropriate animal model is essential for investigating the yet unknown mechanisms of overactive bladder(OAB). Prostanoids are an already well known intrinsic cause of overactive bladder in both animal and human. Awake animal models with prostanoids are already being used as an OAB model, but there is no standardization of methods, and especially for the concentration of the administrated prostanoids. So in this study, we tried to objectively establish the standardized concentration of prostanoids and its effect on urination through urodynamic studies with using non-anesthetized Dawley rats. MATERIALS AND METHODS: We divided 18 female rats(215-280g) into 3 groups of six rats each and we injected 30micrometer, 50micrometer or 100micrometer of PGE2, respectively. A catheter was placed inside the bladder through an incision in the abdominal wall. After three days, cystometry was performed with the arts in an awake state. During cystometry, we administrated saline into the bladder to identify the usual voiding status of the rat. In comparison, the saline with PGE2 at 3 different concentrations(30, 50, 100micrometer) was administrated into the bladder(10ml/h). RESULTS: Each group of the 30, 50, 100micrometer PGE2 administered rats showed an increased level of the basal pressure, the threshold pressure and the maximal pressure compared to the state before administration of PGE2. Also, the bladder capacity, voided volume and micturition interval decreased by a statistically acceptable amount, like was seen in the OAB model. There was a trend that showed a greater increase in the pressure parameters and a greater decrease in the volume parameters in the 50micrometer PGE2 group compared to the 30micrometer PGE2 group, but there were no differences between the 50micrometer and 100micrometer groups. CONCLUSIONS: In the normal awake rats, PGE2 induced overactive bladder to a statistically significant amount for all concentrations(30, 50, 100micrometer). Among these groups, the concentration of 50micrometer provoked OAB most effectively, and the higher concentration of PGE2(100micrometer) did not provoke a more efficient OAB, which might have been due to the characteristics of the intrinsic material in the bladders. Thus, we recommend PGE2 50micrometer for efficient induction of OAB.

The Different Mechanisms of Awake Micturitions between Male and Female Rats Using an Overactive Model with Intravesical PGE2 Instillation / 대한비뇨기과학회지

PURPOSE: We wanted to obtain informations on the different mechanisms of awake micturitions between male and female rats by using an overactive model with intravesical PGE2 instillation. MATERIALS AND METHODS: Sprague Dawley rats(6 male, 6 female) were used. A catheter was implanted into the bladder to record the intravesical pressure. Three days later, the awake cystometry was performed, and PGE2 was given intravesically to induce detrusor overactivity(DO). With using the conventional pressure and volume parameters, a new parameter of flow pressure was investigated. RESULTS: When recorded as the flow pressure, the male rats exhibited higher urethral resistance than did the female rats in the normal state. The male rats showed higher urethral resistances after DO was induced, than those before the DO. However, the female rats did not show increased urethral resistance after DO was induced. CONCLUSIONS: An increase in urethral resistance through the outlet region was induced in male rats after intravesical PGE2 instillation, but this didn't occur in female rats. This result indicates that overactive bladder has different mechanisms and responses in different genders.