Pyelonephritis in persons after age 50 as a clinical marker of urogenital cancer.

OBJECTIVES: Urinary tract infections have been linked with urinary tract cancer, but the association remains controversial. We examined whether pyelonephritis is a clinical marker of urogenital cancer. METHODS: We used Danish medical databases to create a population-based cohort of patients with an incident hospital-based pyelonephritis diagnosis during 1994-2013. Follow-up for cancer began at pyelonephritis diagnosis and ended on 30 November 2013. We restricted the cohort to patients older than 50 years, as urogenital cancer risk in the younger population is low. We calculated the absolute risk of urogenital cancer and the standardized incidence ratio (SIR) comparing risk observed in pyelonephritis patients to risk expected in the general population of Denmark. RESULTS: Among 15 070 patients with pyelonephritis, we observed 197 urinary tract cancers and 374 genital organ cancers over a 20-year follow-up period. The absolute risk of urogenital cancer was 1.5% 6 months after a pyelonephritis diagnosis, and the cumulative risk was 3.0% at 5 years. During the first 6 months following a pyelonephritis diagnosis, the SIR of urogenital cancer was 8.56 (95% CI 7.49-9.75). Between 6 and 12 months following this diagnosis, the SIR was 1.75 (95% CI 1.26-2.35), and beyond 1 year the SIR was approximately unity for most cancers. Notably, the SIR for bladder cancer among women remained elevated beyond 1 year of follow-up. CONCLUSIONS: Patients presenting with a hospital-based diagnosis of pyelonephritis had a higher 6-month risk of urogenital cancer than expected. However, causation cannot be inferred because of the study design.

Aquaporin expression in the fetal porcine urinary tract changes during gestation.

The expression of aquaporins (AQPs) in the fetal porcine urinary tract and its relation to gestational age has not been established. Tissue samples from the renal pelvis, ureter, bladder and urethra were obtained from porcine fetuses. Samples were examined by RT-PCR (AQPs 1-11), QPCR (AQPs positive on RT-PCR), and immunohistochemistry. Bladder samples were additionally examined by Western blotting. RNA was extracted from 76 tissue samples obtained from 19 fetuses. Gestational age was 60 (n=11) or 100 days (n=8). PCR showed that AQP1, 3, 9 and 11 mRNA was expressed in all locations. The expression of AQP3 increased significantly at all four locations with gestational age, whereas AQP11 significantly decreased. AQP1 expression increased in the ureter, bladder and urethra. AQP9 mRNA expression increased in the urethra and bladder, but decreased in the ureter. AQP5 was expressed only in the urethra. Immunohistochemistry showed AQP1 staining in sub-urothelial vessels at all locations. Western blotting analysis confirmed increased AQP1 protein levels in bladder samples during gestation. Expression levels of AQP1, 3, 5, 9 and 11 in the urinary tract change during gestation, and further studies are needed to provide insights into normal and pathophysiological water handling mechanisms in the fetus.

What is a representative voiding pattern in children with lower urinary tract symptoms? Lack of consistent findings in ambulatory and conventional urodynamic tests.

BACKGROUND: Conventional urodynamics (CU) is a highly standardized evaluation of lower urinary tract function. However, in pediatric patients there is concern that the reliability of measurements could be influenced by development effects and measurement variability, as well as by the unfamiliar clinical environment. Ambulatory urodynamics (AU) provides an alternative to this - it uses natural filling, is measured over a prolonged period, and is conducted in a child-friendly environment. OBJECTIVE: The aim of this study was to conduct a comparative analysis of AU and CU to evaluate the consistency in voiding patterns obtained with these two methods of urodynamic testing. STUDY DESIGN: Urodynamic parameters obtained by AU and CU methods in 50 pediatric patients aged >5 years were retrospectively analyzed. Voiding patterns were categorized into six types: coordinated contraction, detrusor after-contraction, fluctuated contraction, pre-void contraction, relief voiding, and weak or absent contraction. Voiding patterns were used to determine the repeatability within urodynamic tests and to identify consistency between AU and CU tests. Five urodynamic parameters were quantified and compared between AU and CU: voided volume, flow rate, maximum detrusor pressure, and detrusor pressure at peak flow rate. For inter-observer variation analysis, 100 voiding curves were randomly selected and categorized by two independent observers; inter-observer agreement was evaluated using the kappa statistic. RESULTS: A single pattern of voiding was identified in five patients using AU and 37 using CU. Consistency of a single pattern between AU and CU was identified in three patients, and consistency between a predominant pattern with AU, defined by one type of voiding occurring >50% of one's voids, and a single pattern with CU was identified in 10 patients (summary table). Flow rates were similar between methods; however, higher maximum detrusor pressure and detrusor pressure at peak flow and lower voided volume were recorded with AU. DISCUSSION: AU resulted in more diverse voiding patterns. Along with the differences in measured urodynamic parameters challenges the application of findings from one method to form a clinical diagnosis. Furthermore, CU may not be as sensitive as AU to the variability in lower urinary tract pathophysiology. CONCLUSIONS: More diverse voiding patterns were identified in AU compared with CU, with a lack of consistency in identified voiding pattern in both methods. Therefore, the urodynamic findings in children may have to be analyzed in more detail, taking the variations into account.

The effect of puberty on diurnal sodium regulation.

The aim of this study was to investigate the impact of sex and puberty stage on circadian changes in sodium excretion, sodium-regulating hormones, and hemodynamics. Thirty-nine healthy volunteers (9 prepuberty boys, 10 prepuberty girls, 10 puberty boys, and 10 puberty girls) were included. They all underwent a 24-h circadian in-patient study under standardized conditions regarding activity, diet, and fluid intake. Blood samples were drawn every 4 h, and the urine was collected in fractions. Blood pressure and heart rate were noninvasively monitored. Atrial natriuretic peptide (ANP), angiotensin II, aldosterone, and renin were measured in blood. Children in puberty had lower plasma levels of renin (P<0.05) and angiotensin II (P<0.05) and a 26% reduction in filtered sodium without changes in sodium excretion compared with prepuberty children. A circadian rhythm in sodium excretion, the renin-angiotensin system, ANP, and blood pressure was found with a midnight ANP peak (P<0.001), a nighttime decrease in hemodynamic parameters (P<0.001), an increase in plasma renin (P<0.001) and angiotensin II (P<0.001), and a decrease in sodium excretion (P<0.001) mainly on the basis of increased sodium reabsorption (P<0.001). The timing of the changes did not depend on sex or puberty group. There is a circadian rhythm of sodium excretion and sodium regulation in 7- to 15-yr-old children. This rhythm is similar in boys and girls. As an important new finding, puberty changes the plasma levels of renin and angiotensin II without changing the amount of sodium excreted or the day to night sodium excretion ratio.

Urinary concentration does not exclusively rely on plasma vasopressin. A study between genders. Gender and diurnal urine regulation.

AIM: We investigated the influence of gender on the diurnal regulation of urine production with special focus on vasopressin, oxytocin and prostaglandin E2. METHODS: Fifteen young women in mid-follicular phase and 22 young men (20-33 years) were included. All participants underwent a 24-h circadian inpatient study under standardized conditions for measurements of plasma vasopressin, oxytocin, sodium and osmolality. Urine was fractionally collected for measurements of electrolytes, aquaporin-2 and prostaglandin E2. RESULTS: Plasma vasopressin expressed a diurnal rhythm with a night-time increase in both genders (P < 0.001). The ratio between mean daytime and mean night-time was 1.57 [95% CI: 1.33-1.84] P < 0.001 in men and 1.35 [95% CI: 1.11-1.64] P = 0.002 in women. P-vasopressin was higher in males during the night (P < 0.05). There was no difference in diuresis (P = 0.43), urine osmolality (P = 0.12) or aquaporin-2 excretion (P = 0.80) between genders. We found a trend towards a higher reabsorption of free water in males (P = 0.07). The excretion of prostaglandin E2 was higher in males (P < 0.001). There was no diurnal rhythm in p-oxytocin (P = 0.37) and no correlation to diuresis, urine osmolality or aquaporin-2 excretions. CONCLUSION: Similar urinary flows and osmolalities are associated with levels of plasma vasopressin and renal PGE2, which are higher in males than in females. Oxytocin does not seem to play a role in the diurnal urine formation, whereas prostaglandin E2 could represent a mediator of the gender difference, not only as a mediator of the vasopressin response, but also as an independent factor. These findings need further elucidation.

Puberty alters renal water handling.

We investigated the influence of sex and puberty stage on circadian urine production and levels of antidiuretic hormone [arginine vasopressin (AVP)] in healthy children. Thirty-nine volunteers (9 prepuberty boys, 10 prepuberty girls, 10 midpuberty boys, and 10 midpuberty girls) were included. All participants underwent a 24-h circadian inpatient study under standardized conditions regarding Na(+) and fluid intake. Blood samples were drawn every 4 h for measurements of plasma AVP, serum 17-ß-estradiol, and testosterone, and urine was fractionally collected for measurements of electrolytes, aquaporin (AQP)2, and PGE2. We found a marked nighttime decrease in diuresis (from 1.69 ± 0.08 to 0.86 ± 0.06 ml·kg(-1)·h(-1), P < 0.001) caused by a significant nighttime increase in solute-free water reabsorption (TcH2O; day-to-night ratio: 0.64 ± 0.07, P < 0.001) concurrent with a significant decrease in osmotic excretion (day-to-night ratio: 1.23 ± 0.06, P < 0.001). Plasma AVP expressed a circadian rhythm (P < 0.01) with a nighttime increase and peak levels at midnight (0.49 ± 0.05 pg/ml). The circadian plasma AVP rhythm was not influenced by sex (P = 0.56) or puberty stage (P = 0.73). There was significantly higher nighttime TcH2O in prepuberty children. This concurred with increased nighttime urinary AQP2 excretion in prepuberty children. Urinary PGE2 exhibited a circadian rhythm independent of sex or puberty stage. Levels of serum 17ß-estradiol and testosterone were as expected for sex and puberty stage, and no effect on the AVP-AQP2-TcH2O axis was observed. This study found a circadian rhythm of plasma AVP independent of sex and puberty stage, although nighttime TcH2O was higher and AQP2 excretion was more pronounced in prepuberty children, suggesting higher prepuberty renal AVP sensitivity.

Sleep deprivation induces excess diuresis and natriuresis in healthy children.

Urine production is reduced at night, allowing undisturbed sleep. This study was undertaken to show the effect of sleep deprivation (SD) on urine production in healthy children. Special focus was on gender and children at an age where enuresis is still prominent. Twenty healthy children (10 girls) underwent two 24-h studies, randomly assigned to either sleep or SD on the first study night. Diet and fluid intake were standardized. Blood samples were drawn every 4 h during daytime and every 2 h at night. Urine was fractionally collected. Blood pressure and heart rate were noninvasively monitored. Blood was analyzed for plasma antidiuretic hormone (AVP), atrial natriuretic peptide (ANP), angiotensin II, aldosterone, and renin. Urine was analyzed for aquaporin-2 and PGE(2). Successful SD was achieved in all participants with a minimum of 4 h 50 min, and full-night SD was obtained in 50% of the participants. During SD, both boys and girls produced markedly larger amounts of urine than during normal sleep (477 ± 145 vs. 291 ± 86 ml, P < 0.01). SD increased urinary excretion of sodium (0.17 ± 0.05 vs. 0.10 ± 0.03 mmol·kg(-1)·h(-1)) whereas solute-free water reabsorption remained unchanged. SD induced a significant fall in nighttime plasma AVP (P < 0.01), renin (P < 0.05), angiotensin II (P < 0.001), and aldosterone (P < 0.05) whereas plasma ANP levels remained uninfluenced (P = 0.807). Nighttime blood pressure and heart rate were significantly higher during SD (mean arterial pressure: 78.5 ± 8.0 vs. 74.7 ± 8.7 mmHg, P < 0.001). SD leads to natriuresis and excess diuresis in healthy children. The underlying mechanism could be a reduced nighttime dip in blood pressure and a decrease in renin-angiotensin-aldosterone system levels during sleep deprivation.

Age related nocturnal urine volume and maximum voided volume in healthy children: reappraisal of International Children's Continence Society definitions.

PURPOSE: We determined normal, age related reference data regarding maximum voided volume and nocturnal urine production using the same methodology as in clinical practice. MATERIALS AND METHODS: A total of 62 girls and 86 boys without enuresis (mean +/- SD age 9.64 +/- 2.63 years, range 3 to 15) completed 4 days (2 weekends) of frequency-volume charts and 14 days of home recording of nocturnal urine production. From these recordings maximum voided volume with and without first morning void was derived for each subject. Also, average nocturnal urine volume with and without nocturia was calculated. Percentiles were produced by dividing the population into 1-year age groups. RESULTS: Based on 2,836 daytime voids and 1,977 overnight recordings, maximum voided volume and nocturnal urine volume showed a significant linear relationship with age but not with gender. Maximum voided volume with first morning void was significantly higher than without (403 +/- 137 ml vs 281 +/- 112 ml, p <0.0001) and the 50th percentile line of maximum voided volume with first morning void was 80 to 100 ml higher than Koff's formula (30 x [age + 1] ml). Conversely the 50th percentile of maximum voided volume without first morning void was almost identical to Koff's formula. Regarding nocturnal measurements, nocturia was noted on 128 nights (6.5%) and nocturnal urine volume on nights with nocturia was significantly higher than on nights without nocturia (365 +/- 160 ml vs 248 +/- 75 ml, respectively, p <0.0001). The 97.5th nocturnal urine volume percentile line of healthy children deviated markedly from the current International Children's Continence Society definition of nocturnal polyuria, especially at low and high ages. CONCLUSIONS: We demonstrate clearly that the universally used formula 30 x (age + 1) ml is indeed valid for a population of healthy Danish children but only if the first morning void is disregarded. Furthermore, we question the validity of the current International Children's Continence Society formula for nocturnal polyuria (nocturnal urine volume greater than 130% of maximum voided volume for age), and instead we propose the formula, nocturnal urine volume greater than 20 x (age + 9) ml.

Evaluation of complete and partially obstructed kidneys using Gd-DTPA enhanced dynamic MRI in adolescent swine.

PURPOSE: Aim of this study was to evaluate the dynamic changes in renal relative signal intensity (RSI) following the administration of Gd-DTPA in adolescent pigs with complete and partial unilateral ureteric obstruction. METHODS: Pigs were divided into 3 groups: partial and complete unilateral ureteric obstruction and controls. Complete unilateral ureteric obstruction (CUUO) was created by ligating the left ureter, whereas partial unilateral ureteric obstruction (PUUO) was created in pigs of 2 weeks of age by embedding the left ureter into the psoas muscle. Dynamic MRI was performed before and at 0 - 60 min after an intravenous bolus injection of Gd-DTPA. Mean RSI of the renal cortex, medulla and pelvis was measured and interpreted as an indirect measure of the renal function. In addition, renography was performed, and renal morphology was examined IN VITRO. RESULTS: Three phases of RSI were identified. The dynamic RSI patterns differed markedly between obstructed and control kidneys. In PUUO kidneys, Phase 1 of the mean RSI of the cortex and medulla demonstrated a decreased amplitude and prolonged duration, whereas in Phase 2 the mean RSI of the pelvis was increased. In acute CUUO kidneys, the mean RSI patterns were similar to those of controls, except for a significant increase of the pelvic mean RSI. CONCLUSIONS: Gd-DTPA enhanced dynamic MRI allowed a characterization and differentiation of renal function and morphology of normal and obstructed kidneys, and secondly, provided potentially important information on renal concentrative and filtration availability.

Irrigation with isoproterenol diminishes increases in pelvic pressure without side-effects during ureterorenoscopy: a randomized controlled study in a porcine model.

OBJECTIVE: Recently, we showed that endoluminally administered isoproterenol (ISO) inhibits muscle function of the pyeloureter in swine. This may be of value in managing increases in pelvic pressure during upper urinary tract endoscopy. The purpose of this study was to examine the effect of endoluminally administered ISO on increases in pelvic pressure and cardiovascular function during flexible ureterorenoscopy. MATERIAL AND METHODS: The study was performed in anaesthetized female pigs. In terms of endoscopic procedures, the pigs were randomized as follows: Group 1, irrigation with 0.1 microg/ml ISO added to saline (n=12); and Group 2, irrigation with saline (n=10). A 5-Fr catheter was retrogradely placed in the renal pelvis and an 8-Fr catheter in the bladder for pressure measurements. Flexible ureterorenoscopy was performed with constant irrigation at a perfusion rate of 8 ml/min. Pelvic, bladder and blood pressure and heart rate were registered continuously. RESULTS: Mean baseline pelvic pressure was identical in both groups: 12+/-2.3 mmHg in Group 1 and 14+/-3.6 mmHg in Group 2 (p=0.26). During ureterorenoscopy, mean pelvic pressure increased to 26+/-2.3 mmHg in Group 1 and to 38+/-3.1 mmHg in Group 2. Hence ISO reduced the pressure increase due to ureterorenoscopy by 42% (p<0.001). Pelvic pressure seemed to be independent of bladder pressure, which showed no difference between the two groups (p=0.067). Blood pressure and heart rate showed no significant differences between the two groups: p=0.425 and p=0.166, respectively. CONCLUSIONS: ISO (0.1 microg/ml) added to irrigation fluid significantly reduces the increase in pelvic pressure during ureterorenoscopy in pigs, without concomitant side-effects.

Cyclooxygenase type 2 is increased in obstructed rat and human ureter and contributes to pelvic pressure increase after obstruction.

Prostanoids exert physiological effects on ureteral contractility that may lead to pressure changes and pain during obstruction. In the present study, we examined whether (1) obstruction changes the expression of the two cyclooxygenase (COX) isoforms, COX-1 and COX-2 in human and rat ureters and (2) administration of a selective COX-2 inhibitor influences the pelvic pressure change after experimental ureteral obstruction. Rats were subjected to bilateral ureter obstruction. Ureters were removed and dissected into a proximal dilated and distal non-dilated segment. RNA and protein were extracted and analyzed for cyclooxygenase expression by quantitative polymerase chain reaction and Western blotting. Human ureter samples were obtained from patients undergoing radical nephrectomy. Rat and human ureteral samples were processed for immunohistochemistry. COX-1, but not COX-2 mRNA, was readily detected in the normal rat ureter. COX-2 mRNA and protein expression was increased in the proximal dilated ureter compared to distal non-dilated ureter. This increased COX-2 expression was associated with increased urinary prostaglandin E2 (PGE2) excretion after release of obstruction. Immunohistochemistry showed increased COX-2 labeling in surface epithelium and smooth muscle layers in both rat and human obstructed ureters compared to control ureters. Furthermore, contractile PGE2-EP1 and thromboxane TP receptors were expressed in ureteral smooth muscle. Systemic treatment with the COX-2 selective inhibitor parecoxib (5 mg/kg/day) attenuated the pelvic pressure increase during obstruction. In summary, COX-2 expression is significantly increased in the ureteral wall in response to obstruction in the rat and human ureter and COX-2 activity contributes to increased pelvic pressure after obstruction.

Nocturnal polyuria in monosymptomatic nocturnal enuresis refractory to desmopressin treatment.

The transition from day to night is associated with a pronounced decline in diuresis with reductions in the amount of excreted water, electrolytes, and other end products of our metabolism. Failure to do so leads to a large urine output at night, a condition known as nocturnal polyuria, encountered in a large proportion of children with nocturnal enuresis. The aim of this study was to clarify the mechanisms responsible for the nocturnal polyuria seen in enuretics with inadequate response to desmopressin (dDAVP). Forty-six enuretics (7-14 yr of age) and fifteen age-matched controls were admitted for a 24-h protocol with standardized fluid and sodium intake, comprising urine collections, blood sampling, and blood pressure monitoring. We included patients with severe enuresis (5 +/- 1 wet nights/wk) showing <50% reduction in wet nights on dDAVP. We characterized the patients on the basis of their nocturnal urine production. The children with nocturnal polyuria excreted larger amounts of sodium and urea at night than nonpolyurics and controls. Solute-free water reabsorption as well as urinary arginine vasopressin and aquaporin-2 excretion were normal in polyurics, and no differences were found in atrial natriuretic peptide, angiotensin II, aldosterone, and renin levels. Urinary prostaglandin E2 (PGE2) excretion was significantly higher in polyurics. The nocturnal polyuria in children with dDAVP-resistant nocturnal enuresis seems to be the result of augmented sodium and urea excretion. The high urinary PGE2 levels found in these children point toward a role for increased prostaglandin synthesis in the pathogenesis of enuresis-related polyuria.

Ano-rectal motility responses to pelvic, hypogastric and pudendal nerve stimulation in the Göttingen minipig.

UNLABELLED: We investigated the effect of efferent stimulation of the pelvic (PN), hypogastric (HGN) and pudendal (PuN) nerves on ano-rectal motility in Göttingen minipigs using an impedance planimetry probe. Changes in the rectal cross-sectional area (CSA) at five axial positions and pressures in the rectum and anal canal were investigated simultaneously. Pelvic nerve stimulation elicited a CSA decrease in the proximal part of the rectum and a simultaneous CSA increase in its distal part. Anal pressure also decreased. Hypogastric nerve and PuN stimulation elicited an increase in anal pressure, but no rectal response. Severing the HGN produced a persistent reduction in resting anal pressure, but no change was observed when the PN and the PuN were severed. Stimulation of the distal part of all three nerves produced a persistent response. Administration of phentolamine and pancouronium eliminated the response to stimulation of the HGN and the PuN, respectively. CONCLUSION: Rectal responses to PN stimulation vary more than previously suggested. The HGN has an excitatory effect on the internal anal sphincter, and the PuN on the external anal sphincter. However, the PuN plays no major role in maintaining basal anal pressure.

Anorectal motility responses to selective stimulation of the ventral sacral nerve roots in an experimental model.

BACKGROUND: Control of defaecation and continence may be lost in patients with spinal cord injury. Electrical stimulation of sacral nerve roots to promote defaecation simultaneously activates both the rectum and the external anal sphincter (EAS), and may actually obstruct defaecation. The aim of this study was to investigate whether the EAS could be blocked selectively by selective stimulation of the ventral sacral nerve roots, and whether activation of the rectum without activation of the EAS could be obtained by stimulation of the ventral sacral nerve roots. METHODS: Selective electrical stimulation was performed using anodal blocking, a tripolar cuff electrode and monophasic rectangular current pulses applied to the sacral nerve roots in nine Göttingen minipigs. RESULTS: Simultaneous responses in the rectum and the anal canal were observed in five animals, whereas only anal responses were noted in four. Variations in cross-sectional area and an increase in rectal pressure seemed to facilitate defaecation. Without blocking, the increase in anal canal pressure was 16-45 cmH(2)O. With blocking, this increase was abolished in seven and reduced to 3-6 cmH(2)O in two animals. CONCLUSION: Selective activation of the rectum is possible using an anodal block of somatic motor fibres. This technique holds promise in further development of electro-defaecation.

Design and evaluation of an ultrasound-based bladder volume monitor.

Ultrasonic bladder volume monitors have successfully been used in the diagnosis and treatment of various urological disorders. Ultrasonic bladder monitors have been developed but they have either been too bulky or too simple and inaccurate. A new, wearable ultrasonic bladder volume monitor has been designed for urological patients. The instrument consists of seven phased-array ultrasonic transducers ergonomically arranged in a circular pattern to optimise detection of the bladder walls perpendicular to the abdominal wall. A Bluetooth radio link was used to transmit data to a laptop computer, where the main signal processing was performed. After detection of bladder surface points, a three-dimensional convex hull representing the bladder was generated, and the volume was estimated. Accuracy, precision, drift over time, temperature dependency and dynamic performance were evaluated using ultrasound phantoms. Furthermore, the system was tested on one volunteer using magnetic resonance imaging (MRI) as reference. The apparatus showed no significant drift, systematic error or temperature effects. Percentage error during static volume measurements had a 95% central prediction interval of +/-7.5% and mean absolute percentage error of 2.9%. The dynamic performance analysis showed linearity in the analysed volume interval. The in vivo study showed a high degree of correlation (R2= 0.99) between the volume measured using MRI and that measured with the apparatus.

Twenty-four-hour ambulatory urodynamics in healthy young men.

OBJECTIVE: To describe normal natural fill urodynamics in young men during normal and increased fluid intake. MATERIAL AND METHODS: Thirty healthy males aged 21-32 years volunteered for an ambulatory urodynamic 24 h investigation with a suprapubic catheter. The recorded micturition data were: frequency (f), voided volume (VV), voiding time, maximal flow rate (Qmax) and time to Qmax. The number of sensed and not-sensed bladder contractions, duration and time in relation to voiding were also recorded. During the recording day subjects were randomized to normal (30 ml/kg body weight per day) or larger (60 ml/kg body weight per day) fluid intake. RESULTS: As expected there was a larger urine production and an increased voiding frequency in the fluid-loaded group (p<0.0001). The detrusor pressure (Pdet) Qmax was significantly higher in the fluid-loaded group (73 cmH2O, range 57-94) than in the normal fluid intake group (60 cmH2O, range 45-86) (p=0.003). No other urodynamic data differed significantly between the two groups. When comparing the ambulatory urodynamic data with previously obtained home flowmetry recordings from the same volunteers differences were only found in voiding frequency. The majority of participants had detrusor contractions, felt and unfelt, during the filling phase. Three types of detrusor activity during voiding phase could be described: type 1, with one micturition contraction, type 2, with several small contractions before micturition, and type 3, with large prolonged contractions leading to micturition. CONCLUSIONS: Ambulatory urodynamics in normal young men showed a large interindividual variation. Bladder contractions during filling were frequently recorded, and premicturition contractions were consistently found. The data found in this study were similar to previous home flow recordings in the same group.

Biomechanical properties of the anterior urethra of the male rabbit--a study using impedance planimetry.

OBJECTIVE: To evaluate the anterior urethra of the male rabbit regarding its luminal cross-sectional area (CSA), CSA distensibility, circumferential tension-strain relation, histology and the collagen content of the tissue. material and methods: Nineteen rabbits were examined with impedance planimetry by distending the urethra at the passage from the spongious to the bulbous part and 1 cm proximally in the bulbous part. Four weeks later, eight rabbits underwent a second examination. After the measurements the urethras were processed for either histology or determination of collagen content. The urethras from six additional rabbits served as controls for histology and collagen content. RESULTS: The CSA and the CSA distensibility were smaller at the distal than the proximal distension site. At both sites the CSA distensibility was high at low luminal pressure loads and decreased with increasing pressure. The circumferential tension-strain plot displayed an exponential relation, with a steeper slope distally than proximally. Repeated biomechanical investigation revealed a significantly increased CSA and a decreased slope of the circumferential tension-strain relation at both distension sites. The biomechanical investigation induced abrasion of the epithelium, extravasation of erythrocytes and separation of the collagen fibres, suggesting oedema of the luminal part of the wall. After 4 weeks the epithelium had changed from transitional to stratified, squamous and often keratinized epithelium and the collagen beneath the epithelium formed a dense network instead of wavy lines as seen in the control urethras. The collagen content was larger at the distal than the proximal distension site. No change in collagen content could be demonstrated between the urethras investigated once or twice with impedance planimetry. CONCLUSIONS: The non-linear pressure-CSA, pressure-CSA distensibility and circumferential tension-strain relations found at both distension sites demonstrate that the urethra yields readily at low pressures, thus facilitating flow. At higher pressure loads, the tissue becomes less distensible, a property that protects it against over-distension and damage. Impedance planimetry cannot be used to study before-and-after phenomena as the biomechanical investigation changed both the histology and the biomechanical properties of the rabbit urethra.

Monosymptomatic nocturnal enuresis is associated with abnormal nocturnal bladder emptying.

PURPOSE: We investigate the nature of enuresis episodes in monosymptomatic nocturnal enuresis using a fluid provocation model. MATERIALS AND METHODS: The study included 18 children 7 to 13 years old with monosymptomatic nocturnal enuresis. Based on basal home recordings patients were subgrouped into those with a normal nocturnal urine output and those with nocturnal polyuria (mean nocturnal urine production on wet nights exceeding 130% of functional bladder capacity, normal functional bladder capacity for age provided). Children were admitted to the hospital for 4 consecutive nights. After an adaptation night all children received orally 25 ml/kg water, 30 minutes before bedtime on the remaining 3 nights. A cordless alarm device enabled registration of enuretic episodes from another room and diapers allowed the measurement of enuresis volumes. Post-void residual volumes were measured by ultrasound. Pelvic floor electromyography was continuously recorded throughout the night, and its association to bladder emptying was investigated. RESULTS: A total of 95 enuresis and 14 nocturia episodes were recorded. Significantly more enuresis episodes were registered on nights with oral fluid load, whereas no increase in number of nocturia episodes was seen. Of the enuresis episodes 46 were associated with incomplete bladder emptying (post-void residual volume greater than 10% of total bladder volume at time of enuresis). No difference between patient groups regarding post-void residual volume was seen. Abnormal bursts of electromyography activity were associated with incomplete micturitions. CONCLUSIONS: Enuresis nocturna episodes in polyuric and nonpolyuric patients are frequently incomplete micturitions. The present findings question the definition of nocturnal enuresis episode as normal complete voiding.