Tamsulosin 0.4 mg once daily: tolerability in older and younger patients with lower urinary tract symptoms suggestive of benign prostatic obstruction (symptomatic BPH). The European Tamsulosin Study Group

OBJECTIVES

To compare the safety and tolerability of tamsulosin 0.4 mg once daily in younger (< 65 years) and older (> or = 65 years) patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic obstruction (BPO).

METHODS

In a retrospective analysis of two European double-blind, randomized, placebo-controlled trials, safety was assessed in 574 younger or older patients treated with tamsulosin or placebo for 12 weeks.

RESULTS

The incidence of adverse events, drug-related adverse events, serious adverse events and discontinuations due to adverse events was similar in older and younger tamsulosin-treated patients and was not significantly different from placebo. Although abnormal ejaculation was slightly more common in younger than older men receiving tamsulosin, the difference was not statistically significant from the placebo groups in both age groups. The incidence of adverse events possibly associated with vasodilation in tamsulosin-treated younger and older patients was 8.4 and 4.2%, respectively; these were comparable with the values for placebo-treated patients: 7.5 and 6%, respectively. Baseline systolic blood pressure was higher in older than younger patients, but there were minimal changes in blood pressure or pulse rate in tamsulosin- or placebo-treated patients in either age group.

CONCLUSIONS

Tamsulosin is well tolerated and suitable for use in older and younger patients with LUTS suggestive of BPO (symptomatic BPH).

Influence of pudendal nerve blockade on stress relaxation in the female urethra

The urethral pressure decay following a sudden and sustained dilatation corresponds to stress relaxation. Urethral stress relaxation can be described by the equation Pt = Pequ + P alpha e-t/tau alpha + P beta e-t/tau beta, where Pt is the pressure at time t, Pequ is the equilibrium pressure after dilatation, P alpha and P beta are pressure decay, and tau alpha and tau beta are time constants. The time constants have previously proved independent of the way the dilatation is performed. The urethral stress relaxation obtained in 10 healthy women before and after pudendal nerve blockade was analysed by the mathematical model and the pressure parameters and time constants determined. The fast time constant, tau beta, was reduced by the nerve blockade, whereas tau alpha was unaffected, however, both P alpha and P beta were reduced. No single stress relaxation parameter can therefore be related to the muscle or the connective tissue components. The method may prove useful in the further evaluation of the closure function of the urethra with special reference to the pathophysiology of stress urinary incontinence.

The urethral resistance to rapid dilation: an analysis of the effect of autonomic receptor stimulation and blockade and of pudendal nerve blockade in healthy females

The urethral closure function is based upon permanently as well as adjunctively acting closure forces during rest and stress episodes, respectively. During urine ingression intra- and peri-urethral structures are suddenly stretched resulting in a pressure response which strengthens the closure function by sustaining the resistance to dilatation of the urethra. A method for measurement of the resistance to rapid urethral dilatation was used to evaluate the influence of noradrenaline, prazosin, terbutaline, propranolol, carbachol, and atropine, as well as bilateral pudendal nerve blockades in 40 healthy women. The drugs caused no significant change in the urethral resistance to dilatation, whereas the pudendal blockade produced a significant (p < 0.05) reduction at the bladder neck and in the high pressure zone. Although a quantitative assessment of their contribution cannot be obtained from this study, it may be concluded that the striated muscles innervated by the pudendal nerve are of major importance for the urethral resistance to dilatation.

Passive urethral resistance to dilation in healthy women: an experimental simulation of urine ingression in the resting urethra

The dynamic urethral pressure response to a simulated urine ingression was studied at the bladder neck, in the high pressure zone, and in the distal urethra in 10 healthy female volunteers. The pressure response was characterised by a steep pressure increase simulataneous with the urethral dilation, followed by a decay during the next seconds until a new equilibrium pressure was reached. The pressure decay could be described by a double exponential function in the form Pt = Pequ + P alpha e-t/tau alpha + P beta e-t/tau beta, where Pt represents the pressure at the time t, Pequ represents the pressure at equilibrium, P alpha and P beta express the decline in pressure, and tau alpha and tau beta are time constants. The size of the pressure response proved highly dependent on velocity and size of dilation as well as urethral site of measurement, with the maximum values in the high pressure zone. The time constants, on the other hand, were uninfluenced by these factors. The pressure response represents an integrated stress response from the surrounding tissues which may reflect the visco-elastic properties of the structures involved. The findings indicate that striated muscle fibres are of dominating significance for the pressure response, and the varying size of the response along the urethra is in accordance with the localization of the horseshoe-shaped rhabdosphincter, which quantitatively is the dominating circularly arranged structure around the female urethra. Functionally, the stress response will oppose any dilation, and increasingly with rising size or velocity of dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of bilateral pudendal blockade on the adjunctive urethral closure forces in healthy females

The effect of bilateral pudendal blockade on the urethral pressure and power generation during coughing and pelvic floor squeezing was evaluated in 10 healthy women. The measurements were carried out at the bladder neck, in the high pressure zone, and distally in the urethra before and after blockade. Strong adjunctive closure forces were demonstrated all along the urethra. They were significantly reduced by pudendal blockade except at the bladder neck during coughing. The results indicate that the pudendal innervated striated muscles contribute significantly to the adjunctively acting closure forces all along the female urethra, including the bladder neck. Some passive pressure transmission to the bladder neck seems to take place during stress episodes following pudendal blockade, but whether it occurs in healthy females remain uncertain. The findings following pudendal blockade, corroborate with those in stress incontinent women, and thereby support the concept that striated muscle weakness is of pathophysiological significance in stress urinary incontinence.

The effect of pharmacological stimulation and blockade of autonomic receptors and of pudendal blockade on urethral stress relaxation in healthy women

OBJECTIVE

To examine the influence of autonomic receptor stimulation and blockade (noradrenaline, prazosin, terbutaline, propranolol, carbachol and atropine), and of pudendal nerve blockade on urethral stress relaxation.

SUBJECTS AND METHODS

Forty healthy women were evaluated. The stress relaxation parameter was defined as the relative rate of pressure decrease during a fixed period of time following a rapid dilatation of the urethra. The dilatation was performed by water-infusion into a small rubber cylinder placed in the urethra.

RESULTS

The drugs did not affect stress relaxation significantly, whereas the pudendal blockade produced a significant change along the length of the urethra characterized by a faster pressure decay following dilatation.

CONCLUSION

In women, stress relaxation in the urethra relies significantly on the pudendal nerve-innervated striated muscles.

Characterization of pressure changes in the lower urinary tract during coughing with special reference to the demands on the pressure recording equipment

The exact demands on urodynamic equipment for measurement of coughs and cough associated pressure changes in the lower urinary tract have been analyzed from high-speed pressure recordings using a double microtip transducer and a storage oscilloscope. The equipment was tested in vitro by the step-test method. The natural frequency response was 175.6 Hz and the rise-time 2.5 ms, resulting in accurate measurements of frequencies up to about 60 Hz, which is way above the clinically measured frequencies. Four men and 2 women, all of whom were healthy volunteers, were examined in the supine position with an empty bladder. Pressures were measured in the bladder and in the external sphincter zone of the urethra. The spectral power density of the bladder and urethral pressures were calculated by Fourier analysis. The pressure changes in the urethra were in all volunteers equal to or slower than in the bladder. The analysis of the spectral power density showed that 99% of the pressure changes could be recorded with an instrument capable of recording 9 Hz frequencies, i.e., with a sampling rate of 18 Hz or more.

The effect of pharmacological stimulation and blockade of autonomic receptors on the urethral pressure and power generation during coughing and squeezing of the pelvic floor in healthy females

The effect of autonomic receptor agonists and antagonists on the urethral pressure and power generation during coughing and squeezing of the pelvic floor has been evaluated in 30 healthy females. The measurements were carried out at the bladder neck, in the high pressure zone, and distally in the urethra. The used drugs (noradrenaline, prazosin, terbutaline, propranolol, carbachol and atropine) caused no significant change in the pressure and power generation. The clinically relevant influence of drugs on the urethral closure function should be re-appraised when based on profilometry in the resting state. The results support that the effect of the autonomic nervous system on the urethral closure function is insignificant in healthy women. They furthermore indicate that investigations on the ability to secure continence cannot be based solely on resting pressure profilometry, but should be accomplished by measurements during stress episodes.

In vivo evaluation of visco-elasticity in a biological tube. Part 2. Application of a mechanical model

Based on a theoretical model, the urethral stress-relaxation response following a sudden forced dilatation was studied in ten healthy female volunteers. The energy dissipation following a sudden urethral dilatation proved to follow the function Y = Z + C alpha e-t/tau alpha + C beta e-t/tau beta. Hence, a mechanical model was chosen, consisting of two Maxwell elements and one Hooke element coupled in parallel. The decay in force following deformation may be described as F = F(o) exp (-t.E/eta) for each Maxwell element. Thus, it was possible to determine the elastic E and viscous eta coefficients for the participating mechanical equivalents in the model, and thereby quantitatively describe the visco-elastic properties in the urethra. The reproducibility of the elastic and the viscous coefficients proved to be fairly high, and they seemed to be unaffected by the size of dilatation. On the other hand, the rate of dilatation clearly influenced the computed parameters. However, this phenomenon was easily explained by the duration of the deformation, which allowed the viscous elements to move before any measurements were performed. The present method permits in vivo evaluation of the elastic and viscous properties of the urethra, as well as other accessible biological tubes, and may be of value in the description of normal physiological and pathophysiological behaviour of the structures studied.

In vivo evaluation of visco-elasticity in a biological tube. Part 1. Stress relaxation in the female urethra studied by cross-sectional area and pressure measurements

The urethral response to a sudden forced dilatation was studied by a mathematical analysis of the pressure response in ten healthy women. A total of 60 dilatations, using various sizes and velocities of deformation, were performed in the high-pressure zone. The decay in pressure during relaxation proved to follow an exponential equation of the following form: Y = Z + C alpha e-t/tau alpha + C beta e-t/tau beta, where Z is the equilibrium pressure, C alpha and C beta are pressure decay, and T alpha and T beta are time constants. The time constants were unaffected by the circumstances of dilatation, whereas all the other parameters were correlated to size or velocity of dilatation, or both. The time constants showed a fairly high reproducibility when repeated after one weak. The method is presumed to characterise the tissue composition of the periluminal tissue layers and may prove useful in the evaluation of the normal urethral sphincter function. Furthermore, it may prove of value in the elucidation of the pathophysiology of stress urinary incontinence.

The dynamic pressure response to rapid dilatation of the resting urethra in healthy women: an in vivo evaluation of visco-elastic properties

The urethral pressure response to a sudden forced dilatation was studied at the bladder neck, in the high-pressure zone and in the distal urethra in ten healthy female volunteers. The pressure response was fitted with a double exponential function of the form Pt = Pequ + P alpha e-t/tau alpha + P beta e-t/tau beta, where Pequ, P alpha and P beta are constants, and tau alpha and tau beta are time constants; this equation has previously been demonstrated to describe the pressure decay following dilatation. On the basis of a theoretical model the elastic and viscous constants for the urethral tissues were computed. The results showed significant differences along the urethra, with the high-pressure zone showing the highest maximum and equilibrium pressures, fastest pressure decay and highest elastic coefficient. The pressure response represents an integrated stress response from the surrounding structures, which reflects the visco-elastic properties of the tissues involved. The findings seem therefore to correlate well with the anatomical findings, which have shown a high fibre density of the horseshoe-shaped rhabdosphincter in the mid-portion of the urethra. The method permits a detailed assessment of static and dynamic urethral responses to dilatation which can be applied as an experimental simulation of urine ingression, and is therefore presumed to be of value in the evaluation of normal and pathological urethral sphincter function.

The influence of beta-adrenoceptor and muscarinic receptor agonists and antagonists on the static urethral closure function in healthy females

The effects of terbutaline, propranolol, carbachol, and atropine on the static urethral closure function were investigated in 20 healthy women. Terbutaline caused a statistically reduction of the urethral pressure in the high pressure zone, but not at the bladder neck or in the distal urethra. The other drugs caused no significant pressure changes. None of the drugs used produced significant changes in the static viscoelastic properties, elastance, and hysteresis of the resting urethra. It is suggested that terbutaline partly reduces intraurethral pressure by reducing muscular tone in the rhabdosphincter and pelvic floor.

The dynamic urethral sphincter function in healthy females assessed by rapid dilatations in the resting state: evaluation of reproducibility

Recording the pressure response to rapid dilatations enables one to assess urethral sphincter function. The rapid dilatations of the urethra experimentally simulate the ingression of urine. A method that enables standardized dilatations of 2-mm long urethral segments was urine (USED).A method that enables standardized dilatations of 2-mm long urethral segments was used, and the subsequent pressure response was measured. The reproducibility of the urethral pressure response to rapid and standardized dilatations was evaluated by repeating the measurements after 1 week in 10 healthy females. The pressure response showed an acceptable reproducibility. The urethral pressure increase as a response to dilatation is considered to rely on stretching of intra- and periurethral fibers. Calculations of strain (change in length divided by the original length) of circularly arranged fibers when the urethra is dilated indicate that the tension (and pressure) bearing layers must be located outside a circular zone with a radius of 4 mm perpendicular to the longitudinal axis of the urethra.

The effect of bilateral pudendal blockade on the static urethral closure function in healthy females

OBJECTIVE

To evaluate the effect of bilateral pudendal blockade on the urethral closure function in the resting state in healthy women.

METHODS

Synchronous measurements of pressure and cross-sectional area were recorded at the bladder neck, in the high-pressure zone, and in the distal urethra before and after the pudendal blockade in ten women.

RESULTS

The blockade reduced the resting pressure significantly (P < .01) all along the urethra. The viscoelastic indices of elastance (reciprocal of compliance) and hysteresis (difference in pressure at a given degree of urethral dilation when this is increased and decreased stepwise) were significantly (P < .05) reduced.

CONCLUSIONS

The striated muscles innervated by the pudendal nerve are of paramount importance for the closure function in the resting state all along the urethra. Urethral elastance and hysteresis seem to depend on activity in the surrounding striated muscle fibers.

Pressure response to rapid dilation of resting urethra in healthy women

Rapid urethral dilations were performed by a balloon mounted on a double-tip transducer catheter for simultaneous measurement of pressure in urethra and bladder. The cross sectional area of the urethra was measured according to the field gradient principle. Pressure and cross sectional area were recorded synchronously. The response of the female urethra to rapid dilation is a typical stress relaxation effect with a pressure peak followed by a pressure decay over a few seconds. The peak pressure response represents the bladder pressure required in producing a corresponding urethral dilation by the ingression of urine. The increase in pressure response was statistically significant by increasing rate as well as size of dilation. The method enables experimental simulation of stress urinary incontinence in vivo which may bring further insight into the physiology of the urethral closure function and the pathophysiology of stress incontinence. For comparative studies rapid dilation should be performed under standardized circumstances.

Urethral pressure--which one?

Urethral pressure was investigated by a method which allowed simultaneous measurement of the cross-sectional area. In healthy women a pressure range of 25-140 cm H2O was recorded at one urethral site as a response to the circumstances under which the measurement was performed. The pressures obtained were related to the degree of urethral distension and to the time after the change in distension. Measuring urethral pressure at one specific degree of distension results in one specific pressure value according to the dimensions of the measuring probe. However, this specific pressure value cannot be considered to supply more information on urethral sphincter function than any other pressures included in a range which can be obtained by changing the circumstances under which the measurement are carried out. More provocative methods of pressure measurement which simulate some of the physiological conditions of the urethra may provide more information on sphincter efficiency.

Initial urethral pressure increase during stress episodes in genuine stress incontinent women

The urethral and bladder pressure increments registered during a cough were investigated in 30 woman with genuine stress incontinence (GSI) and compared with those from 30 previously investigated healthy women. The pressures were measured by means of a double microtip transducer catheter with the bladder sensor uncovered and the urethral sensor covered with a water-filled rubber cylinder and placed at the bladder neck, midurethrally, or distally in the urethra. In GSI women the pressure increment preceding the pressure spike produced by coughing was significantly higher in the bladder compared with the urethra, and the pressure increment seemed to be initiated in the bladder and all along the urethra simultaneously. In healthy women the pressure increment preceding a pressure spike was significantly higher in the midurethra compared with the bladder and it seemed to be initiated in the midurethra. These findings seem to reflect a defective active closure mechanism in GSI which may be a contributing factor in its pathogenesis.

The effect of alpha-adrenoceptor stimulation and blockade on the static urethral sphincter function in healthy females

The influence of noradrenaline and prazosin on the urethral closure function was evaluated in 10 healthy female volunteers. Measurements of pressure at varying cross sectional areas were carried out at the bladder neck, in the high pressure zone, and in the distal urethra. Prazosin reduced the static pressure, predominantly in the midportion of the urethra, whereas noradrenaline caused no significant pressure change. The urethral resistance to dilatation and the hysteresis were unaffected by the two agents. It is suggested that the response to prazosin is related to decreased activity of the urethral smooth as well as of the striated muscles, the latter as a result of a reduced somatomotor output from the central nervous system.

Stress relaxation phenomenon in the healthy female urethra

Following dilatation, urethral pressure declines over the next few seconds to a state of equilibrium. The stress relaxation parameter, Pt0.5, was defined as the relative pressure decrease 0.5 s after dilatation, where the pressures at 0.1 s and at the new equilibrium were set to 100% and 0% respectively. Pt0.5 was calculated from 171 urethral dilatations performed at each of 3 urethral sites of measurement in 10 healthy volunteers. It was found to be independent of the rate and size of urethral dilatation. It showed a fairly high reproducibility rate when repeated after 1 h and 1 week. Pt0.5 was calculated to approximately 60% with no variation along the urethra. The parameter is assumed to be useful in evaluating urethral sphincter function. Although the method can be performed without special urodynamic equipment, the frequency response of the pressure measurement system must be adequate.

Urethral stress relaxation phenomenon in healthy and stress incontinent women

Urethral stress relaxation was induced by sudden forced dilatation. The stress relaxation parameter, Pt0.5, was defined as the relative pressure decrease 0.5 s after dilatation, where the pressures at 0.1 s and at the new equilibrium were set to 100% and 0% respectively. Pt0.5 was calculated in 28 healthy and 30 women with genuine stress incontinence. Measurements were performed at the bladder neck, in the high pressure zone and in the distal urethra. The measurements showed that all along the urethra, Pt0.5 was statistically significantly greater in the healthy women than in the incontinent women, the greatest difference being found at the bladder neck. Although there was a slight overlap in values between the 2 groups, this parameter seems useful in differentiating between competent and incompetent urethral sphincters.

How to measure urethral elastance in a simple way. Elastance: definition, determination and implications

The elastance of a biological tube describes the resistance of the latter to dilatation. It is defined as dP/dV, where dP is the pressure increase caused by the volume increase dV. Elastance is the reciprocal of compliance. Elastance in the female urethra can be estimated from the slope of the regression line of related values of pressure and cross-sectional area. In the present study, urethral elastance was calculated by measurement of the related pressures and cross-sectional areas during stepwise dilatation by a balloon and by determination of the pressure at which inflow through side holes in catheters with increasing diameters began. There was no difference between the elastance values obtained by the two methods. Due to the linear correlation found between pressure and cross-sectional area we conclude that urethral elastance can be estimated from measurements of urethral pressure at two or more related cross-sectional areas by a simple technique using e.g., 8F, 14F, and 20F catheters.

Method for evaluation of the urethral closure mechanism in women during standardised changes of cross-sectional area

A method for evaluation of the closure mechanism in the female urethra during forced opening has been developed and tested. The cross-sectional area (CA) of the tube and the intraluminal pressure were measured simultaneously by a specially designed balloon catheter. The method enables induction of standardised changes of CA at different rates. Applied in the female urethra the induction results in a distinct pressure response which increases with increasing rate of change of CA as well as size of the induction. The inflation of the balloon simulates a forced opening of the urethra and hence leakage. Obviously, urinary incontinence takes place at forced opening of the urethra. Accordingly, this novel method can give important information on the pathophysiology of stress urinary incontinence in particular and the physiology of sphincter functions in general.

Variations in urethral and bladder pressure during stress episodes in healthy women

Pressure variations in the urethra and bladder during stress episodes and their time separations were investigated in 30 healthy female volunteers. The pressure was measured by means of a double microtip transducer catheter with the distal sensor in the bladder and the proximal sensor at the bladder neck, the mid-urethra and the distal urethra. In advance of the pressure spike during cough a pressure rise was demonstrated in the bladder and at all 3 sites of measurement in the urethra. The urethral pressure increments preceding and following the pressure spike were statistically significantly higher in the mid-urethra than the corresponding bladder pressures. This active urethral pressure generation in the mid-urethra and distal urethra was initiated 200 ms before the bladder pressure began to rise. The pressure in the urethral high pressure zone was higher than the bladder pressure in all cases. Passive pressure transmission to the urethral high pressure zone can take place only insignificantly due to a continuous higher pressure inside the urethra than in the bladder and due to the location of the high pressure zone in the demarcation of the abdominal cavity. It was concluded that the urethral pressure rise in the high pressure zone during stress episodes is mainly generated actively by intra- and/or peri-urethral structures.

Is micturition disorder a pathogenic factor in acute epididymitis? An evaluation of simultaneous bladder pressure and urine flow in men with previous acute epididymitis

We evaluated 22 men 22 to 70 years old with previous acute epididymitis by pressure-flow study 3 to 12 months after the inflammation had resolved. Nine healthy men 20 to 62 years old were evaluated as controls. The patients had no symptoms from the lower urinary tract except for 2 men with slight prostatism. The maximum intravesical and maximum voiding pressures were elevated significantly in the patients compared to the controls (p less than 0.05). In most patients and in all of the controls the maximum urinary flow rates were within the normal range according to age. Because of the frequency of high voiding pressures in patients with previous acute epididymitis, this condition may be a pathogenic factor by promoting urethrovasal reflux. The high voiding pressures may be transmitted to the proximal urethra or in cases of a narrow and rigid bladder neck they may produce increased turbulence in the urine stream.

The analgesic effect of indomethacin in the early post-operative period following abdominal surgery. A double-blind controlled study

Patients undergoing major intra-abdominal operations were randomly allocated to receive either 100 mg indomethacin (n = 26) or placebo (n = 20), both given as suppositories, 3 times a day for 3 days. The analgesic effect of indomethacin was measured during the first 5 post-operative days by grading the experience of pain on a closed visual analogue pain scale and further by registration of the amount of narcotics requested. Patients receiving indomethacin had significantly lower pain scores and received significantly fewer doses of narcotics (p less than 0.01). There were only minor side effects which were equally frequent in the 2 groups. These results indicate that indomethacin is an effective analgesic drug in the early post-operative period.