bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time constants in force development and force recovery in smooth muscle
Authors: Van Mastrigt R. 
Published: March 2007

AbstractThe isometric force development of pig urinary bladder smooth muscle strips in response to electrical stimulation and the force recovery following quick release of fully activated strips were characterized by a set of three time constants. The slowest time constant in the order of 2.2 s characterizes the intracellular calcium release in the excitation‐contraction coupling process. The second time constant was in the order of 0.45 s and could be related to cross‐bridge cycling, whereas the fastest time constant in the order of 0.032 s was ascribed to passive viscoelastic processes in the cross‐bridges.
Impact of changes in posture and bladder filling on the mechanical properties of the urethra in healthy and stress‐incontinent females
Authors: Lose Gunnar 
Published: March 2007

AbstractA pressure/cross‐sectional area probe was used to examine the impact of changes in posture and bladder filling on the mechanical properties of the urethra in 29 healthy females and in 28 patients with genuine stress incontinence (GSI). Measurements were performed at the bladder neck, in the high‐pressure zone, and distally in the urethra.When changing posture from supine to standing position the urethral pressure at the bladder neck and midurethrally increased statistically significantly (P>0.01) in both groups. The urethral pressure increase was most pronounced in the midurethra which indicates that active muscle contraction is involved. Maximum urethral closure pressure was unchanged in the control group while it decreased statistically significantly (P>0.01) in the GSI group. Urethral elastance increased midurethrally in healthy women while it decreased in GSI women in the upright posture. Although these changes were not statistically significant, elastance was statistically significantly higher midurethrally in the erect position in the control group. These findings indicate impaired striated muscle function in or around the urethra in GSI women.Filling the bladder to 50% of the functional capacity did not change any urethral parameter in the two groups of women. The wide divergency in previously reported results is discussed.
Pelvic floor muscle exercise for the treatment of female stress urinary incontinence: I. Reliability of vaginal pressure measurements of pelvic floor muscle strength
Authors: Bø Kari , Kvarstein Bernt , Hagen Rolf , Larsen Stig 
Published: March 2007

AbstractThe reliability of measurements of pelvic floor muscle strength using a vaginal balloon catheter connected to a pressure transducer was tested in 28 healthy women, mean age 32.3 years (21–50).Fourteen women (group 1) performed three pelvic floor muscle contractions in three series with reinstallation of the balloon catheter to the same vaginal position between each series. Additionally, retest was done after a period of 2 weeks. Reproducibility of the results was tested in another similar group of 14 women (group 2) who did a 1 day test.In the first group the maximum contraction value (resting pressure not included) varied from 5 to 40 cm H2O. However, the median difference value of the three series tested on two different days was only 3, 1, and 1 cm H2O, respectively. The two groups of women demonstrated similar values of vaginal pressure measurements. Thus, a balloon with a given vaginal position for measurements of pelvic floor muscle strength gives reliable pressure recordings.
Pelvic floor muscle exercise for the treatment of female stress urinary incontinence: III. Effects of two different degrees of pelvic floor muscle exercises
Authors: Bø Kari , Hagen Rolf H. , Kvarstein Bernt , Jørgensen Jan , Larsen Stig , Burgio Kathryn L. 
Published: March 2007

AbstractFifty‐two women, mean age 45.9 years (24–64) with clinically and urodynamically proven stress urinary incontinence (SUI) were randomly assigned to one of two different pelvic floor muscle (PFM) exercise groups. Both groups performed 8–12 maximal PFM contractions 3 times a day for 6 months. In addition one group exercised with an instructor intensively 45 min once a week performing long‐lasting contractions with the supplement of 3–4 fast contractions at the end of each long‐lasting contraction.Initially and after 6 months an examination was performed comprising history, urinary leakage index, pad test, maximum urethral closure pressure, functional urethral profile length, and recording of vaginal pressure during PFM contractions. The latter was performed monthly.After the treatment 60% of the intensive exercise (IE) group and 17.3% of the home exercise (HE) group reported to be continent or almost continent (P < .01). Only the IE group demonstrated significant reduction in urine loss; from mean 27 g to 7.1 g (P < .01) and improvement in maximum resting urethral closure pressure (mean improvement 4.6 cm H2O. P = .02). PFM strength improved with mean 15.5 cm H2O (P < .01) in the IE group while the HE group improved with 7.4 cm H2O (P < .01).It is concluded that the results of PFM exercise for female SUI is highly dependent upon the degree and duration of treatment and frequent supervision by the therapist.
Changes in bladder function following a surgical alteration in outflow resistance
Authors: Pope A. J. , Shaw P. J. R. , Coptcoat M. J. , Worth P. H. L. 
Published: March 2007

AbstractThe changes in bladder function occurring after a surgical alteration in bladder outflow resistance were studied in 20 males undergoing transurethral prostatectomy (TURP) and in 20 females undergoing an endoscopic bladder neck suspension (EBNS). Serial cystometrograms (CMG) were performed before operation, and on alternate days after spontaneous micturition was re‐established, for 5 days in the males and for 21 days in the females. CMGs were repeated at 3 months and 1 year after operation.After TURP voiding pressures (Pdet) fell rapidly from a mean of 118 cm H2O before operation to 57 cm H2O at 5 days, with an increase in flow rate during this time from 10.5 ml/s to 24 ml/s. Detrusor instability that had been present in 14 patients resolved within 2 days in 12. There was no further significant urodynamic change over the 1‐year study period.After EBNS, there was an early rise in voiding pressure (Pdet rose from 26 cm H2O before operation to 42 cm H2O at 3 days). This continued to increase up to 21 days particularly in those patients with initial large residuals. Three patients developed detrusor instability. Flow rates were greatly reduced at first (27 ml/s before operation and 13 ml/s at 3 days), and gradually increased in line with voiding pressures, yet were still diminished 1 year after operation.The urodynamic changes following a reduction in bladder outflow resistance by TURP are immediate and sustained and unlikely to be the result of structural changes within the bladder wall. EBNS produces an increase in outflow resistance and it can be several weeks before balanced voiding is achieved, with significantly increased detrusor pressures needed to achieve complete bladder emptying at a reduced flow rate.
Psychophysical functions of the sensation evoked by electrical stimulation of the posterior urethra
Authors: Hansen Michael V. 
Published: March 2007

AbstractFollowing electrical stimulation of the posterior urethra, visceral afferent nerves are excited that transmit sensory information perceived as an imminent desire to void. In the present study, some basic psychophysical relations involved in the sensations evoked this way were investigated. The results included the following. First, in the temporal integration relation, the relation between the sensory threshold (sT) and the duration of the stimulus (D) followed a power function: sT*DK = m, in which K and m are constants. Second, in 20 healthy subjects, the sensory threshold determined with increasing strength (sTi) and determined with decreasing strength (sTd) were linearly correlated (P≤0.001). The slope of the relations between sTi and sTd decreased with the duration of stimulus. Third, the sTi and sTd were inversely related to the frequency of the stimulus. Fourth, the relation between the mean reaction time (RT) and the stimulus strength (I) followed a significant power function fit after stimulation in the posterior urethra (R = 0.93, P≤0.001): RT = ∂ * I−n, in which ∂ and n are constants. Finally, stimulation of the penile skin either electrically, with vibration or with a cold stimulus, caused a significant increase in the sensory thresholds determined in the posterior urethra. The conclusion of the study was that sensations evoked by electrical stimulation of visceral afferent pathways in the posterior urethra follow psychophysical power functions similar to those of exteroceptive sensory modalities.
Transurethral nervi erigentes stimulation: An experimental study in the dog
Authors: Hashmat A. , Vega A. Luna 
Published: March 2007

AbstractAn erection obtained during external sphincterotomy on a paraplegic patient prompted this experiment in an animal model. Four dogs were anesthetized and a transurethral electrical current was used to stimulate the cavernosus nerves and obtain a penile erection. The erectile response was assessed by measurement of the girth of the glans before and after stimulation. There was an increase of 2 cm in the girth of the glans and the penis became firm and remained erect while being stimulated.The aim of the experiment was to elucidate another technique to assess the integrity of the nervous pathway for erection. Transurethral stimulation of nervi erigentes may be used also as a tool to investigate erectile dysfunction.The stimulated erection observed in a paraplegic patient after transurethral electrical stimulation confirms previous observations that the erectile mechanism is maintained in paraplegic patients, with an intact thoracolumbar sympathetic outflow.
Urodynamic changes in women using diaphragms
Authors: Ramahi Alfida J. , Richardson David A. 
Published: March 2007

AbstractAlthough the diagphragm is widely used as a method of contraception, little is known as to its effect on urethrovesical function. To evaluate whether the diaphragm, or diaphragm size, influences bladder function, urodynamic studies were performed in nine nulliparous volunteers. Maximum and mean flow rates were significantly decreased with diagphragm use (P>0.02). Urethral resistance was significantly increased with both diaphragm sizes compared to control values (P>0.02). There were no significant changes in urethral functional length, closure pressure, and pressure transmission ratio between the diaphragms and control. Although there were statistically significant differences in urodynamic results, no strong evidence for urethral obstruction was found with diaphgram usage.
Distal urethral compensatory mechanisms in women with an incompetent bladder neck who remain continent, and the effect of the menopause
Authors: Versi Eboo , Cardozo Linda , Studd John , McGuire Edward , Versi E. , Cardozo L. D. 
Published: March 2007

AbstractFemale continence is thought to be maintained at the level of the bladder neck and by the external sphincter. However, many women have an incompetent bladder neck, that is their bladder neck opens under stress. However, they still remain continent, presumably by use of their distal external sphincter. To establish the effect of age and the menopause on this phenomenon, data from 202 climacteric urodynamically normal and continent women were examined. The overall prevalence of videocystourethographically diagnosed bladder neck incompetence in these women was 51 ± 4%. The median age in this group was 50.4 years but the prevalence of bladder neck incompetence in women below 50.4 years was not significantly different from older women (>50.4 years) being 49 ± 5% and 53 ± 5%, respectively. Of the 202 women studied the prevalence of bladder neck incompetence in perimenopausal women was 54 ± 5% and 48 ± 5% in postmenopausal women, there being no statistically significant difference between the two subgroups separated on the basis of their estrogen status. These data do not support the contention that bladder neck integrity is estrogen dependent nor is there any evidence from these data that is it age dependent. To understand how women with bladder neck incompetence maintain continence, 55 of the 202 women also underwent urethral pressure profilometry. Bladder neck incompetence results in a proximal shortening of the stress urethral pressure profile but these women maintained their stress urethral functional length by decreased distal shortening of the stress profile. In other words, they made more use of the distal portion of the urethra. This is achieved by augmentation of their distal transmission pressure ratios.
Ontogeny of bladder compliance
Authors: Zderic Stephen A. , Duckett John W. , Snyder Howard M. , Wein Alan J. , Levin Robert M. 
Published: March 2007

AbstractRecent advances in technology have allowed for the diagnosis of many urologic abnormalities through the use of antenatal ultrasonography. There is great debate in the pediatric literature as to whether the hydronephrosis which is diagnosed via antenatal ultrasound is always secondary to obstruction, or in certain cases represents a benign dilatation. Benign dilatations are postulated to be secondary to the increased fetal diuresis and a more compliant fetal urinary tract. In this study we present evidence for a gradual decline in bladder compliance with maturation. A summary of our results demonstrates that bladders obtained from 1 day old rabbits are 2 and 3 times more compliant than bladders of 4–8 week old rabbits. Active tension reaches a peak when the muscle is stretched to 150% of its initial resting length. However, 1 day old bladder tissue exhibits a higher active tension in response to field stimulation when compared to the response of bladder tissue obtained from 4 and 8 week old rabbits. In summary, compliance and active tension decrease with maturation.
Parameters of detrusor contractility: I: The effects of electrical stimulation, hysteresis, and bladder volume in an in vitro whole rabbit bladder model
Authors: Kaplan Steven A. , Blaivas Jerry G. , Brown William C. , Levin Robert M. 
Published: March 2007

AbstractThis study represents the first of a five phase project which was designed to develop parameters to assess detrusor contractility and urethral obstruction. The first phase was designed to (1) determine the optimal volume at which to measure various parameters of detrusor contractility and (2) determine the effects of hysteresis on isovolumetric detrusor pressure (Piso). To this end, the bladders of five male white New Zealand rabbits were isolated and placed in a bath chamber. Intravesical pressure and the weight of the voided urine were monitored by a pressure transducer and electronic balance, respectively. Bladder capacity ranged between 41 ml and 53 ml (mean 47 ± 2.34). In the first phase of this experiment, Piso was determined at 1, 2.5, 5, 10, and 20 ml. Piso was always found at a volume of 2.5 ml (20.7 ± 2.86). There was a 13% decrease in Piso at 1 and 5 ml, a 35% decrease at 10 ml, and a 49% decrease at 20 ml. This was significant at P < 0.05.In the second part of the experiment, the effect of different methods of filling on the magnitude of subsequent isometric contractions was examined. It was found that preceding strain (hysteresis) had no effect on subsequent contractions. In addition, the average Piso for each volume remained the same regardless of the method of filling.In conclusion, these data suggest that the effect of hysteresis and method of bladder filling on Piso was negligible. In addition, as one would expect from the geometric configuration of the bladder, maximum detrusor pressure occurred at relatively low bladder volumes, i.e., less than 5% capacity. Further research is in progress to determine which parameters are important in delineating and predicting bladder performance.
Impaired bladder contractility in association with detrusor instability: Underestimated occurrence in benign prostatic hyperplasia
Authors: Ghoniem Gamal M. 
Published: March 2007

AbstractThe hyperactive bladder does not always completely empty. The aim of this study was to determine the frequency of detrusor instability and impaired contractility in 45 patients with benign prostatic hyperplasia. The evaluation consisted of uroflowmetry, residual urine determination, cystometrogram (CMG), and micturition study with stop‐flow technique. Detrusor instability is diagnosed urodynamically with the appearance of abnormal contractions either on medium filling CMG and/or on a provocative rapid injection CMG. Impaired bladder contractility was diagnosed by the presence of significant residual urine (≥50% of capacity) and unsustained bladder contraction with no or little detrusor reserve power. Urodynamic evaluation showed that 21 out of 45 patients had detrusor instability. Seven of these patients showed also impaired contractility. The mean residual urine was 380 ml in this subgroup. On micturition studies five of these patients showed low pressure, low uroflow pattern. Stop‐flow technique revealed absence of detrusor reserve power in five patients, while two patients showed little detrusor reserve power. Out of the 24 patients with stable bladders, four showed impaired contractility. Indeed, detrusor instability is not associated exclusively with low residual urine values. The importance of recognizing detrusor instability in combination with poor contractility in patients with benign prostatic hyperplasia is that one can anticipate incomplete bladder emptying even after protstate surgery and consider other forms of therapy. Our approach to this specific problem is presented.
Detrusor behavior in patients with dominant hemispheric strokes
Authors: Badlani Gopal H. , Vohra Sanjeev , Motola Jay A. 
Published: March 2007

AbstractThe urodynamic evaluations of 44 consecutive stroke patients were evaluated retrospectively. The results were evaluated with regards to the location of the cerebrovascular accident. Urodynamic findings could not be characterized by the site of the cerebrovascular injury sustained. In this retrospective study, we were not able to define an influence of a dominant hemispheric stroke upon future bladder function.
Detrusor hyperreflexia and its relationship to posterior bladder neck sensor mechanism in spinal injured patients
Authors: Perkash Inder , Wolfe Vickie 
Published: March 2007

AbstractThis report describes the existence of a sensor mechanism at the posterior bladder neck region which invokes bladder contraction in patients with detrusor hyperreflexia when stimulated mechanically with a transurethral catheter. Studies were monitored through transrectal linear array sonography to precisely localize the site stimulated with the tip of the catheter during urodynamic evaluation. The location of sensor mechanism is just distal to the trigone at the posterior bladder neck region and extends into the posterior urethra for 0.5 to 1 cm into the posterior urethra. Its clinical implications in female urge incontinence seem to agree with the “second sensor” described by Bradley in 1975 (Urology 6:654, 1975). The bladder neck sensor mechanism possibly facilitates normal progressive voiding and seems to exaggerate voiding in the hyperreflexic bladders.
Pressure/flow studies preoperatively and postoperatively in patients with benign prostatic hypertrophy: Estimation of the urethral pressure/flow relation and urethral elasticity
Authors: Spångberg Anders , Teriö Heikki , Ask Per , Engberg Anders , Griffiths Derek 
Published: March 2007

AbstractPressure/flow studies were performed in 28 men with benign prostatic hypertrophy. Twenty‐three of the men were also studied postoperatively. Urethral function during micturition was quantified by the urethral pressure/flow relation, pdet = pmo + Lm Qm, where Pdet is detrusor pressure, Pmo is minimal opening pressure. Q is flow rate, and m and Lm are parameters. Using this method to quantify urethral function, three urodynamically different types of obstruction can be defined. In the first of these, Pmo is elevated corresponding to Schäfer's compressive obstruction. The second is a constrictive type of obstruction in which m ≥ 4/3 and Lm is elevated and the third is a low‐compliant type of obstruction in which m ≤ 1 and Lm is elevated. The two latter types of obstruction may be combined with a compressive obstruction.The preoperative pressure/flow relations were mostly characterized by a very high Pmo, a moderately elevated Lm, and a low m. Thus the majority of patients had a combination of compressive and low‐compliant obstruction. Postoperatively, micturitions were much improved and the pressure/flow relations often had an even lower Pmo than normal, a normal Lm, and a high m.From the pressure/flow relations, the elasticity of the flow‐controlling zone can be estimated and described by the urethral pressure/area relation, p(A) = pmo + Kn An, where p(A) is the intrinsic urethral pressure, A is the cross‐sectional area of the flow‐controlling zone and Kn and n are parameters describing the distensibility of the flow‐controlling zone. Preoperatively, the flow‐controlling zone had a low distensibility. The shape of the curve suggested that the urethra could have been distended further by higher pressure. Postoperatively, the urethra was distended to larger cross‐sectional areas, but in many cases the shape of the curve suggested that distension was restricted by fibrosis. Median and range values for the model parameters as well as discriminating limits between the preoperative micturitions and micturitions in elderly men without voiding problems are presented.The exponent m is not perfectly reproducible but tends to be the same if a person performs several micturitions. The residual sum of squares is often increased more than 100% if an exponent m value other than the optimal one is used for curve fitting.Results when the micturitions were analysed with Schäfer's model and classified using the maximum flow/pressure at maximum flow diagram recommended by the Interenational Continence Society are also shown.
A pressure management system for the neurogenic bladder after spinal cord injury
Authors: McGuire E. J. , Noll F. , Maynard F. 
Published: March 2007

AbstractOne hundred eighteen patients consecutively admitted to a University Rehabilitation Program entered a protocol study of urologic management. Bladder pressures were kept below 30 cms/H2O by urologic treatment. Serial urodynamic, radiographic, bacteriologic, and endoscopic studies were performed at regular intervals. Eighteen patients have been lost to follow‐up; 100 patients were followed for a mean 25.4 months with a range of 6 months to 56 months. There were 105 patients with lesions superior to the sacral segments and 13 patients with low lesions. At discharge 11 patients were voiding normally, 105 were continent on an intermittent catheterization (IC) protocol, and 2 patients used condom catheter drainage following sphincterotomy. Bacterial cultures and urinalysis data showed little or no relationship to clinical outcome, and treatment for 387 weeks by antimicrobial agents was not associated with discernible benefit as opposed to no treatment. Five patients developed bladder calculi, and five developed unilateral epididymitis. Bladder pressure was relatively easy to control following spinal cord injury, a result which suggests that high bladder pressure is not a direct result of the neural injury, but rather an evolutionary change as a result of bladder and urethral interactive dysfunction.