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Concept: Urethra


BACKGROUND: To investigate the effect of prostaglandin depletion by means of COX-inhibition on cholinergic enhanced spontaneous contractions. METHODS: The urethra and bladder of 9 male guinea pigs (weight 270–300 g) were removed and placed in an organ bath with Krebs' solution. A catheter was passed through the urethra through which the intravesical pressure was measured. The muscarinic agonist arecaidine, the non-selective COX inhibitor indomethacin, and PGE2 were subsequently added to the organ bath. The initial average frequency and amplitude of spontaneous contractions in the first 2 minutes after arecaidine application were labelled Fini and Pini, respectively. The steady state frequency (Fsteady) and amplitude (Psteady) were defined as the average frequency and amplitude during the 5 minutes before the next wash out. RESULTS: Application of 1 muM PGE2 increased the amplitude of spontaneous contractions without affecting frequency. 10 muM of indomethacin reduced amplitude but not frequency.The addition of indomethacin did not alter Fini after the first application (p = 0.7665). However, after the second wash, Fini was decreased (p = 0.0005). Fsteady, Psteady and Pini were not significantly different in any of the conditions. These effects of indomethacin were reversible by PGE2 addition.. CONCLUSIONS: Blocking PG synthesis decreased the cholinergically stimulated autonomous contractions in the isolated bladder. This suggests that PG could modify normal cholinergically evoked response. A combination of drugs inhibiting muscarinic receptors and PG function or production can then become an interesting focus of research on a treatment for overactive bladder syndrome.

Concepts: Guinea pig, Urogenital sinus, Ureter, Urine, Urethra, Urology, Urinary system, Urinary bladder


Many urological studies rely on models of animals, such as rats and pigs, but their relation to the human urinary system is poorly understood. Here, we elucidate the hydrodynamics of urination across five orders of magnitude in body mass. Using high-speed videography and flow-rate measurement obtained at Zoo Atlanta, we discover that all mammals above 3 kg in weight empty their bladders over nearly constant duration of 21 ± 13 s. This feat is possible, because larger animals have longer urethras and thus, higher gravitational force and higher flow speed. Smaller mammals are challenged during urination by high viscous and capillary forces that limit their urine to single drops. Our findings reveal that the urethra is a flow-enhancing device, enabling the urinary system to be scaled up by a factor of 3,600 in volume without compromising its function. This study may help to diagnose urinary problems in animals as well as inspire the design of scalable hydrodynamic systems based on those in nature.

Concepts: Urination, Blood, Fluid mechanics, Urinary system, Urethra, Urine, Mass, Urinary bladder


Computed tomography urogram (CTU) is recommended when investigating patients with hematuria. We determine the incidence of urinary tract cancer and compare the diagnostic accuracy of CTU and renal and bladder ultrasound (RBUS) at identifying urinary tract cancer.

Concepts: Medical imaging, Hematuria, Urethra, Urinary system, Ureter, Kidney, Urine, Urinary bladder


BACKGROUND: Women presenting with symptoms of acute uncomplicated urinary tract infection (UTI) are often prescribed antibiotics. However, in 25 to 50% of symptomatic women not taking antibiotics, symptoms recover spontaneously within one week. It is not known how many women are prepared to delay antibiotic treatment. We investigated how many women presenting with UTI symptoms were willing to delay antibiotic treatment when asked by their general practitioner (GP). METHODS: From 18 April 2006 until 8 October 2008, in a prospective cohort study, patients were recruited in 20 GP practices in and around Amsterdam, the Netherlands. Healthy, non-pregnant women who contacted their GP with painful and/or frequent micturition for no longer than seven days registered their symptoms and collected urine for urinalysis and culture. GPs were requested to ask all patients if they were willing to delay antibiotic treatment, without knowing the result of the culture at that moment. After seven days, patients reported whether their symptoms had improved and whether they had used any antibiotics. RESULTS: Of 176 women, 137 were asked by their GP to delay antibiotic treatment, of whom 37% (51/137) were willing to delay. After one week, 55% (28/51) of delaying women had not used antibiotics, of whom 71% (20/28) reported clinical improvement or cure. None of the participating women developed pyelonephritis. CONCLUSIONS: More than a third of women with UTI symptoms are willing to delay antibiotic treatment when asked by their GP. The majority of delaying women report spontaneous symptom improvement after one week.

Concepts: Bacteria, Urinary bladder, Disease, Urethra, Antibiotic, Kidney, Urine, Urinary tract infection


Loss of bladder control is a challenging outcome facing patients with spinal cord injury (SCI). We report that systemic blocking of pro-nerve growth factor (proNGF) signaling through p75 with a CNS-penetrating small-molecule p75 inhibitor resulted in significant improvement in bladder function after SCI in rodents. The usual hyperreflexia was attenuated with normal bladder pressure, and automatic micturition was acquired weeks earlier than in the controls. The improvement was associated with increased excitatory input to the spinal cord, in particular onto the tyrosine hydroxylase-positive fibers in the dorsal commissure. The drug also had an effect on the bladder itself, as the urothelial hyperplasia and detrusor hypertrophy that accompany SCI were largely prevented. Urothelial cell loss that precedes hyperplasia was dependent on p75 in response to urinary proNGF that is detected after SCI in rodents and humans. Surprisingly, death of urothelial cells and the ensuing hyperplastic response were beneficial to functional recovery. Deleting p75 from the urothelium prevented urothelial death, but resulted in reduction in overall voiding efficiency after SCI. These results unveil a dual role of proNGF/p75 signaling in bladder function under pathological conditions with a CNS effect overriding the peripheral one.

Concepts: Urinary system, Hypertrophy, Urology, Hyperplasia, Urethra, Urination, Urinary bladder, Urinary incontinence


OBJECTIVE: To develop and test the safety and feasibility of a novel anti-biofilm mechanism configured for wireless capsule endoscopy (WCE) in a sheep bladder model. MATERIALS AND METHODS: A WCE mechanism, designed for long-term bladder monitoring, was developed and introduced into a sheep bladder for 5 months. The transparency of the surface was assessed by evaluating a resolution target placed inside the capsule at serial intervals using cystoscopy under general anaesthesia. Animal behaviour, voiding patterns and urine cultures were monitored throughout the study. At study termination, the capsule was extracted and assessed using scanning electron microscopy. RESULTS: The resolution target was visualized clearly at all investigation points. No notable adverse effects were noted during the entire follow-up period and no urinary tract infection occurred. Scanning electron microscopy confirmed the efficacy of the technology to prevent biofilm formation and surface encrustation. CONCLUSIONS: We report a novel technology that effectively prevents biofilm formation on the outer surface of foreign objects in the urinary tract. Further studies are under way to test the applicability of this technology in bladder WCE to enable high-quality wireless image transmission.

Concepts: Scanning electron microscope, Urinary tract infection, Urinary bladder, Urinary system, Endoscopy, Urethra, Kidney, Urine


PURPOSE: The long-term success rate of dilation and/or internal urethrotomy is low in cases of recurrent urethral stricture disease. This study investigated the Memokath™044TW stent’s ability to maintain urethral patency after dilation or internal urethrotomy of recurrent urethral stricture. MATERIALS AND METHODS: Ninety-two patients with recurrent bulbar urethral strictures (mean length 2.7 cm) were treated with dilation or internal urethrotomy and randomized to short-term urethral catheter diversion (N=29) or insertion of a Memokath™044 stent (N=63). The primary endpoint was urethral patency as assessed by the passage of a calibrated endoscope. Secondary endpoints included urinary symptoms and uroflowmetry parameters. Stents were scheduled to remain in situ 12 months. RESULTS: The rate of successful stent insertion was 93.6% (59/63). The stented patients maintained patency significantly longer than controls (292 days vs. 84 days (median), p<0.001). The patency was reflected in significantly improved uroflowmetry and symptom scores. The stent was removed in 100% of patients. The most frequently noted side-effects in the stented patients were bacteriuria, hematuria, and penile pain - all usually mild and transient. There were no differences in sexual function between the Memokath and control patients. Stent dislocation and occlusion were observed in eight and three patients, respectively. CONCLUSIONS: Patients with recurrent bulbar urethral strictures treated with dilation or urethrotomy and a Memokath™044 stent maintained urethral patency significantly longer than those treated with dilation or urethrotomy alone. The stent's side-effect profile was favorable. The stent was straightforward to insert and was removed without difficulty - even after long-term placement.

Concepts: Insertion, Stent, Time, Medical terms, Urethrotomy, Restenosis, Urethra, Urethral stricture


Strictures of the urethra are the most common cause of obstructed micturition in younger men and frequently recur after initial treatment. Standard treatment comprises internal widening of the strictured area by simple dilatation or by telescope-guided internal cutting (optical urethrotomy), but these interventions are associated with a high failure rate requiring repeated treatment. The alternative option of open urethroplasty whereby the urethral lumen is permanently widened by removal or grafting of the strictured segment is less likely to fail but requires greater expertise. Findings of Improved choice of graft material and shortened hospital stay suggest that urethroplasty may be under utilised. The extent and quality of evidence guiding treatment choice for this condition are uncertain.  

Concepts: Failure rate, Reliability engineering, Cystoscopy, Urination, Failure, Urethrotomy, Urethra, Urethral stricture


We assessed the risk of upper urinary tract obstruction and tumor recurrence following ureteral orifice resection during transurethral resection of bladder tumor.

Concepts: Prostatic stent, Urology, Urethra, Urine, Kidney, Ureter, Urinary system, Urinary bladder


We present a unique case of a large urinary bladder stone protruding through the external urethral meatus in a 77-year-old woman, which was causing acute urinary retention, complicated by bilateral hydronephrosis, and was removed under topical anesthesia in the emergency department. Epidemiology, etiology, clinical presentation and management of urinary bladder stones are briefly discussed.

Concepts: Urine, Kidney, Urinary meatus, Urology, Urinary retention, Urethra, Urinary system, Urinary bladder