Formation and characteristics of laminar vortices in microscale environments within an obstructed and stented ureter: A computational study

Despite the widespread clinical usage of ureteric stents for the drainage of urine in impaired ureters (e.g. caused by ureteric stones, tumors) many complications are still associated with stent's implants. Encrusting and infective events, due to crystals' deposition and bacterial adhesion on the stent surface, usually lead to stent failure. In earlier experimental results we showed the presence of vortices in regions of the stent (e.g. side holes) which are thought to act as initial anchoring sites for encrusting deposits. In the current study we show computationally how the stent's design is a crucial factor for developing the vortices

Selective reduction of neurotransmitter release by cAMP-dependent pathways in mouse detrusor

Parasympathetic nerve-mediated contractions of detrusor smooth muscle are generated by ATP and acetylcholine (ACh) release from efferent nerve terminals. In humans, ACh is responsible for detrusor contractions in normal human bladders, whereas ATP has an additional role in overactive bladder pathologies. The ATP metabolite, adenosine, relaxes nerve-mediated contractions, with a potential action via presynaptic adenosine A1 receptor activation and subsequent suppression of neuronal ATP release. We investigated the effect of A1 receptor activation and downstream cAMP-dependent pathways on nerve-mediated ATP and ACh release, and detrusor contraction in mouse detrusor. Bladders from male C57BL/6 mice (12 wk) were used for in vitro experiments. Upon electrical field stimulation of intact preparations (detrusor and mucosal layers), ATP or ACh release was measured simultaneously with tension recordings. Activation of A1 receptors by adenosine or exogenous agonists reduced the lower frequency component of nerve-mediated contractions and neuronal ATP release. The A1 receptor antagonist abolished these effects. A1 receptor activation inhibits adenylyl cyclase (AC) activity and cAMP generation. The effect of A1 receptor activation was mimicked by a PKA antagonist but not by modulators of exchange proteins activated by cAMP, demonstrating that modulation of nerve-mediated ATP release is via PKA. Adenosine had no effect on ACh release or the higher frequency component of nerve-mediated contractions. Differential regulation of neurotransmitter release is possible at the detrusor nerve-muscle junction, as demonstrated by A1 receptor activation, and downstream inhibition of AC, cAMP generation, and PKA. The ability to specifically attenuate ATP release offers a potential to target purinergic motor pathways enhanced in overactive bladder pathologies

An Exploration of the Control of Micturition Using a Novel in Situ Arterially Perfused Rat Preparation

Our goal was to develop and refine a decerebrate arterially perfused rat (DAPR) preparation that allows the complete bladder filling and voiding cycle to be investigated without some of the restrictions inherent with in vivo experimentation [e.g., ease and speed of set up (30 min), control over the extracellular milieu and free of anesthetic agents]. Both spontaneous (naturalistic bladder filling from ureters) and evoked (in response to intravesical infusion) voids were routinely and reproducibly observed which had similar pressure characteristics. The DAPR allows the simultaneous measurement of bladder intra-luminal pressure, external urinary sphincter–electromyogram (EUS–EMG), pelvic afferent nerve activity, pudendal motor activity, and permits excellent visualization of the entire lower urinary tract, during typical rat filling and voiding responses. The voiding responses were modulated or eliminated by interventions at a number of levels including at the afferent terminal fields (intravesical capsaicin sensitization–desensitization), autonomic (ganglion blockade with hexamethonium), and somatic motor (vecuronium block of the EUS) outflow and required intact brainstem/hindbrain-spinal coordination (as demonstrated by sequential hindbrain transections). Both innocuous (e.g., perineal stimulation) and nociceptive (tail/paw pinch) somatic stimuli elicited an increase in EUS–EMG indicating intact sensory feedback loops. Spontaneous non-micturition contractions were observed between fluid infusions at a frequency and amplitude of 1.4 ± 0.9 per minute and 1.4 ± 0.3 mmHg, respectively and their amplitude increased when autonomic control was compromised. In conclusion, the DAPR is a tractable and useful model for the study of neural bladder control showing intact afferent signaling, spinal and hindbrain co-ordination and efferent control over the lower urinary tract end organs and can be extended to study bladder pathologies and trial novel treatments

Understanding the Impact of Urinary Incontinence in Persons with Dementia:Development of an Interdisciplinary Service Model

Introduction. Prevalence of urinary symptoms such as incontinence (UI) in patients with dementia is estimated to exceed 50%. The resultant psychological and socio-economic burden can be substantial. Our aim was to develop a dedicated urology service within a cognitive impairment clinic in order to treat and better understand the bothersome urinary symptoms suffered by persons with dementia. Methods. Patients attending this clinic were invited to be assessed and interviewed by urologist, together with their family and/or carer. In addition, formal history, examination and relevant investigations, themes of importance such as quality of life, and select question items were drawn from validated questionnaires. Multidisciplinary team (MDT) meeting was carried out on the same day. Outcomes of the first 75 patients with UI and dementia have been reported. Results. Average age was 70 years (range 58–98). Majority of persons had a diagnosis of Alzheimer’s disease (n = 43, 57%). Average score for how much urine leakage interferes with everyday life was 7.7/10 (range 2–10). 58.7% (n = 44) revealed some degree of sleep disturbance due to UI. 83% (n = 62) stated daily activities were limited due to UI. Two-thirds of persons with dementia (n = 50) stated their bladder problem makes them feel anxious. 88% (n = 67) felt the topic was socially embarrassing. All carers stated that the person’s continence issues affect the care they provide. Less than one-third of carers (30.7%, n = 23) were aware of or had been in contact with any bladder and bowel community service. More than half of the carers (n = 46, 65%) were concerned incontinence may be a principal reason for future nursing home admission. Conclusion. UI can be distressing for persons with dementia. Care partners were concerned about loss of independence and early nursing home admission. Awareness of bladder and bowel services should be increased