The urothelium is a multifunctional tissue that not only acts as a barrier between the vesical contents of the lower urinary tract and the underlying tissues but also acts as a sensory organ by transducing physical and chemical stresses to the attendant afferent nervous system and underlying smooth muscle. This review will consider the nature of the stresses that the urothelium can transduce; the transmitters that mediate the transduction process; and how lower urinary pathologies, including overactive bladder syndrome, painful bladder syndrome and bacterial infections, are associated with alterations to this sensory system. In particular, the role of muscarinic receptors and the TRPV channels system will be discussed in this context. The urothelium also influences the contractile state of detrusor smooth muscle, both through modifying its contractility and the extent of spontaneous activity; potential pathways are discussed. The potential role that the urothelium may play in bladder underactivity is introduced, as well as potential biomarkers for the condition that may cross the urothelium to the urine. Finally consideration is given to vesical administration of therapeutic agents that influence urinary tract function and how the properties of the urothelium may determine the effectiveness of this mode of delivery.
Characterizing the integrative physiology of the bladder requires whole organ preparations. The purpose of this study was to validate an isolated large animal (pig) bladder preparation, through arterial and intravesical drug administration, intravesical pressure recording, and filming of surface micromotions. Female pig bladders were obtained from the local abattoir and arterially perfused in vitro. Arterial and intravesical pressures were recorded at varying volumes. Bladder viability was assessed histologically and by monitoring inflow and outflow pH. Arterial drug administration employed boluses introduced into the perfusate. Intravesical administration involved slow instillation and a prolonged dwell-time. Surface micromotions were recorded by filming the separation of surface markers concurrently with intravesical pressure measurement. Adequate perfusion to all bladder layers was achieved for up to 8 h; there was no structural deterioration nor alteration in inflow and effluent perfusate pH. Arterial drug administration (carbachol and potassium chloride) showed consistent dose-dependent responses. Localized movements (micromotions) occurred over the bladder surface, with variable correlation with fluctuations of intravesical pressure. The isolated pig bladder is a valid approach to study integrative bladder physiology. It remains viable when perfused in vitro, responds to different routes of drug administration and provides a model to correlate movements of the bladder wall directly to variation of intravesical pressure.
Overactive bladder syndrome (OAB) is a symptom-based diagnosis characterised by the presence of urinary urgency. It is highly prevalent and overlaps with the presence of bladder contractions during urine storage, which characterises the urodynamic diagnosis of detrusor overactivity. Animal models are needed to understand the pathophysiology of OAB, but the subjective nature of the symptom complex means that interpretation of the findings in animals requires caution. Because urinary urgency cannot be ascertained in animals, surrogate markers such as frequency, altered toileting areas, and non-micturition contractions have to be used instead. No model can recapitulate the subjective, objective, and related factors seen in the clinical setting. Models used include partial bladder outlet obstruction, the spontaneous hypertensive rat, the hyperlipidaemic rat, various neurological insults and some gene knock-outs. Strengths and weaknesses of these models are discussed in the context of the inherent difficulties of extrapolating subjective symptoms in animals.
Based on the think tank discussion, the ICI-RS panel put forward the following recommendations: the need to acquire normative age-matched data in women to define "normal" and "pathological" values of urodynamic parameters; the inclusion of additional clinical data in new nomograms and the use of this extra dimension to develop clinically applicable nomograms for female BOO and contractility; and finally, the need to take into account the variability of BOO in women when developing female bladder contractility nomograms.
Older patients can successfully be taught ISC in a high proportion, and it can be offered as an alternative to an indwelling catheter irrespective of age.
BACKGROUND There is concern across all medical specialties that shift patterns and reduced working hours are detrimental to training, and that craft specialties have been most affected. This study aimed to examine the effects of these changes to training on the quantity of operating performed by surgical trainees in a UK teaching hospital. METHODS This retrospective study of prospectively collected computerised theatre data examined elective and emergency general surgical operations performed over four time periods: 1996 (Calman), 2001 (New Deal), 2004 and 2009 (European Working Time Directive). Procedures were analysed according to grade of surgeon and time of day. RESULTS In 1996, most appendicectomies (72.2%) were performed by senior house officers (SHOs), compared with 3.8% in 2009. By 2009, SHOs did not perform any emergency procedures other than abscess drainage and appendicectomy. The proportion of emergency operating performed by specialist registrar (SpRs) has remained constant, but elective operating has reduced from 34.6% (1996) to 15.7% (2009). Supervision of both SHOs and SpRs has increased between 1996 and 2009 in both elective and emergency work. CONCLUSIONS The proportion of operating performed by SpRs and SHOs has fallen over the last decade, coinciding with implementation of structural changes to training, the advent of minimally invasive techniques, and the drive for a consultant led health service. Trainees may therefore require increased supervision as well as protected theatre sessions to balance operative training with ward based duties. Education must be integrated into working practice in order for trainees to achieve expected competencies and ultimately produce adequately experienced consultants.
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