Functional analysis of natriuretic peptide receptors in the bladder of the toad, bufo marinus

This study aimed to localize and characterize natriuretic peptide binding sites in the urinary bladder of Bufo marinus and to then examine the effect of natriuretic peptides on the bladder vascular tone and water reabsorption in isolated perfused bladder preparations. Specific ¹²⁵I-rat atrial natriuretic peptide (¹²⁵I-rANP) binding sites were present on blood vessels, muscle, and epithelium. In tissue sections and/or isolated membranes, the binding was completely displaced by frog ANP, rat ANP, and porcine C-type natriuretic peptide (CNP; membranes only). However, a reduction in binding was observed after incubation with ¹²⁵I-rANP and 1 μM of the natriuretic peptide receptor-C (NPR-C) ligand C-ANF, but residual binding remained suggesting the presence of two distinct binding sites. Electrophoresis of bladder membranes cross-linked to ¹²⁵I-rANP identified two bands at approximately 70 and 140 kDa that correspond to the monomeric mass of NPR-C and the guanylate cyclase receptors, respectively. Furthermore, the presence of natriuretic peptide receptor-A and NPR-C mRNA in the bladder was demonstrated with reverse transcription–polymerase chain reaction. In addition, rat ANP, frog ANP, and porcine CNP stimulated a significant increase in cGMP generation in bladder membrane preparations, which indicated the presence of guanylate cyclase-linked receptors. In perfused bladder preparations, arginine vasotocin increased perfusion pressure and water permeability. The infusion of frog ANP or porcine CNP failed to alter perfusion pressure or water reabsorption in the presence or absence of arginine vasotocin. This study identified a well-developed natriuretic peptide receptor system in the urinary bladder of B. marinus but the function of the receptors remains unclear.

Upregulated MT1-MMP/TIMP-2 axis in the TSU-Pr1-B1/B2 model of metastatic progression in transitional cell carcinoma of the bladder

Muscle invasive transitional cell carcinoma (TCC) of the bladder is associated with a high frequency of metastasis, resulting in poor prognosis for patients presenting with this disease. Models that capture and demonstrate step-wise enhancement of elements of the human metastatic cascade on a similar genetic background are useful research tools. We have utilized the transitional cell carcinoma cell line TSU-Pr1 to develop an in vivo experimental model of bladder TCC metastasis. TSU-Pr1 cells were inoculated into the left cardiac ventricle of SCID mice and the development of bone metastases was monitored using high resolution X-ray. Tumor tissue from a single bone lesion was excised and cultured in vitro to generate the TSU-Pr1-B1 subline. This cycle was repeated with the TSU-Pr1-B1 cells to generate the successive subline TSU-Pr1-B2. DNA profiling and karyotype analysis confirmed the genetic relationship of these three cell lines. In vitro, the growth rate of these cell lines was not significantly different. However, following intracardiac inoculation TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2 exhibited increasing metastatic potential with a concomitant decrease in time to the onset of radiologically detectable metastatic bone lesions. Significant elevations in the levels of mRNA expression of the matrix metalloproteases (MMPs) membrane type 1-MMP (MT1-MMP), MT2-MMP and MMP-9, and their inhibitor, tissue inhibitor of metalloprotease-2 (TIMP-2), across the progressively metastatic cell lines, were detected by quantitative PCR. Given the role of MT1-MMP and TIMP-2 in MMP-2 activation, and the upregulation of MMP-9, these data suggest an important role for matrix remodeling, particularly basement membrane, in this progression. The TSU-Pr1-B1/B2 model holds promise for further identification of important molecules.

Natriuretic peptide regulation of the kidney and urinary bladder in the cane toad, Bufo marinus

The natriuretic peptide system of mammals is important in the control of blood volume but its function in non-mammalian animals is unclear. This study identified a functional natriuretic peptide system in an amphibian and showed that the hormones are involved in the control of fluid balance.

Incidence of bladder cancer in Sri Lanka : analysis of the cancer registry data and review of the incidence of bladder cancer in the South Asian population

PurposeTo investigate the incidence of bladder cancer (BC) in Sri Lanka and to compare risk factors and outcomes with those of other South Asian nations and South Asian migrants to the United Kingdom (UK) and the United States (US).Materials and MethodsThe incidence of BC in Sri Lanka was examined by using two separate cancer registry databases over a 5-year period. Smoking rates were compiled by using a population-based survey from 2001 to 2009 and the relative risk was calculated by using published data.ResultsA total of 637 new cases of BC were diagnosed over the 5-year period. Sri Lankan BC incidence increased from 1985 but remained low (1.36 and 0.3 per 100,000 in males and females) and was similar to the incidence in other South Asian countries. The incidence was lower, however, than in migrant populations in the US and the UK. In densely populated districts of Sri Lanka, these rates almost doubled. Urothelial carcinoma accounted for 72%. The prevalence of male smokers in Sri Lanka was 39%, whereas Pakistan had higher smoking rates with a 6-fold increase in BC.ConclusionsSri Lankan BC incidence was low, similar to other South Asian countries (apart from Pakistan), but the actual incidence is likely higher than the cancer registry rates. Smoking is likely to be the main risk factor for BC. Possible under-reporting in rural areas could account for the low rates of BC in Sri Lanka. Any genetic or environmental protective effects of BC in South Asians seem to be lost on migration to the UK or the US and with higher levels of smoking, as seen in Pakistan.

Does successful treatment of constipation or faecal impaction resolve lower urinary tract symptoms? A structured review of the literature

Consensus guidelines advocate the treatment of constipation and faecal impaction in order to improve symptoms of urinary frequency, urgency and urinary incontinence and to promote bladder emptying in the absence of urinary tract obstruction. This structured review of the literature was undertaken to search for and appraise evidence to support or negate the hypothesis of this relationship. The search strategy was comprehensive and identified six relevant studies. Two of these had been conducted on an adult population and four studies involved children with constipation. These studies were appraised for methodological quality. It was found that sample sizes were small and evidence was inconsistent. Variable methods of reporting meant that data were not able to be pooled for meta-analysis.
Based on the limited and conflicting evidence, it is recommended that further research be undertaken to identify any correlation between bowel and bladder function.

The challenge of managing continence care in residential aged care settings : recommendations for research and practice

Incontinence-related problems are a major reason for placement in residential aged care facilities. Data from the Residential Classification Scale indicates that 86% of people in residential aged care facilities in Australia are dependent on others for bladder management, 77% require some support with bowel management and 78% require some support with toileting. In this paper, we present an overview of the literature on the issues that need to be considered for the management of incontinence in residential aged care settings. Based on this literature, we make recommendations for research and practice. Although residential care facilities are mandated to provide continence care, there is little research evidence on which to base care or to evaluate the effectiveness of current practices. Further research is required to address this gap in information to ensure delivery of residential aged care that meets the requirements of the Aged Care Act 1997.

Does a continence educational brochure promote health-seeking behavior?

OBJECTIVE: This study reviewed whether participants who were given a continence education package, which included a Continence Educational Brochure (CEB), and who indicated that they were bothered by incontinence symptoms changed health-seeking behaviors about their incontinence problem because of being given the brochure.
METHOD: This study used a descriptive and exploratory design. Participants were given the CEB and asked to read the information. They were also asked to complete a continence questionnaire and mail this back to the research team. Participants who indicated that they were bothered by a continence problem and consented to being interviewed were telephoned 2 to 3 months later. They were asked questions to determine their actions and progress in relation to managing their continence problem and whether the CEB had influenced their behavior.
SETTING AND SUBJECT: A total of 631 participants (352 females, 55.8%; 279 males, 44.2%) from 4 rural and regional settings in Victoria, Australia, participated. Of this sample, 111 participants (78 females, 70.3%; 33 males, 29.7%) who reported that they were bothered by a continence problem were interviewed 3 months after being given the CEB.
RESULTS: Two thirds of the total sample of participants (n = 111) sought help for their continence problem. Approximately 70.3% (n = 78) continued to have a continence problem. Of this group, 84.6% were still bothered by the continence problem and 65.4% had taken action to treat their incontinence. Forty-nine participants (44.1%) indicated that they had discussed the issue of bladder or bowel problems with someone directly because of this study or the information contained in the brochure. More than 94% of participants who remembered the CEB indicated that they believed the brochure would be helpful if given to other people.
CONCLUSIONS: These findings suggest that the CEB prompted individuals to discuss their continence problem and in fewer cases to seek professional help. Given these findings, distribution of a continence education package is advocated as a continence health promotion strategy.

A perspective on the role of natriuretic peptides in amphibian osmoregulation

The natriuretic peptide (NP) system is a complex family of peptides and receptors that is primarily linked to the maintenance of osmotic and cardiovascular homeostasis. In amphibians, the potential role(s) of NPs is complicated by the range of osmoregulatory strategies found in amphibians, and the different tissues that participate in osmoregulation. Atrial NP, brain NP, and C-type NP have been isolated or cloned from a number of species, which has enabled physiological studies to be performed with homologous peptides. In addition, three types of NP receptors have been cloned and partially characterised. Natriuretic peptides are always potent vasodilators in amphibian blood vessels, and ANP has been shown to increase the permeability of the microcirculation. In the perfused kidney, ANP causes vasodilation, diuresis and natriuresis that are caused by an increased GFR rather than effects in the renal tubules. These data are supported by the presence of ANP receptors only on the glomeruli and renal blood vessels. In the bladder and skin, the function of NPs is enigmatic because physiological analysis of the effects of ANP on bladder and skin function has yielded conflicting data with no clear role for NPs being revealed. Overall, NPs often have no direct effect, but in some studies they have been shown to inhibit the function of AVT. In addition, there is evidence that ANP can inhibit salt retention in amphibians since it can inhibit the ability of adrenocorticotrophic hormone or angiotensin II to stimulate corticosteroid secretion. It is proposed that an important role for cardiac NPs could be in the control of hypervolaemia during periods of rapid rehydration, which occurs in terrestrial amphibians.

Habit retraining for the management of urinary incontinence in adults (review)

Background
Habit retraining is toileting assistance given by a caregiver to adults with urinary incontinence. It involves the identification of an incontinent person's natural voiding pattern and the development of an individualised toileting schedule which pre-empts involuntary bladder emptying.

Objectives
To assess the effects of habit retraining for the management of urinary incontinence in adults.

Search strategy
We searched the Cochrane Incontinence Group specialised register (9 May 2002), MEDLINE (January 1966 to February 2004), EMBASE (January 1980 to Week 18-2002), CINAHL (January 1982 to February 2001), PsychINFO (January 1972 to August 2002), Biological Abstracts (January 1980 to December 2000), Current Contents (January 1993 to December 2001) and the reference lists of relevant articles. We also contacted experts in the field, searched relevant websites and hand searched journals and conference
proceedings.

Selection criteria
All randomised or quasi-randomised controlled trials comparing habit retraining delivered either alone or in conjunction with another intervention for urinary incontinence in adults.

Data collection and analysis
Data extraction and quality assessment were undertaken by at least two people working independendy of each other. Any differences were resolved by discussion. The relative risks for dichotomous data were calculated with 95% confidence intervals. Where data were insufficient for a quantitative analysis, a narrative overview was undertaken.

Main results
Three trials with a total of 337 participants met the inclusion criteria, describing habit retraining combined with other approaches compared with usual care. Participants were primarily care-dependent elderly women with concurrent cognitive and/or physical impairment, residing in either a residential aged-care facility or in their own home. Outcomes included incidence and/or severity of urinary incontinence, the prevalences of urinary tract infection, skin rash and skin breakdown, cost and caregiver preparedness, role strain and burden. Caregivers found it difficult to maintain voiding records and to implement the toileting program. A 61% compliance rate was reported in one trial .

There were no statistically significant differences in the incidence and in the volume of incontinence between groups. Within group analyses did however show improvements on these measures. Reductions were also reported for the intervention group in one study for skin rash, skin breakdown and in caregivers' perceptions of their level of stress. Descriptive data on the. intervention suggests that habit retraining is a labour-intense activity. Electronic loggers, used as an adjunct to caregiver-delivered wet/dry checks, were reported as providing more accurate data than that from caregiver conducted wet/dry checks. To date, no analysis of the time and resources associated with these comparisons is available.

Reviewers' conclusions
Data on habit retraining are few and of insufficient quality to provide a firm basis for practice.

Peripartum urinary incontinence : a study of midwive's knowledge and practices

Urinary incontinence impacts on women's quality of life and their wellbeing. The objectives of this study were to obtain knowledge and information on midwives’ assessment and management practices of urinary incontinence in childbearing women and to explore midwives’ knowledge of risk factors associated with developing urinary incontinence. A non-experimental descriptive research design was used, and participants were current members of the Victorian branch of the Australian College of Midwives. Data was obtained using a survey tool that contained both qualitative and quantitative questions. Key findings indicated that the majority of midwives do not assess women for urinary incontinence during the peripartum period and guidelines for bladder management in maternity services were lacking.

Continence prevalence and management in an acute hospital

Learning Objective 1: describe the prevalence of incontinence within an Australian acute care hospital

Learning Objective 2: describe the current management practices for incontinence with regard to patients in an acute care hospital
Introduction: In 1998 the World Health Organisation recognised the international problem of incontinence. However, incontinence remains a major problem that affects more than 3.8 million Australians. Currently, there are no Australian guidelines governing the management of continence within the acute healthcare setting. Cabrini Health sought to identify the prevalence of incontinence in the acute inpatient setting and pilot a Continence Management Program to improve patient safety and patient outcomes.

Aim: The aim of this study was to determine the prevalence of and current management practices for incontinence with regard to Cabrini Health inpatients.

Method: The sample comprised 392 inpatients across three campuses of Cabrini Health (mean age= 68.3 years). Continence prevalence was assessed using a validated Continence Point Prevalence Tool.

Results: Urinary incontinence prevalence was 14%. The resulting overall faecal incontinence prevalence was 7.4%. There were 113 (52.3%) patients who were not incontinent and were using a continence product/device. Fifteen (25.9%) patients were incontinent and were not using any form of continence product/device. There were 43 (74.1%) patients who were incontinent and were using a continence product/device. For the large majority of patients, the admission notes contained documentation of their bladder and bowel function. Specifically, 46 (11.8%) patients had no form of admission documentation relating to bowel function and 45 (11.5%) patients had no form of admission documentation regarding to bladder function.

Conclusions: This study provided baseline continence prevalence for Cabrini Health. There is a need for evidence-based guidelines to support the management of incontinent patients. These interventions will assist staff to educate patients on appropriate choice of continence products and enable patients to maintain or regain continence. Thereby, leading to improved outcomes for patients and improved risk management.

Studies of the human lymphocyte P2Z receptor and its activation of phospholipase D

Extracellular adenosine 5′-triphosphate (ATP) is an agonist for the P2Z receptor of human leukaemic lymphocytes and opens a Ca ²⁺-selective ion channel, which also conducts Ba²⁺, Sr²⁺ and the small fluorescent dye, ethidium⁺. A wide range of receptor agonists, many of which raise cytosolic [Ca²⁺] activate phospholipase D (PLD). In the present study, it was shown that both ATP and 3′-O-(4-benzoylbenzoyl)-ATP (BzATP) stimulated PLD activity in a concentration-dependent manner, and the inhibitory effects of suramin, oxidised ATP, extracellular Na⁺ and Mg²⁺ suggested that the effect of these agonists is mediated by P2Z receptors. The role of divalent cations in ATP-stimulated PLD activity was investigated. Several agonists (eg ATP, thapsigargin, ionomycin) stimulated a rise in cytosolic [Ca²⁺] in human lymphocytes, but only ATP and ionomycin stimulated PLD activity. When Ca²⁺ influx was prevented by EGTA, the majority of ATP-stimulated and all of ionomycin-stimulated PLD activity was inhibited. Preloading cells with the Ca²⁺ chelator, BAPTA, reduced cytosolic [Ca²⁺] and, paradoxically, ATP-stimulated PLD activity was potentiated. ATP-stimulated PLD activity was supported by both Ba²⁺ and Sr²⁺ when they were substituted for extracellular Ca²⁺. Furthermore, both ATP-stimulated PLD activity and ATP-stimulated ¹³³Ba²⁺ influx showed a linear dependence on extracellular [Ba²⁺]. Thus it was concluded that ATP stimulated PLD activity in direct proportion to the influx of divalent cations through the P2Z ion channel and this PLD activity was insensitive to changes in bulk cytosolic [Ca²⁺]. The calmodulin (Ca²⁺/CaM) inhibitor, trifluoperazine (TFP) inhibited ionomycin- and ATP-stimulated PLD activity and ATP-stimulated apoptosis, but had no effect on PLD activity already activated by ATP. However, TFP inhibited ATP-stimulated Ca²⁺, Ba²⁺ and ethidium⁺ fluxes, at concentrations below those which inhibit Ca²⁺/CaM, suggesting that TFP inhibits the P2Z receptor. Similarly, the isoquinolinesulphonamide, KN-62, a selective inhibitor of Ca²⁺/CaM-dependent protein kinase II (CaMKII), also prevented ATP-stimulated apoptosis, but had no effect on pre-activated PLD. In addition, KN-62, and an analogue, KN-04, which has no effect on CaMKII, potently inhibited ATP-stimulated Ba²⁺ influx (IC₅₀ 12.7 ± 1.5 and 17.3 ± 2.7 nM, respectively), ATP-stimulated ethidium⁺ uptake (IC₅₀ 13.1 ± 2.6 and 37.2 ± 8.9 nM, respectively), ATP-stimulated phospholipase D activity (50% inhibition 5.9 ± 1.2 and 9.7 ± 2.8 nM, respectively) and ATP-induced shedding of the surface adhesion molecule, L-selectin (IC₅₀ 31.5 ± 4.5 and 78.7 ± 10.8 nM, respectively). They did not inhibit phorbol ester- or ionomycin-stimulated PLD activity or phorbol ester-induced L-selectin shedding. Neither KN-62 nor KN-04 (both 500 nM) have any effect on UTP-stimulated Ca²⁺ transients in fura-2-loaded human neutrophils, a response which is mediated by the P2Y₂ receptor, neither did they inhibit ATP-stimulated contractile responses mediated by the P2X₁ receptor of guinea pig urinary bladder. Thus, KN-62 and KN-04 are almost equipotent as P2Z inhibitors with IC₅₀s in the nanomolar, indicating that their actions cannot be due to CaMKII inhibition, but rather that they are potent and direct inhibitors of the P2Z receptor. Extracellular ATP-induced shedding of L-selectin from lymphocytes into the medium is a Ca²⁺-independent response. L-selectin is either cleaved by a metalloproteinase or a PLD with specificity for glycosylphosphatidylinositol (GPI). The novel hydroxamic acid-based zinc chelator, Ro-31-9790 blocks ATP-induced L-selectin shedding, but was without effect on ATP-induced Ba²⁺ influx or ATP-stimulated PLD activity. Furthermore, another zinc chelator, 1,10-phenanthroline, an inhibitor of a GPI-PLD, potentiated rather than inhibited ATP-stimulated PLD activity, suggesting that ATP-induced L-selectin shedding and ATP-stimulated PLD activity are independent of each other. Although extracellular ATP is the natural ligand for the lymphocyte P2Z receptor, it is less potent than BzATP in stimulating Ba²⁺ influx. Concentration-response curves for BzATP- and ATP-stimulated ethidium⁺ influx gave EC₅₀s 15.4 ± 1.4 µM and 85.6 ± 8.8 µM, respectively. The maximal response to ATP was only 69.8 ± 1.9% of that for BzATP. Hill coefficients were 3.17 ± 0.24 and 2.09 ± 0.45 for BzATP and ATP respectively, suggesting greater positive cooperativity for BzATP than for ATP in opening the P2Z-operated ion channel. A rank order of agonist potency of BzATP > ATP = 2MeSATP > ATPγS was observed for agonist-stimulated ethidium⁺ influx, while maximal influxes followed a rank order of BzATP > ATP > 2MeSATP > ATPγS. When ATP (300 -1000 µM) was added simultaneously with 30 µM BzATP (EC₉₀), it reduced both ethidium⁺ and Ba²⁺ fluxes by 30 - 40% relative to values observed with BzATP alone. KN-62, previously shown to be a specific inhibitor of the lymphocyte P2Z receptor, was a less potent antagonist of BzATP-induced fluxes than ATP, when maximal concentrations of both agonists (50 and 500 µM respectively) were used. However, when BzATP (18 µM) was used at a concentration equiactive with a maximally effective ATP concentration, KN-62 showed the same inhibitory potency for both agonists. The ecto-ATPase antagonist, ARL-67156, inhibited both ATP- and BzATP-stimulated Ba²⁺ influx, suggesting that the lower efficacy of ATP compared with BzATP was not due to preferential hydrolysis of ATP. Thus, the natural ligand, ATP, is a partial agonist for the P2Z receptor while BzATP is a full agonist. Moreover the competitive studies show that only a single class of P2-receptor (P2Z class) is expressed on human leukaemic lymphocytes. Both ATP- and BzATP-stimulated PLD activity were significantly inhibited (P < 0.05) when cells were suspended in iso-osmotic choline Cl medium. Choline⁺ was found to be a permeant for the P2Z ion channel, since ATP induced a large uptake of [¹⁴C]choline⁺ (60 to 150 µmol/ml intracellular water) during a 5 min incubation, which remained in the cells for several hours, and ATP was used to load cells with these levels of choline⁺. Intracellular choline⁺ inhibited ATP-, BzATP-, PMA- and ionomycin-stimulated PLD activity. Brief exposure of lymphocytes to ATP increased the subsequent basal rate of ethidium⁺ uptake, and this was prevented by intracellular choline⁺. It is proposed that P2Z-mediated Ca²⁺ influx in lymphocytes activates PLD leading to significantly changes of the phospholipid composition of the plasma membrane, which subsequently produces a permeability lesion, which in turn contributes to cell death.