Modulation of fast sodium current in airway smooth muscle cells by exchange protein directly activated by cAMP

Airway smooth muscle (ASM) cells from mouse bronchus express a fast sodium current mediated by NaV1.7. We present evidence that this current is regulated by cAMP. ASM cells were isolated by enzymatic dispersal and studied using the whole cell patch clamp technique at room temperature. A fast sodium current, INa, was observed on holding cells under voltage clamp at -100 mV and stepping to -20 mV. This current was reduced in a concentration-dependent manner by denopamine (10 and 30 µM), a β-adrenergic agonist. Forskolin (1 µM), an activator of adenylate cyclase, reduced the current by 35%, but 6-MB-cAMP (300 µM), an activator of protein kinase A (PKA), had no effect. In contrast, 8-pCPT-2-O-Me-cAMP-AM (007-AM, 10 µM), an activator of exchange protein directly activated by cAMP (Epac), reduced the current by 48%. The inhibitory effect of 007-AM was still observed in the presence of dantrolene (10 µM), an inhibitor of ryanodine receptors, and when cytosolic [Ca2+] was buffered by inclusion of 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, Sigma (BAPTA) (50 µM) in the pipette solution, suggesting that the inhibition of INa was not due to Ca2+-release from intracellular stores. When 007-AM was tested on the current-voltage relationship, it reduced the current at potentials from -30 to 0 mV, but had no effect on the steady-state activation curve. However, the steady-state inactivation V1/2, the voltage causing inactivation of 50% of the current, was shifted in the negative direction from -76.6 mV to -89.7 mV. These findings suggest that cAMP regulates INa in mouse ASM via Epac, but not PKA.NEW & NOTEWORTHY β-adrenergic agonists are commonly used in inhalers to treat asthma and chronic obstructive pulmonary disease. These work by causing bronchodilation and reducing inflammation. The present study provides evidence that these drugs have an additional action, namely, to reduce sodium influx into airway smooth muscle cells via fast voltage-dependent channels. This may have the dual effect of promoting bronchodilation and reducing remodeling of the airways, which has a detrimental effect in these diseases.

In silico interrogation of the miRNAome of infected hematopoietic cells to predict processes important for human cytomegalovirus latent infection

Human cytomegalovirus (HCMV) latency in CD34+ progenitor cells is the outcome of a complex and continued interaction of virus and host that is initiated during very early stages of infection and reflects pro- and anti-viral activity. We hypothesized that a key event during early infection could involve changes to host miRNAs, allowing for rapid modulation of the host proteome. Here, we identify 72 significantly upregulated miRNAs and three that were downregulated by 6hpi of infection of CD34+ cells which were then subject to multiple in silico analyses to identify potential genes and pathways important for viral infection. The analyses focused on the upregulated miRNAs and were used to predict potential gene hubs or common mRNA targets of multiple miRNAs. Constitutive deletion of one target, the transcriptional regulator JDP2, resulted in a defect in latent infection of myeloid cells; interestingly, transient knockdown in differentiated dendritic cells resulted in increased viral lytic IE gene expression, arguing for subtle differences in the role of JDP2 during latency establishment and reactivation of HCMV. Finally, in silico predictions identified clusters of genes with related functions (such as calcium signaling, ubiquitination, and chromatin modification), suggesting potential importance in latency and reactivation. Consistent with this hypothesis, we demonstrate that viral IE gene expression is sensitive to calcium channel inhibition in reactivating dendritic cells. In conclusion, we demonstrate HCMV alters the miRNAome rapidly upon infection and that in silico interrogation of these changes reveals new insight into mechanisms controlling viral gene expression during HCMV latency and, intriguingly, reactivation.

Excitatory cholinergic responses in mouse primary bronchial smooth muscle require both Ca2+ entry via l-type Ca2+ channels and store operated Ca2+ entry via Orai channels

Malfunctions in airway smooth muscle Ca²⁺-signalling leads to airway hyperresponsiveness in asthma and chronic obstructive pulmonary disease. Ca²⁺-release from intracellular stores is important in mediating agonist-induced contractions, but the role of influx via l-type Ca²⁺ channels is controversial. We re-examined roles of the sarcoplasmic reticulum Ca²⁺ store, refilling of this store via store-operated Ca²⁺ entry (SOCE) and l-type Ca²⁺ channel pathways on carbachol (CCh, 0.1-10 µM)-induced contractions of mouse bronchial rings and intracellular Ca²⁺ signals of mouse bronchial myocytes. In tension experiments, the ryanodine receptor (RyR) blocker dantrolene (100 µM) reduced CCh-responses at all concentrations, with greater effects on sustained rather than initial components of contraction. 2-Aminoethoxydiphenyl borate (2-APB, 100 μM), in the presence of dantrolene, abolished CCh-responses, suggesting the sarcoplasmic reticulum Ca²⁺ store is essential for contraction. The SOCE blocker GSK-7975A (10 µM) reduced CCh-contractions, with greater effects at higher (e.g. 3 and 10 µM) CCh concentrations. Nifedipine (1 µM), abolished remaining contractions in GSK-7975A (10 µM). A similar pattern was observed on intracellular Ca²⁺-responses to 0.3 µM CCh, where GSK-7975A (10 µM) substantially reduced Ca²⁺ transients induced by CCh, and nifedipine (1 µM) abolished remaining responses. When nifedipine (1 µM) was applied alone it had less effect, reducing tension responses at all CCh concentrations by 25% - 50%, with greater effects at lower (e.g. 0.1 and 0.3 µM) CCh concentrations. When nifedipine (1 µM) was examined on the intracellular Ca²⁺-response to 0.3 µM CCh, it only modestly reduced Ca²⁺ signals, while GSK-7975A (10 µM) abolished remaining responses. In conclusion, Ca²⁺-influx from both SOCE and l-type Ca²⁺ channels contribute to excitatory cholinergic responses in mouse bronchi. The contribution of l-type Ca²⁺ channels was especially pronounced at lower doses of CCh, or when SOCE was blocked. This suggests l-type Ca²⁺ channels might be a potential target for bronchoconstriction under certain circumstances.

318 CARER STRESS REVIEW IN COMPLEX CASES REQUIRING INTERVENTION BY A COMMUNITY-BASED OLDER PERSONS TEAM

Background

Complex cases of older adults suffering from multimorbidity are continuing to increase in number. The integrated care team, overseen by a consultant geriatrician, aims to facilitate the management of stable complex cases in the community. Patient care is largely affected by their support system at home; therefore, it is of great importance to ensure that the patient’s primary carer is receiving the support they require to facilitate the older patients’ management in the community. Our aim is to assess carer stress levels before and after Multi-Disciplinary Team (MDT) integrated care intervention.

Methods

Study Population were carers of patients identified as complex cases by the integrated care team. Caregiver stress index was administered during the initial assessment and on the closing of active cases. The maximum score on this index is 13 with high stress classified as >7. Scores were added to a spreadsheet. This spreadsheet was reviewed, and relevant data was collated. One year assessed March 2021- March 2022.

Results

Carer stress information was collected on 62 of 112 identified complex cases (55%). Of these 55 of 96 individual patients were represented (57%). Average age 82 years old. 65% female and 35%, male. Range of carer stress scores observed 0- to 12. Of the 62 cases, 85% (53 cases) had a reduction in carer stress post-intervention(p<0.01). Of these 65% had a reduction below 7 (p<0.01). Mean score improvement 7. No carer stress indices disimproved post-treatment.

Conclusion

Multidisciplinary, patient-centred community care has a clear positive impact on the patient carer. Improvements in carer stress scores could be further evaluated as to the benefits of specific interventions in time. In future, a more large-scale collection and interpretation of data would need to occur for a more conclusive positive impact of the community based integrated care team to be confirmed.

51 VITAMIN D DEFICIENCY IS ASSOCIATED WITH INCREASED RISK OF ATRIAL FIBRILLATION: A CROSS-SECTIONAL ANALYSIS

Background

Atrial Fibrillation (AF) is prevalent (up to 10.9%) in Irish adults aged over 65 and significantly increases stroke risk, as well as being associated with greater stroke severity. Identifying potential contributing factors to development of AF offers opportunity for AF prevention and reduction in associated morbidity. Low vitamin D status has been associated with AF but studies are inconsistent. We aimed to assess the potential relationship between vitamin D deficiency and self-reported AF in older Irish adults.

Methods

Participants were from a large cross-sectional study of Irish adults aged >60 years, recruited from hospital outpatient services and GP practises. The diagnosis of AF was based on self-report so those with a Mini Mental State Examination (MMSE) <25 were excluded. Vitamin D deficiency was defined as a 25(OH)D <30 nmol/l. The relationship between deficiency and AF was explored in regression models.

Results

4264 participants, mean age 73.1± 8.0 years, female (67.4%) and 11.9% had AF. There was a higher prevalence of AF in those who were deficient vs non-deficient (17.2% vs 10.9%, P<0.0001). In a subsample (n = 4043), increased risk remained after adjusting for age, gender, season, vitamin D supplement use, body mass index, timed up and go, alcohol intake, smoking status, hypertension, diabetes, and heart disease (coronary artery disease and/or heart failure) (OR: 1.3, 1.1- 1.7 , P =0.023).

Conclusion

We identified that vitamin D deficiency was independently associated with a 30% increased likelihood of self-reported AF in older adults. Vitamin D is known to inhibit the renin angiotensin, aldosterone system which may play a role in both structural and electrical remodelling of the atrium. It may also have anti-inflammatory properties which could protect against AF. We were not able to distinguish between valvular and non-valvular AF though findings offer an interesting insight for potential further investigation.

314 COMMUNITY-BASED INTEGRATED CARE TEAMS EFFECTIVENESS IN PREVENTING CRISIS EMERGENCY DEPARTMENT ATTENDANCES

Background

Community based integrated care Multi-Disciplinary Teams (MDT) are a mainstay for future management of older adults. They have evolved to meet the needs of many different sub-types of clinical cases in the community. Complex Cases, are patients over 65 who reside within the catchment area, suffer from at least 2 frailty traits, and would be at increased risk of crisis emergency department (ED) attendance. Can the crisis ED attendances be prevented by integrated care team intervention?

Methods

The study population comprised adults identified as complex cases as per integrated care team standard operating procedure. Collated data was reviewed, and electronic medical records assessed as to whether any complex cases had been admitted within 30 days, 60 days, and 1 year of community team review. The study time frame was March 2021- to March 2022. As many patients have more than one unique identifying number, all patients were double-checked with an assessment based on their name and date of birth.

Results

112 complex cases were identified within one year, and 96 individual patients were represented. Average age 83 years old. 65% female and 35% male. 11% were admitted to hospital within 30 days, a further 6% were admitted within 60 days and by one year 30% of reviewed complex cases had been admitted to hospital.

Conclusion

In one year 70% of complex cases have been successfully maintained in the community. This has been achieved based on a multidisciplinary-based, patient-centred care approach. Given that 53% of hospital inpatient bed days are occupied by those over 65. This review concurs with previous research suggesting that an increase in community based integrated care teams is justified and should the aim for a fully staffed team per 150,000 patients over 65 come to fruition more than two-thirds of even the most complicated geriatric cases could be managed in the community.

261 HIGH FRACTURE RISK IN OLDER IRISH ADULT FALLERS

Background

Fracture risk due to falls depends on several factors including bone density, quality and size, hip geometry (axis length), direction of fall (forward, backwards or sideways), body mass index (BMI), type of surface impacted, body site of impact and mechanism of fall (eg syncope). We aimed to identify the fracture risk per fall in frail older Irish adults.

Methods

Participants were from the hypertensive and cognitive cohort of the Trinity, Ulster, Dept Agriculture (TUDA) study of Irish adults (aged >60) recruited from hospital outpatient services and GP practises. Falls and falls resulting in fracture in the previous year were self-reported so those with an MMSE < 25 were excluded to avoid recall bias. We identified fallers, recurrent fallers and fractures due to falls in the previous year.

Results

892 fallers, mean age 76.3 ± 8.4 yrs, 65.2% female. 23.8% had 2 falls and 24.2% ≥3 falls. Mean timed up and go was 17.3 ± 9.5 seconds. Commonest fracture due to falls were hip (20.1%), upper limb (18.5%) and lower limb (17.9%) with one fracture of neck and skull. Fracture rate per fall was 7.1%: 1.7% for hip, 1.3% for lower and 1.2% for upper limb. Annual fracture rate per faller was 16.5%. The only predictors of fall with fracture versus no fracture were female sex (OR 2.4, 1.6-3.6, P<0.001) and lower body mass index (P=0.001).

Conclusion

We identified similar hip fracture rates (1.7%) due to falls as in other studies. However, one in six fallers had sustained a fracture in the previous year reflecting the high proportion of recurrent fallers. Lower BMI and female sex predicted fall with fracture as both are strongly correlated with risk of osteoporosis. Recent guidelines now factor in recurrent falls when estimating the probability of future osteoporotic fractures.

Functional expression of NaV1.7 channels in freshly dispersed mouse bronchial smooth muscle cells

Isolated smooth muscle cells (SMC) from mouse bronchus were studied using the whole-cell patch clamp technique at ~21oC. Stepping from -100 mV to -20 mV evoked inward currents of mean amplitude -275 pA. These inactivated (tau=1.1 ms) and were abolished when external Na+ was substituted with N-Methyl-D-glucamine. In current-voltage protocols, current peaked at -10 mV and reversed between +20 and +30 mV. The V1/2s of activation and inactivation were -25 & -86 mV, respectively. The current was highly sensitive to tetrodotoxin (IC50=1.5 nM) and the NaV1.7 subtype selective blocker, PF-05089771 (IC50=8.6 nM), consistent with NaV1.7 as the underlying pore-forming a subunit. Two NaV1.7-selective antibodies caused membrane-delineated staining of isolated SMC, as did a non-selective pan-NaVantibody. RT-PCR, performed on groups of ~15 isolated SMC, revealed transcripts for NaV1.7 in 7/8 samples. Veratridine (30 mM), a non-selective NaV channel activator, reduced peak current evoked by depolarization but induced a sustained current of 40 pA. Both effects were reversed by tetrodotoxin (100 nM). In tension experiments veratridine (10 mM) induced contractions that were entirely blocked by atropine (1 mM). However, in the presence of atropine, veratridine was able to modulate the pattern of activity induced by a combination of U-46619 (a thromboxane A2 mimetic) & PGE2(prostaglandin E2), by eliminating bursts in favour of sustained phasic contractions. These effects were readily reversed to control-like activity by tetrodotoxin (100 nM). In conclusion, mouse bronchial SMC functionally express NaV1.7 channels that are capable of modulating contractile activity, at least under experimental conditions.

Fast voltage-dependent sodium (NaV ) currents are functionally expressed in mouse corpus cavernosum smooth muscle cells

BACKGROUND AND PURPOSE

Corpus cavernosum smooth muscle (CCSM) exhibits phasic contractions that are coordinated by ion channels. Mouse models are commonly used to study erectile dysfunction, but there are few published electrophysiological studies of mouse CCSM. We describe, for the first time, voltage-dependent sodium (Na_V ) currents in mouse CCSM and investigate their function.

EXPERIMENTAL APPROACH

Electrophysiological, pharmacological, and immunocytochemical studies on isolated CCSM cells. Tension measurements in whole tissue.

KEY RESULTS

A fast, voltage-dependent sodium current was induced by depolarising steps. Steady-state activation and inactivation curves revealed a window current between -60 and -30 mV. Two populations of Na_V currents, ('TTX-sensitive') and ('TTX-insensitive'), were distinguished. TTX-sensitive current showed 48% block with the Na_V -subtype-specific blockers ICA-121431 (Na_V 1.1-1.3), PF-05089771 (Na_V 1.7), and 4,9-anhydro-TTX (Na_V 1.6). TTX-insensitive current was insensitive to A803467, a Na_V 1.8 blocker. Immunocytochemistry confirmed the expression of Na_V 1.5 and Na_V 1.4 in freshly dispersed CCSM cells. Veratridine, a Na_V activator, reduced time-dependent inactivation of the current and increased the duration of evoked action potentials. Veratridine induced phasic contractions in CCSM strips. This effect was reversible with TTX and nifedipine but not by KB-R7943.

CONCLUSION AND IMPLICATIONS

We report, for the first time, a fast voltage-dependent sodium current in mouse CCSM. Stimulation of this current increases the contractility of corpus cavernosum in vitro, suggesting that it may contribute to the mechanisms of detumescence, and potentially serve as a clinically relevant target for pharmaceutical intervention in erectile dysfunction. Further work will be necessary to define its role.

Experiences of implant loss after immediate implant-based breast reconstruction: qualitative study

BACKGROUND

Immediate implant-based breast reconstruction (IBBR) is the most commonly performed reconstructive procedure in the UK, but almost one in ten women experience implant loss and reconstructive failure after this technique. Little is known about how implant loss impacts on patients' quality of life. The first phase of the Loss of implant Breast Reconstruction (LiBRA) study aimed to use qualitative methods to explore women's experiences of implant loss and develop recommendations to improve care.

METHODS

Semistructured interviews were conducted with a purposive sample of women who experienced implant loss after immediate IBBR, performed for malignancy or risk reduction across six centres. Interviews explored decision-making regarding IBBR, and experiences of implant loss and support received. Thematic analysis was used to explore the qualitative interview data. Sampling, data collection and analysis were undertaken concurrently and iteratively until data saturation was achieved.

RESULTS

Twenty-four women were interviewed; 19 had surgery for malignancy and five for risk reduction. The median time between implant loss and interview was 42 (range 22-74) months. Ten women had undergone secondary reconstruction, two were awaiting surgery, and 12 had declined further reconstruction. Three key themes were identified: the need for accurate information about the risks and benefits of IBBR; the need for more information about 'early-warning' signs of postoperative problems, to empower women to seek help; and better support following implant loss.

CONCLUSION

Implant loss is a devastating event for many women. Better preoperative information and support, along with holistic patient-centred care when complications occur, may significantly improve the experience and outcome of care.

Inhibitory effects of openers of large-conductance Ca2+-activated K+ channels on agonist-induced phasic contractions in rabbit and mouse bronchial smooth muscle

Airway smooth muscle expresses abundant BK_Ca channels, but their role in regulating contractions remains controversial. This study examines the effects of two potent BK_Ca channel openers on agonist-induced phasic contractions in rabbit and mouse bronchi. First, we demonstrated the ability of 10 μM GoSlo-SR5-130 to activate BK_Ca channels in inside-out patches from rabbit bronchial myocytes, where it shifted the activation V_1/2 by -88 ± 11 mV (100 nM Ca²⁺, n = 7). In mouse airway smooth muscle cells, GoSlo-SR5-130 dose dependently shifted V_1/2 by 12-83 mV over a concentration range of 1-30 μM. Compound X, a racemic mixture of two enantiomers, reported to be potent BK_Ca channel openers, shifted V_1/2 by 20-79 mV over a concentration range of 0.3-3 μM. In rabbit bronchial rings, exposure to histamine (1 μM) induced phasic contractions after a delay of ~35 min. These were abolished by GoSlo-SR5-130 (30 μM). Nifedipine (100 nM) and CaCC_inhA01 (10 μM), a TMEM16A blocker, also abolished histamine-induced phasic contractions. In mouse bronchi, similar phasic contractions were evoked by exposure to U46619 (100 nM) and carbachol (100 nM). In each case, these were inhibited by concentrations of GoSlo-SR5-130 and compound X that shifted the activation V_1/2 of BK_Ca channels in the order of -80 mV. In conclusion, membrane potential-dependent regulation of L-type Ca²⁺ channels appears to be important for histamine-, U46619-, and carbachol-induced phasic contractions in airway smooth muscle. Contractions can be abolished by BK_Ca channel openers, suggesting that these channels are potential targets for treating some causes of airway obstruction.

β3-adrenoceptor agonists inhibit carbachol-evoked Ca2+ oscillations in murine detrusor myocytes

OBJECTIVE

To test if carbachol (CCh)-evoked Ca²⁺ oscillations in freshly isolated murine detrusor myocytes are affected by β3-adrenoceptor (β-AR) modulators.

MATERIALS AND METHODS

Isometric tension recordings were made from strips of murine detrusor, and intracellular Ca²⁺ measurements were made from isolated detrusor myocytes using confocal microscopy. Transcriptional expression of β-AR sub-types in detrusor strips and isolated detrusor myocytes was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time quantitative PCR (qPCR). Immunocytochemistry experiments, using a β3-AR selective antibody, were performed to confirm that β3-ARs were present on detrusor myocytes.

RESULTS

The RT-PCR and qPCR experiments showed that β1-, β2- and β3-AR were expressed in murine detrusor, but that β3-ARs were the most abundant sub-type. The selective β3-AR agonist BRL37344 reduced the amplitude of CCh-induced contractions of detrusor smooth muscle. These responses were unaffected by addition of the BK channel blocker iberiotoxin. BRL37344 also reduced the amplitude of CCh-induced Ca²⁺ oscillations in freshly isolated murine detrusor myocytes. This effect was mimicked by CL316,243, another β3-AR agonist, and inhibited by the β3-AR antagonist L748,337, but not by propranolol, an antagonist of β1- and β2-ARs. BRL37344 did not affect caffeine-evoked Ca²⁺ transients or L-type Ca²⁺ current in isolated detrusor myocytes.

CONCLUSION

Inhibition of cholinergic-mediated contractions of the detrusor by β3-AR agonists was associated with a reduction in Ca²⁺ oscillations in detrusor myocytes.

Effects of new-generation TMEM16A inhibitors on calcium-activated chloride currents in rabbit urethral interstitial cells of Cajal

Interstitial cells of Cajal (ICC) isolated from the rabbit urethra exhibit Ca²⁺-activated Cl^- currents (I _ClCa) that are important for the development of urethral tone. Here, we examined if TMEM16A (ANO1) contributed to this activity by examining the effect of "new-generation" TMEM16A inhibitors, CACC_inh-A01 and T16A_inh-A01, on I _ClCa recorded from freshly isolated rabbit urethral ICC (RUICC) and on contractions of intact strips of rabbit urethra smooth muscle. Real-time quantitative PCR experiments demonstrated that TMEM16A was highly expressed in rabbit urethra smooth muscle, in comparison to TMEM16B and TMEM16F. Single-cell RT-PCR experiments revealed that only TMEM16A was expressed in freshly isolated RUICC. Depolarization-evoked I _ClCa in isolated RUICC, recorded using voltage clamp, were inhibited by CACC_inh-A01 and T16A_inh-A01 with IC₅₀ values of 1.2 and 3.4 μM, respectively. Similarly, spontaneous transient inward currents (STICs) recorded from RUICC voltage clamped at -60 mV and spontaneous transient depolarizations (STDs), recorded in current clamp, were also inhibited by CACC_inh-A01 and T16A_inh-A01. In contrast, spontaneous Ca²⁺ waves in isolated RUICC were only partially reduced by CACC_inh-A01 and T16A_inh-A01. Finally, neurogenic contractions of strips of rabbit urethra smooth muscle (RUSM), evoked by electric field stimulation (EFS), were also significantly reduced by CACC_inh-A01 and T16A_inh-A01. These data are consistent with the idea that TMEM16A is involved with CACCs in RUICC and in contraction of rabbit urethral smooth muscle.

Intellectual developmental disorders, autism, and schizophrenia spectrum: New boundaries in the neurodevelopmental perspective

Background and aim

Recent evidences of clinical overlap, familial co-aggregation, and shared genetic alterations support a neurodevelopmental deviation to represent a probable common vulnerability factor not only for the psychiatric disorders included in the meta-structure of neurodevelopmental disorders, but also for other major psychiatric disorders, including schizophrenia.

The present paper reviews the literature to identify (1) positive and negative implications of the increasing enlargement of the group of neurodevelopmental disorders and (2) most useful clinical aspect for re-defining diagnostic boundaries between syndromic groups.

Methods

The search purpose was reached through a systematic mapping of literature.

Results

The last years’ trend to increasingly enlarge the number of psychiatric features comprised in the autism spectrum should be better evaluated for potential negative impact on research and clinical resources for those autistic syndromes more reliable with Kanner's descriptions or associated with lower personal functioning profiles and different level of ID.

Crucial clinical aspects for the differentiation resulted to be age of onset, interest towards others, main positive symptoms, and anatomical anomalies of the central nervous system.

Conclusions

While on one hand the neurodevelopmental perspective might contribute to a better understanding of the multifactorial aetiopathogenetic mechanisms underlying many psychiatric disorders and provide new intervention strategies, on the other hand it might determine a premature abandonment of the traditional nosology and the appearance of very broad spectrum conditions covering all the range of current psychopathology.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Including non-dietary sources into an exposure assessment of the European Food Safety Authority: The challenge of multi-sector chemicals such as Bisphenol A

In the most recent risk assessment for Bisphenol A for the first time a multi-route aggregate exposure assessment was conducted by the European Food Safety Authority. This assessment includes exposure via dietary sources, and also contributions of the most important non-dietary sources. Both average and high aggregate exposure were calculated by source-to-dose modeling (forward calculation) for different age groups and compared with estimates based on urinary biomonitoring data (backward calculation). The aggregate exposure estimates obtained by forward and backward modeling are in the same order of magnitude, with forward modeling yielding higher estimates associated with larger uncertainty. Yet, only forward modeling can indicate the relative contribution of different sources. Dietary exposure, especially via canned food, appears to be the most important exposure source and, based on the central aggregate exposure estimates, contributes around 90% to internal exposure to total (conjugated plus unconjugated) BPA. Dermal exposure via thermal paper and to a lesser extent via cosmetic products may contribute around 10% for some age groups. The uncertainty around these estimates is considerable, but since after dermal absorption a first-pass metabolism of BPA by conjugation is lacking, dermal sources may be of equal or even higher toxicological relevance than dietary sources.

Muscarinic Receptor Induced Contractions of the Detrusor are Mediated by Activation of TRPC4 Channels

PURPOSE

Muscarinic receptor mediated contractions of the detrusor rely on Ca²⁺ influx through voltage-gated Ca²⁺ channels but to our knowledge the mechanism linking stimulation of M3Rs to the activation of voltage dependent Ca²⁺ channels has not been established. TRPC4 channels are receptor operated cation channels that couple muscarinic receptor activation to depolarization of intestinal smooth muscle cells, voltage-activated Ca²⁺ influx and contraction. We investigated whether TRPC4 channels are involved in cholinergic mediated contractions of the detrusor.

MATERIALS AND METHODS

Isometric tension recordings were made on strips of murine detrusor and intracellular Ca²⁺ measurements were made on isolated detrusor myocytes using confocal microscopy. Transcriptional expression of TRPC and IP₃R subtypes in intact detrusor strips and isolated detrusor myocytes was assessed using reverse transcriptase-polymerase chain reaction.

RESULTS

Cholinergic stimulation of the detrusor induced by electrical field stimulation or exogenous application of carbachol or neostigmine evoked contractions consisting of a transient plus a tonic response, which was blocked by ML204, an inhibitor of TRPC4 channels. A phasic oscillatory component was blocked by the IP₃R inhibitor 2-APB. Carbachol evoked reproducible Ca²⁺ responses in isolated detrusor myocytes, consisting of an initial Ca²⁺ transient followed by Ca²⁺ oscillations. ML204 inhibited the initial Ca²⁺ transient whereas 2-APB inhibited the Ca²⁺ oscillations. Reverse transcriptase-polymerase chain reaction experiments showed that TRPC4β, TRPC6 and IP₃R1 were selectively expressed in isolated detrusor myocytes. Control experiments demonstrated that ML204 did not affect L-type Ca²⁺ or BK current amplitude, caffeine induced Ca²⁺ transients or KCl induced contractions of the detrusor.

CONCLUSIONS

Muscarinic receptor mediated contractions of the detrusor involve the activation of TRPC4β channels.

Effect of a novel BKCa opener on BKCa currents and contractility of the rabbit corpus cavernosum

Large-conductance Ca2+-activated K+ (BKCa) channels are thought to play a key role in the regulation of corpus cavernosum smooth muscle (CCSM) excitability. Few BKCa channel openers have been accepted for clinical development. The effect of the novel BKCa channel opener GoSlo-SR5-130 on electrical activity in isolated rabbit CCSM cells and mechanical activity in strips of rabbit CCSM was examined. Single-channel currents were observed in inside-out patches. These channels were sensitive to Ca2+, blocked by penitrem A, and had a conductance of 291 ± 20 pS ( n = 7). In the presence of GoSlo-SR5-130, the number of open BKCa channels increased. Using voltage-ramp protocols, GoSlo-SR5-130 caused currents to activate at more negative potentials in a concentration-dependent manner, shifting the half-maximal activation voltage potential to the left on the voltage axis. Therefore, BKCa channels were open within the physiological range of membrane potentials in the presence of GoSlo-SR5-130. GoSlo-SR5-130 also resulted in an increase in the activity of spontaneous transient outward currents in myocytes isolated from CCSM, and this effect was reversed by iberiotoxin. In current-clamp mode, GoSlo-SR5-130 hyperpolarized the cell membrane. Isometric tension recording of strips of rabbit corpus cavernosum showed that GoSlo-SR5-130 inhibited spontaneous contractions in a concentration-dependent manner. This effect was reversed in the presence of iberiotoxin, suggesting that GoSlo-SR5-130 exerts its effect through BKCa channels. These findings suggest that GoSlo-SR5-130 is an effective tool for the study of BKCa channels and that these channels can modulate CCSM activity and are possible targets for the treatment of erectile dysfunction.

Using workload measurement tools in diverse care contexts: the experience of staff in mental health and learning disability inpatient settings

ACCESSIBLE SUMMARY

What is known on the subject? Difficulties with the recruitment and retention of qualified nursing staff have resulted in nursing shortages worldwide with a consequential impact on the quality of care. It is increasingly recommended that evidence-based staffing levels are central to the development of workforce plans. Due to a paucity of empirical research in mental health and learning disability services the staffing needs and requirements for these settings are undefined and the availability of tools to aid staffing decisions is limited. What this paper adds to existing knowledge? This paper provides a valuable insight into the practical uses of these tools as perceived by staff members with day-to-day experience of the requirements of mental health and learning disability wards. It reveals that while workload measurement tools are considered a valuable aid for the development of workforce plans, they are limited in their ability to capture all aspects of care provision in these settings. It further emphasizes the inapplicability of a one-shoe-fits-all approach for determining nurse staffing levels and the need for individual and customized workforce plans. What are the implications for practice? This study demonstrates that the development of tools for use in mental health and learning disability services is in its infancy, yet no tool that has been validated as such. It highlights the potential for workload measurement tools to aid staffing decisions; however, a more holistic approach that considers additional factors is needed to ensure robust workforce planning models are developed for these services.

INTRODUCTION

The critical challenge of determining the correct level and skill mix of nursing staff required to deliver safe and effective health care has become an international concern. It is recommended that evidence-based staffing decisions are central to the development of future workforce plans. Workforce planning in mental health and learning disability nursing is largely under-researched with few tools available to aid the development of evidence-based staffing levels in these environments.

AIM

It was the aim of this study to explore the experience of staff using the Safer Nursing Care Tool and the Mental Health and Learning Disability Workload Tool in mental health and learning disability environments.

METHOD

Following a 4-week trial period of both tools, a survey was distributed via Qualtrics online survey software to staff members who used the tools during this time.

RESULTS

The results of the survey revealed that the tools were considered a useful resource to aid staffing decisions; however, specific criticisms were highlighted regarding their suitability to psychiatric intensive care units and learning disability wards.

DISCUSSION

This study highlights that further development of workload measurement tools is required to support the implementation of effective workforce planning strategies within mental health and learning disability services.

IMPLICATIONS FOR PRACTICE

With increasing fiscal pressures, the need to provide cost-effective care is paramount within the services of the National Health Service. Evidence-based workforce planning is therefore necessary to ensure that appropriate levels of staff are determined. This is of particular importance within mental health and learning disability services due to the reduction in the number of available beds and an increasing focus on purposeful admission and discharge.

Pharmacological characterization of TMEM16A currents

Recent studies have shown that transmembrane protein 16 A (TMEM16A) is a subunit of calcium-activated chloride channels (CACCs). Pharmacological agents have been used to probe the functional role of CACCs, however their effect on TMEM16A currents has not been systematically investigated. In the present study, we characterized the voltage and concentration-dependent effects of 2 traditional CACC inhibitors (niflumic acid and anthracene-9-carboxcylic acid) and 2 novel CACC / TMEM16A inhibitors (CACC(inh)A01 and T16A(inh)A01) on TMEM16A currents. The whole cell patch clamp technique was used to record TMEM16A currents from HE K 293 cells that stably expressed human TMEM16A. Niflumic acid, A-9-C, CACC(inh)A01 and T16A(inh)A01 inhibited TMEM16A currents with IC50 values of 12, 58, 1.7 and 1.5 μM, respectively, however, A-9-C and niflumic acid were less efficacious at negative membrane potentials. A-9-C and niflumic acid reduced the rate of TMEM16A tail current deactivation at negative membrane potentials and A-9-C (1 mM) enhanced peak TMEM16A tail current amplitude. In contrast, the inhibitory effects of CACC(inh)A01 and T16A(inh)A01 were independent of voltage and they did not prolong the rate of TMEM16A tail current deactivation. The effects of niflumic acid and A-9-C on TMEM16A currents were similar to previous observations on CACCs in vascular smooth muscle, strengthening the hypothesis that they are encoded by TMEM16A. However, CACC(inh)A01 and T16A(inh)A01 were more potent inhibitors of TMEM16A channels and their effects were not diminished at negative membrane potentials making them attractive candidates to interrogate the functional role of TMEM16A channels in future studies.

Effects of the novel BK (KCa 1.1) channel opener GoSlo-SR-5-130 are dependent on the presence of BKβ subunits

BACKGROUND AND PURPOSE

GoSlo-SR compounds are efficacious BK (KCa 1.1) channel openers, but little is known about their mechanism of action or effect on bladder contractility. We examined the effects of two closely related compounds on BK currents and bladder contractions.

EXPERIMENTAL APPROACH

A combination of electrophysiology, molecular biology and synthetic chemistry was used to examine the effects of two novel channel agonists on BK channels from bladder smooth muscle cells and in HEK cells expressing BKα alone or in combination with either β1 or β4 subunits.

KEY RESULTS

GoSlo-SR-5-6 shifted the voltage required for half maximal activation (V1/2 ) of BK channels approximately -100 mV, irrespective of the presence of regulatory β subunits. The deaminated derivative, GoSlo-SR-5-130, also shifted the activation V1/2 in smooth muscle cells by approximately -100 mV; however, this was reduced by ∼80% in HEK cells expressing only BKα subunits. When β1 or β4 subunits were co-expressed with BKα, efficacy was restored. GoSlo-SR-5-130 caused a concentration-dependent reduction in spontaneous bladder contraction amplitude and this was abolished by iberiotoxin, consistent with an effect on BK channels.

CONCLUSIONS AND IMPLICATIONS

GoSlo-SR-5-130 required β1 or β4 subunits to mediate its full effects, whereas GoSlo-SR-5-6 worked equally well in the absence or presence of β subunits. GoSlo-SR-5-130 inhibited spontaneous bladder contractions by activating BK channels. The novel BK channel opener, GoSlo-SR-5-130, is approximately fivefold more efficacious on BK channels with regulatory β subunits and may be a useful scaffold in the development of drugs to treat diseases such as overactive bladder.

Disparities in cesarean delivery by ethnicity and nativity in New York city

Our objective was to examine differences in risk of cesarean delivery among diverse ethnic groups in New York City. Using cross-sectional New York City birth and hospitalization data from 1995 to 2003 (n = 961,381) we estimated risk ratios for ethnic groups relative to non-Hispanic whites and immigrant women relative to US-born women. Adjusting for insurance, pre-pregnancy weight, maternal age, education, parity, birthweight, gestational age, year, medical complications, and pregnancy complications, all ethnic groups except East Asian women were at an increased risk of cesarean delivery, with the highest risk among Hispanic Caribbean women [adjusted risk ratio (aRR) = 1.27, 95 % CI (confidence interval) = 1.24, 1.30] and African American women (aRR = 1.20, 95 % CI = 1.17, 1.23). Among Hispanic groups, immigrant status further increased adjusted risk of cesarean delivery; adjusted risk ratios for foreign-born women compared to US-born women of the same ethnic group were 1.27 for Mexican women (95 % CI = 1.05, 1.53), 1.23 for Hispanic Caribbean women (95 % CI = 1.20, 1.27), and 1.12 for Central/South American women (95 % CI = 1.04, 1.21). Similar patterns were found in subgroup analyses of low-risk women (term delivery and no pregnancy or medical complications) and primiparous women. We found evidence of disparities by ethnicity and nativity in cesarean delivery rates after adjusting for multiple risk factors. Efforts to reduce rates of cesarean delivery should address these disparities. Future research should explore potential explanations including hospital environment, provider bias, and patient preference.

Mechanisms underlying activation of transient BK current in rabbit urethral smooth muscle cells and its modulation by IP3-generating agonists

We used the perforated patch-clamp technique at 37°C to investigate the mechanisms underlying the activation of a transient large-conductance K(+) (tBK) current in rabbit urethral smooth muscle cells. The tBK current required an elevation of intracellular Ca(2+), resulting from ryanodine receptor (RyR) activation via Ca(2+)-induced Ca(2+) release, triggered by Ca(2+) influx through L-type Ca(2+) (CaV) channels. Carbachol inhibited tBK current by reducing Ca(2+) influx and Ca(2+) release and altered the shape of spike complexes recorded under current-clamp conditions. The tBK currents were blocked by iberiotoxin and penitrem A (300 and 100 nM, respectively) and were also inhibited when external Ca(2+) was removed or the CaV channel inhibitors nifedipine (10 μM) and Cd(2+) (100 μM) were applied. The tBK current was inhibited by caffeine (10 mM), ryanodine (30 μM), and tetracaine (100 μM), suggesting that RyR-mediated Ca(2+) release contributed to the activation of the tBK current. When IP3 receptors (IP3Rs) were blocked with 2-aminoethoxydiphenyl borate (2-APB, 100 μM), the amplitude of the tBK current was not reduced. However, when Ca(2+) release via IP3Rs was evoked with phenylephrine (1 μM) or carbachol (1 μM), the tBK current was inhibited. The effect of carbachol was abolished when IP3Rs were blocked with 2-APB or by inhibition of muscarinic receptors with the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (1 μM). Under current-clamp conditions, bursts of action potentials could be evoked with depolarizing current injection. Carbachol reduced the number and amplitude of spikes in each burst, and these effects were reduced in the presence of 2-APB. In the presence of ryanodine, the number and amplitude of spikes were also reduced, and carbachol was without further effect. These data suggest that IP3-generating agonists can modulate the electrical activity of rabbit urethral smooth muscle cells and may contribute to the effects of neurotransmitters on urethral tone.

The cardiac sodium current Na(v)1.5 is functionally expressed in rabbit bronchial smooth muscle cells

A collagenase-proteinase mixture was used to isolate airway smooth muscle cells (ASMC) from rabbit bronchi, and membrane currents were recorded using the whole cell patch-clamp technique. Stepping from -100 mV to a test potential of -40 mV evoked a fast voltage-dependent Na(+) current, sometimes with an amplitude of several nanoamperes. The current disappeared within 15 min of exposure to papain + DTT (n = 6). Comparison of the current in ASMC with current mediated by NaV1.5 α-subunits expressed in human embryonic kidney cells revealed similar voltage dependences of activation (V1/2 = -42 mV for NaV1.5) and sensitivities to TTX (IC50 = 1.1 and 1.2 μM for ASMC and NaV1.5, respectively). The current in ASMC was also blocked by lidocaine (IC50 = 160 μM). Although veratridine, an agonist of voltage-gated Na(+) channels, reduced the peak current by 33%, it slowed inactivation, resulting in a fourfold increase in sustained current (measured at 25 ms after onset). In current-clamp mode, veratridine prolonged evoked action potentials from 37 ± 9 to 1,053 ± 410 ms (n = 8). Primers for NaV1.2-1.9 were used to amplify mRNA from groups of ∼20 isolated ASMC and from whole bronchial tissue by RT-PCR. Transcripts for NaV1.2, NaV1.3, and NaV1.5-1.9 were detected in whole tissue, but only NaV1.2 and NaV1.5 were detected in single cells. We conclude that freshly dispersed rabbit ASMC express a fast voltage-gated Na(+) current that is mediated mainly by the NaV1.5 subtype.

An evaluation of team and individual formularies to support independent prescribing in mental health care

Mental health nurses have been entitled to train to become independent prescribers since May 2006; although the number of trained nurse prescribers seems to have increased steadily, a significant number of them have not actually undertaken prescribing roles on completion of their training or have limited their practice to supplementary prescribing. In order to support existing independent prescribers and to assist those nurses who have trained but are yet to prescribe independently, a mental health trust has piloted the use of individual and team formularies. An evaluation of this project indicated that formularies were well received by existing independent prescribers and were seen as a helpful instrument to support newly qualified and supplementary prescribers in their bid to become independent. Formularies can clarify and formalize each prescriber's area of competence, thus setting clear boundaries, reducing uncertainty and enhancing prescribers' confidence and willingness to take on this new role. Formularies may also be used to enhance communication with service users and further develop shared decision making. Effective procedures need to be in place to ensure formularies are up to date and reflect local practice.

Investigation of L-type Ca(2+) current in the aganglionic bowel segment in Hirschsprung's disease

BACKGROUND

Studies on animal models of Hirschsprung's disease (HD) suggest that L-type Ca(2+) channels are down-regulated in the aganglionic bowel segment, however, this has yet to be confirmed in HD patients. The objective of this study was to test the hypothesis that L-type Ca(2+) current density is decreased in smooth muscle cells (SMC) obtained from the aganglionic bowel segment of patients with HD in comparison with those from the ganglionic segment.

METHODS

Smooth muscle cells were freshly isolated from colon samples obtained from HD patients undergoing pull-through surgery. L-type Ca(2+) currents were recorded using the perforated patch configuration of the whole cell voltage clamp technique and the expression levels of CACNA1C transcripts (which encode L-type Ca(2+) channels) in the ganglionic and aganglionic bowel segments were compared using real-time quantitative PCR.

KEY RESULTS

All SMC displayed robust currents that had activation/inactivation kinetics typical of L-type Ca(2+) current, were inhibited by nifedipine and enhanced by the L-type Ca(2+) channel agonists FPL 64176 and Bay K 8644. Moreover, FPL 64176 activated currents were also inhibited by nifedipine. However, there was no significant difference in L-type Ca(2+) current density, CACNA1C subunit expression or sensitivity to the pharmacological agents noted above, between SMC isolated from the ganglionic and aganglionic regions of the HD colon.

CONCLUSIONS & INFERENCES

In contrast to studies on genetic animal models of HD, L-type Ca(2+) currents are not down-regulated in the aganglionic bowel segment of HD patients and are therefore unlikely to account for the impaired colonic peristalsis observed in these patients.

Strange beta: an assistance system for indoor rock climbing route setting

This paper applies the mathematics of chaos to the task of designing indoor rock-climbing routes. Chaotic variation has been used to great advantage on music and dance, but the challenges here are quite different, beginning with the representation. We present a formalized system for transcribing rock climbing problems and then describe a variation generator that is designed to support human route-setters in designing new and interesting climbing problems. This variation generator, termed strange beta, uses chaos to introduce novelty. We validated this approach with a large blinded study in a commercial climbing gym, in cooperation with experienced climbers and expert route setters. The results show that strange beta can help a human setter produce routes that are at least as good as, and in some cases better than, those produced in the traditional manner.

Contribution of Kv2.1 channels to the delayed rectifier current in freshly dispersed smooth muscle cells from rabbit urethra

We have characterized the native voltage-dependent K(+) (K(v)) current in rabbit urethral smooth muscle cells (RUSMC) and compared its pharmacological and biophysical properties with K(v)2.1 and K(v)2.2 channels cloned from the rabbit urethra and stably expressed in human embryonic kidney (HEK)-293 cells (HEK(Kv2.1) and HEK(Kv2.2)). RUSMC were perfused with Hanks' solution at 37°C and studied using the patch-clamp technique with K(+)-rich pipette solutions. Cells were bathed in 100 nM Penitrem A (Pen A) to block large-conductance Ca(2+)-activated K(+) (BK) currents and depolarized to +40 mV for 500 ms to evoke K(v) currents. These were unaffected by margatoxin, κ-dendrotoxin, or α-dendrotoxin (100 nM, n = 3-5) but were blocked by stromatoxin-1 (ScTx, IC(50) ∼130 nM), consistent with the idea that the currents were carried through K(v)2 channels. RNA was detected for K(v)2.1, K(v)2.2, and the silent subunit K(v)9.3 in urethral smooth muscle. Immunocytochemistry showed membrane staining for both K(v)2 subtypes and K(v)9.3 in isolated RUSMC. HEK(Kv2.1) and HEK(Kv2.2) currents were blocked in a concentration-dependent manner by ScTx, with estimated IC(50) values of ∼150 nM (K(v)2.1, n = 5) and 70 nM (K(v)2.2, n = 6). The mean half-maximal voltage (V(1/2)) of inactivation of the USMC K(v) current was -56 ± 3 mV (n = 9). This was similar to the HEK(Kv2.1) current (-55 ± 3 mV, n = 13) but significantly different from the HEK(Kv2.2) currents (-30 ± 3 mV, n = 11). Action potentials (AP) evoked from RUSMC studied under current-clamp mode were unaffected by ScTx. However, when ScTx was applied in the presence of Pen A, the AP duration was significantly prolonged. Similarly, ScTx increased the amplitude of spontaneous contractions threefold, but only after Pen A application. These data suggest that K(v)2.1 channels contribute significantly to the K(v) current in RUSMC.

Disengaging from acute inpatient psychiatric care: a description of service users' experiences and views

The growing number of people worldwide with mental health problems is increasing and making intensive demands on existing services. Recent reorganizations of healthcare provision in the UK have focused predominantly on administrative efficiency, standardization and cost-effectiveness. Although little evidence exists that reorganizations, per se, directly result in improved health nationally, nevertheless, organizational change coupled with improved care provision can have a considerable impact on the mental health of people. It is known that service users want person-centred help with improving their confidence, autonomy and cognitive and social skills so as to be able to manage their lives within the social context in which they live. In this study, semi-structured interviews were used to explore service users' expectations and experiences of acute inpatient care and the early post-discharge period. While the social environment of the wards was seen by many as conducive to promoting safety and interpersonal relationships, others found the experience lacking in assisting them to resume their lives post discharge. If acute care is to become more than a mechanism for addressing and containing risk, better targeted interventions are required to help individuals find strategies that are transferable to the context of their 'real' lives. A number of factors that were identified by respondents in this study are identified and discussed.

A comparison of outpatients with intellectual disability receiving specialised and general services in Ontario's psychiatric hospitals

BACKGROUND

This study compares outpatients with intellectual disability (ID) receiving specialised services to outpatients with ID receiving general services in Ontario's tertiary mental healthcare system in terms of demographics, symptom profile, strengths and resources, and clinical service needs.

METHODS

A secondary analysis of Colorado Client Assessment Record data collected from all tertiary psychiatric hospitals in the province was completed for a stratified random sample of 246 outpatients identified as having ID, from both specialised and general programmes.

RESULTS

Individuals with ID in specialised programmes differed from patients with ID in general programmes with regard to demographics, diagnostic profile, symptom presentation and recommended level of care.

CONCLUSIONS

Further research is required to determine why individuals access some services over others and to evaluate whether specialised services are more appropriate for certain subgroups with ID than others.

Nurse prescribing in mental health: national survey

Mental health nurses can now train to become independent prescribers as well as supplementary prescribers. Independent nurse prescribing can potentially help to reorganize mental health services, increase access to medicines and improve service user information, satisfaction and concordance. However, mental health nursing has been slow to undertake prescribing roles, and there has been little work conducted to look at where nurse prescribing is proving successful, and those areas where it is less so. This survey was designed to collect information from directors of nursing in mental health trusts about the numbers of mental health prescribers in England, gather views about prescribing in practice, and elicit intentions with regards to the development of nurse prescribing. In some Trusts, the number of mental health nurse prescribers has increased to the point where wider impacts on workforce, the configuration of teams and services are inevitable. Currently, the way that prescribing is used within different organizations, services and teams varies and it is unclear which setting is most appropriate for the different modes of prescribing. Future work should focus on the impact of mental health nurse prescribing on service delivery, as well as on service users, colleagues and nurses themselves.

Novel excitatory effects of adenosine triphosphate on contractile and pacemaker activity in rabbit urethral smooth muscle

PURPOSE

Adenosine triphosphate is thought to be an important neurotransmitter in urethral smooth muscle but its physiological role is still unclear. We characterized the effects of adenosine triphosphate on contractile and pacemaker activity in rabbit urethral smooth muscle.

MATERIALS AND METHODS

Tension recordings were made from strips of rabbit proximal urethral smooth muscle. Membrane currents from freshly isolated smooth muscle cells and interstitial cells of Cajal were recorded using the patch clamp technique. Intracellular Ca(2+) was measured using confocal microscopy.

RESULTS

Exogenous application of adenosine triphosphate (10 microM) evoked robust contractions that were inhibited by the type 2 purinergic receptor blocker suramin (100 microM) and the selective type 2 purinergic Y1 receptor antagonist MRS2500 (Tocris Bioscience, Ellisville, Missouri) (100 nM). Application of the type 2 purinergic Y receptor agonist 2-MeSADP (1 microM) mimicked the effects of adenosine triphosphate. When smooth muscle cells were studied under voltage clamp at -60 mV, adenosine triphosphate evoked a large single inward current (greater than 1.2 nA) but 2-MeSADP produced a small current (about 16 pA). In contrast, when interstitial cells of Cajal were held at -60 mV, they showed spontaneous transient inward currents that were increased in frequency by adenosine triphosphate and 2-MeSADP. These excitatory effects were inhibited by suramin and MRS2500. Interstitial cells of Cajal showed spontaneous Ca(2+) waves that were increased in frequency by adenosine triphosphate and 2-MeSADP. These effects were also inhibited by suramin and MRS2500.

CONCLUSIONS

Contractile effects of adenosine triphosphate in urethral smooth muscle are mediated by the activation of type 2 purinergic Y receptors on interstitial cells of Cajal.

Survey of psychiatrists' views of nurse prescribing

For mental health nurses and service users to realize the benefits of non-medical prescribing, psychiatrists need to understand the remit of this role and be actively involved in influencing it. Although healthcare policy in the UK supports the expansion of non-medical prescribing, it requires much more for the successful implementation of such initiatives in practice. The aim of this survey was to explore the attitudes of all grades of psychiatrist working in two mental health trusts in the West Midlands to nurse prescribing. A specifically designed questionnaire was sent out to two groups of psychiatrists to assess their attitudes towards non-medical prescribing. Psychiatrists (n = 147) completed and returned a specifically designed questionnaire of their views. The more senior doctors appeared less concerned about nurse prescribing. Junior doctors expressed equivocation towards the role, suggesting that nurse prescribers be consistently supervised and have limited access to mental health drugs. The findings from this study have considerable implications for teams if junior doctors hold different views to their senior colleagues. Without the assistance of trusts in facilitating role change, the introduction of new roles could potentially heighten conflict between professions.

A comparison of patients with intellectual disability receiving specialised and general services in Ontario's psychiatric hospitals

BACKGROUND

Over the years, the closure of institutions has meant that individuals with intellectual disabilities (IDs) must access mainstream (i.e. general) mental health services. However, concern that general services may not adequately meet the needs of patients with ID and mental illness has led to the development and implementation of more specialised programmes. This study compares patients with ID receiving specialised services to patients with ID receiving general services in Ontario's tertiary mental healthcare system in terms of demographics, symptom profile, strengths and resources and clinical service needs.

METHOD

A secondary analysis of Colorado Client Assessment Record data collected from all tertiary psychiatric hospitals in the province was completed for all 371 inpatients with ID, from both specialised and general programmes.

RESULTS

Inpatients in specialised programmes were more likely to have a diagnosis of mood disorder and were less likely to have a substance abuse or psychotic disorder. Individuals receiving specialised services had higher ratings of challenging behaviour than those in more general programmes. The two groups did not differ significantly in terms of recommended level of care, although more inpatients from specialised programmes were rated as requiring Level 4 care than inpatients from general programmes.

CONCLUSIONS

In Ontario, inpatients in specialised and general programmes have similar overall levels of need but unique clinical profiles that should be taken into consideration when designing interventions for them.

Role of mitochondria in modulation of spontaneous Ca2+ waves in freshly dispersed interstitial cells of Cajal from the rabbit urethra

Interstitial cells of Cajal (ICC) isolated from the rabbit urethra exhibit pacemaker activity that results from spontaneous Ca(2+) waves. The purpose of this study was to investigate if this activity was influenced by Ca(2+) uptake into mitochondria. Spontaneous Ca(2+) waves were recorded using a Nipkow spinning disk confocal microscope and spontaneous transient inward currents (STICs) were recorded using the whole-cell patch clamp technique. Disruption of the mitochondrial membrane potential with the electron transport chain inhibitors rotenone (10 microm) and antimycin A (5 microm) abolished Ca(2+) waves and increased basal Ca(2+) levels. Similar results were achieved when mitochondria membrane potential was collapsed using the protonophores FCCP (0.2 microm) and CCCP (1 microm). Spontaneous Ca(2+) waves were not inhibited by the ATP synthase inhibitor oligomycin (1 microm), suggesting that these effects were not attributable to an effect on ATP levels. STICs recorded under voltage clamp at -60 mV were also inhibited by CCCP and antimycin A. Dialysis of cells with the mitochondrial uniporter inhibitor RU360 (10 microm) also inhibited STICS. Stimulation of Ca(2+) uptake into mitochondria using the plant flavonoid kaempferol (10 microm) induced a series of propagating Ca(2+) waves. The kaempferol-induced activity was inhibited by application of caffeine (10 mm) or removal of extracellular Ca(2+), but was not significantly affected by the IP(3) receptor blocker 2-APB (100 microm). These data suggest that spontaneous Ca(2+) waves in urethral ICC are regulated by buffering of cytoplasmic Ca(2+) by mitochondria.