Impact of multidisciplinary team meetings on the management of patients with breast cancer in a large private healthcare facility

AIMS

Multidisciplinary meetings (MDMs) play a crucial role in decision-making in breast cancer patient care. This study aimed to firstly assess the impact of breast cancer MDMs in decision-making for breast cancer patients and secondly to determine the concordance between MDM recommendations and implementation of clinical practice.

METHODS

Patient cases to be presented at the weekly breast cancer MDMs were identified and prospectively enrolled. Management plans were predicted by the treating surgeon with the pre-MDM management plans then compared to MDM recommendations. Changes in decision-making were assessed in the following domains: further surgery, systemic therapy (endocrine, chemotherapy or targeted), radiotherapy, enrolment in a clinical trial, further investigations, and referral to other specialists or services. Patient records were subsequently reviewed at 3 months post-MDM to assess the rate of implementation of MDM recommendations and any reasons for discordance.

RESULTS

Out of 50 cases, 66% (CI 53-79%; p < .005) experienced a change in management plan as a result of MDM discussion, with a total of 66 episodes of recorded change per decision-making domain affecting the following: further surgery (7.6%), endocrine therapy (4.5%), chemotherapy (19.7%), targeted therapy (4.5%), radiotherapy (18.2%), enrolment for a clinical trial (12.1%), additional investigations (22.7%), and further referrals (10.6%). MDM recommendations were implemented in 83.7% of cases.

CONCLUSION

The breast cancer MDMs were found to substantially impact on the management plans for breast cancer patients, with 83.7% of MDM recommendations being implemented into clinical practice. This study reinforces the importance of MDMs in the management of these patients, as well as highlighting the need for further investigating and addressing the potential barriers to the implementation of MDM recommendations.

Silos and rigid processes: Barriers to the successful implementation of the Older prisoner Health and Social Care Assessment and Plan

Older adults are the fastest growing sub-group in prisons. They have complex health, social care and custodial needs and often the support they receive is sub-optimal. The Older prisoner Health and Social Care Assessment and Plan (OHSCAP) aimed to better meet these inter-related needs. As part of a wider study, a randomised controlled trial was conducted to evaluate the OHSCAPs effectiveness in meeting older prisoners' health, social care and custodial needs in comparison to treatment as usual. This article describes the nested qualitative study which aimed to explore the barriers and facilitators to the effective implementation of the OHSCAP. Semi-structured interviews were conducted with older adults (n = 14) and staff members t (n = 12). Data was analysed using the framework method. Three overarching key themes were identified. These were: (1) balancing care and custodial requirements; (2) prison, health and social care silos; and (3) rigid prison processes. Prison is an important opportunity to engage residents and improve public health. Cultural and strategic change is required for health, social care and custodial interventions, such as the OHSCAP, to be successfully implemented into prison settings.

Superconductivity from a melted insulator in Josephson junction arrays

Arrays of Josephson junctions are governed by a competition between superconductivity and repulsive Coulomb interactions, and are expected to exhibit diverging low-temperature resistance when interactions exceed a critical level. Here we report a study of the transport and microwave response of Josephson arrays with interactions exceeding this level. Contrary to expectations, we observe that the array resistance drops dramatically as the temperature is decreased-reminiscent of superconducting behaviour-and then saturates at low temperature. Applying a magnetic field, we eventually observe a transition to a highly resistive regime. These observations can be understood within a theoretical picture that accounts for the effect of thermal fluctuations on the insulating phase. On the basis of the agreement between experiment and theory, we suggest that apparent superconductivity in our Josephson arrays arises from melting the zero-temperature insulator.

Symmetry-broken Josephson junctions and superconducting diodes in magic-angle twisted bilayer graphene

The coexistence of gate-tunable superconducting, magnetic and topological orders in magic-angle twisted bilayer graphene provides opportunities for the creation of hybrid Josephson junctions. Here we report the fabrication of gate-defined symmetry-broken Josephson junctions in magic-angle twisted bilayer graphene, where the weak link is gate-tuned close to the correlated insulator state with a moiré filling factor of υ = -2. We observe a phase-shifted and asymmetric Fraunhofer pattern with a pronounced magnetic hysteresis. Our theoretical calculations of the junction weak link-with valley polarization and orbital magnetization-explain most of these unconventional features. The effects persist up to the critical temperature of 3.5 K, with magnetic hysteresis observed below 800 mK. We show how the combination of magnetization and its current-induced magnetization switching allows us to realise a programmable zero-field superconducting diode. Our results represent a major advance towards the creation of future superconducting quantum electronic devices.

Detecting Induced p±ip Pairing at the Al-InAs Interface with a Quantum Microwave Circuit

Superconductor-semiconductor hybrid devices are at the heart of several proposed approaches to quantum information processing, but their basic properties remain to be understood. We embed a two-dimensional Al-InAs hybrid system in a resonant microwave circuit, probing the breakdown of superconductivity due to an applied magnetic field. We find a fingerprint from the two-component nature of the hybrid system, and quantitatively compare with a theory that includes the contribution of intraband p±ip pairing in the InAs, as well as the emergence of Bogoliubov-Fermi surfaces due to magnetic field. Separately resolving the Al and InAs contributions allows us to determine the carrier density and mobility in the InAs.

Validation of the CARPREG II risk stratification model and the WHOm scale in pregnant women with heart disease

 

The physiological changes of pregnancy imply a state of haemodynamic stress, which increases the risk of maternal-fetal complications in women with cardiac pathology. Risk stratification models allow clinical decisions to be guided and optimal diagnostic, follow-up and management strategies to be established according to each estimated category in order to reduce adverse outcomes.

Objective

To validate the CARPREG II and WHOm risk prediction models in a population of pregnant women with heart disease.

Materials and methods

Validation and comparison study of a risk prediction model in a prospective cohort of pregnant women with heart disease assessed between 2016 and 2019 by a cardiobstetric team in an average income country. The CARPREG II score was established and patients were classified according to the WHOm risk scale. We assessed cardiovascular and perinatal outcomes and determined the calibration and level of discrimination of these tools.

Results

In a cohort of 328 pregnant women (27±7 years), 33% (n=110) had congenital heart disease, followed by arrhythmias in 30% (n=98), valvular pathologies in 14% (n=46) and cardiomyopathies in 9% (n=29). In 56% of the pregnancies, the route of delivery was caesarean section, 84% of these by obstetric indication. A cardiac event occurred in 15%, with left heart failure (5.3%) and arrhythmias (2.3%) being the most frequent. The frequency of maternal death of cardiac origin during the study was 1.6%. Neonatal outcomes occurred in 37% of gestations (preterm delivery (16%) and low weight for gestational age (8.4%)) and obstetric events in 12.5%: pregnancy-induced hypertension (9%) and postpartum haemorrhage (2.3%).

NYHA functional class III-IV or cyanosis (OR 12 95% CI 3.1 - 46.4) and left ventricular dysfunction (LVEF &lt;55%) (OR 3 95% CI 1 - 10.9) were the most statistically significant risk predictors. Discrimination of both models was adequate (AUC-ROC of 0.74 95% CI 0.64 - 0.84) for the CARPREG II risk index and 0.77 for the WHOm scale (95% CI 0.69 - 0.86) (Figure 2). Calibration is also good in the study population (Hosmer- Lemeshow goodness-of-fit 0.6 and 0.1, respectively). By including in the CARPREG II model the variables ejection fraction and pulmonary artery systolic pressure in their numerical and not dichotomised form, a discrete improvement in the predictive ability of the scale is evident (AUC-ROC 0.81 95% CI 0.71–0.91).

Conclusions

The CARPREG II and WHOm risk stratification models have good ability to discriminate the risk of adverse cardiac outcomes in pregnant women with heart disease and fit our population. To improve the predictive power of CARPREG II, the variables pulmonary hypertension and left ventricular dysfunction could be used numerically and not dichotomised as in the original model.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): San Vicente Foundation University Hospital, Cardio-obstetric Center

Contemporary women's secure psychiatric services in the United Kingdom: A qualitative analysis of staff views

WHAT IS KNOWN ON THE SUBJECT?: Three pilot UK-only Women's Enhanced Medium Secure Services (WEMSS) was opened in 2007 to support women's movement from high secure care and provide a bespoke, women-only service. Evidence suggests that women's secure services are particularly challenging environments to work in and staffing issues (e.g., high turnover) can cause difficulties in establishing a therapeutic environment. Research in this area has focused on the experiences of service users. Studies which have examined staff views have focused on their feelings towards women in their care and the emotional burden of working in women's secure services. No papers have made a direct comparison between staff working in different services. WHAT DOES THIS STUDY ADD TO EXISTING KNOWLEDGE?: This is the first study to explore the views and experiences of staff in the three UK WEMSS pilot services and contrast them with staff from women's medium secure services. Drawing upon data from eighteen semi-structured interviews (nine WEMSS, nine non-WEMSS), key themes cover staff perceptions of factors important for women's recovery and their views on operational aspects of services. This study extends our understanding of the experiences of staff working with women in secure care and bears relevance for staff working internationally, as well as in UK services. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: The study reveals the importance of induction and training for bank and agency staff working in women's secure services. Further, regular clinical supervision should be mandatory for all staff so they are adequately supported.

ABSTRACT

Introduction Women's Enhanced Medium Secure Services (WEMSS) is bespoke, gender-sensitive services which opened in the UK in 2007 at three pilot sites. This study is the first of its kind to explore the experiences of WEMSS staff, directly comparing them to staff in a standard medium secure service for women. The literature to date has focused on the experiences of service users or staff views on working with women in secure care. Aim This qualitative study, embedded in a multimethod evaluation of WEMSS, aimed to explore the views and experiences of staff in WEMSS and comparator medium secure services. Methods Qualitative interviews took place with nine WEMSS staff and nine comparator medium secure staff. Interviews focused on factors important for recovery, barriers to facilitating recovery and operational aspects of the service. Discussion This study provides a rare insight into the perspectives of staff working in UK women's secure services, an under-researched area in the UK and internationally. Findings suggest that the success of services, including WEMSS, is compromised by operational factors such as the use of bank staff. Implications for practice Comprehensive training and supervision should be mandatory for all staff, so best practice is met and staff adequately supported.

Multiplexing Superconducting Qubit Circuit for Single Microwave Photon Generation

We report on a device that integrates eight superconducting transmon qubits in λ / 4 superconducting coplanar waveguide resonators fed from a common feedline. Using this multiplexing architecture, each resonator and qubit can be addressed individually, thus reducing the required hardware resources and allowing their individual characterisation by spectroscopic methods. The measured device parameters agree with the designed values, and the resonators and qubits exhibit excellent coherence properties and strong coupling, with the qubit relaxation rate dominated by the Purcell effect when brought in resonance with the resonator. Our analysis shows that the circuit is suitable for generation of single microwave photons on demand with an efficiency exceeding 80%.

A comparative study of educational provision for children with neurogenetic syndromes: parent and teacher survey

BACKGROUND

A number of neurogenetic syndromes have a high association with special educational needs including fragile X syndrome (FXS), Prader-Willi syndrome (PWS), Williams syndrome (WS) and Velo-Cardio-Facial syndrome (VCFS). There is a paucity of research on educational provision for children affected by these syndromes.

METHOD

Parents (n = 381) and teachers (n = 204) of school-aged children with one of the four syndromes in the UK and Ireland were surveyed in a range of areas concerning the child's educational provision. Areas surveyed included school placement, views on the needs of children with the syndromes, desired changes to current provision and perceived teacher knowledge.

RESULTS

School placement in mainstream settings decreased with age in all of the syndromes. Males with the syndromes were more likely to be in specialised educational settings with the exception of WS. Teachers reported limited input on initial or subsequent training for all of the syndromes. The majority of teachers did not view the needs of children with syndromes as different from other children with intellectual disability (ID) although there were significant differences between the syndromes. Changes deemed necessary to provision by parents and teachers differed between the syndromes indicating the existence of perceptions of syndrome specific needs. The lowest perceived level of teacher knowledge was in the VCFS group.

CONCLUSION

The majority of teachers of children with neurogenetic syndromes report limited knowledge of the syndromes, but also a lack of belief that the children's needs are different from the majority of children with ID. Differences between the syndromes in some areas of provision suggest that a child's syndrome does impact on educational provision in some areas.

ASD, ADHD, mental health conditions and psychopharmacology in neurogenetic syndromes: parent survey

BACKGROUND

There are a number of neurogenetic syndromes with well described behavioural phenotypes including fragile X syndrome, Prader-Willi syndrome, Williams syndrome and velo-cardio-facial syndrome (VCFS). Autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and psychiatric conditions are often associated with the syndromes.

METHOD

Parents (n = 381) of school-aged children with one of the four syndromes in the UK and Ireland were asked whether their child had been professionally diagnosed with ASD, ADHD or a mental health condition. Parents were also asked whether their child had been prescribed medication for behavioural or psychiatric reasons.

RESULTS

The highest level of reported diagnoses of ASD and ADHD was in fragile X syndrome. In all syndrome groups, lower rates of diagnosis were reported in comparison to previously published research. Prescribing of medication for behavioural/psychiatric reasons was highest in fragile X syndrome although the highest usage of melatonin was in Williams syndrome.

CONCLUSION

Reasons for a lower recognition of ASD, ADHD and mental health conditions in clinical practice compared with research studies may include 'diagnostic overshadowing' due to presence of intellectual disability and a genetic syndrome. However, there may also be a lack of belief in the utility of such diagnoses in neurogenetic syndromes among relevant professionals and/or lack of access to professionals with sufficient expertise in the recognition of such diagnoses in those with neurogenetic syndromes. The low rates of prescribing of medication for behavioural/psychiatric reasons may reflect the low level of clinical diagnoses or lack of belief in the utility of psychopharmacology in this population.

Health and social care services for older male adults in prison: the identification of current service provision and piloting of an assessment and care planning model

Background

Older prisoners are the fastest growing subgroup in the English and Welsh prison estate. Existing research highlights that older prisoners have high health and social care needs and that, currently, these needs routinely remain unmet.

Objectives

(1) To explore the needs of men entering and leaving prison; (2) to describe current provision of services, including integration between health and social care services; and (3) to develop and pilot an intervention for identifying health and social care needs on reception into prison, ensuring that these are systematically addressed during custody.

Methods

The research programme was a mixed-methods study comprising four parts: (1) a study of all prisons in England and Wales housing older adult men, establishing current availability and degree of integration between health and social care services through a national survey and qualitative interviews; (2) establishing the health and social care needs of older men entering prison, including experiences of reception into custody, through structured (n = 100) and semistructured (n = 27) interviews; (3) the development and implementation of an intervention to identify and manage the health, social care and custodial needs of older men entering prison; and (4) exploration of the health and social care needs of older men released from prison into the community through qualitative interviews with older prisoners prior to and following discharge from prison. Descriptive statistics were produced for all quantitative data, and qualitative data were analysed using the constant comparison method.

Results

The number of older prisoner leads has increased in recent years but they do not all appear always to be active in their roles, nor in receipt of specialist training. Nearly half (44%) of establishments do not have an older prisoner policy. There is a lack of integration between health and social care services because of ambiguity regarding responsibility for older prisoners' social care. The responsible social service may be located a considerable distance from where the prisoner is held; in such instances, local social services do not co-ordinate their care. The most frequent unmet need on prison entry was the provision of information about care and treatment. Release planning for older prisoners was frequently non-existent.

Limitations

The study used a cut-off age of 60 years as the lower limit for the definition of an older prisoner; evidence has emerged that supports a redefinition of that cut-off to 50 years. Our study examined the care provided for men and this should be considered if contemplating using the Older prisoner Health and Social Care Assessment and Plan (OHSCAP) with older women in prison.

Conclusion

The OHSCAP, developed as part of this study, provided a feasible and acceptable means of identifying and systematically addressing older prisoners' health and social care needs. Future work will include the conduct of a randomised controlled trial to examine the impact of the OHSCAP in terms of improving a range of outcomes, including economic impact.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Identification and management of prisoners with severe psychiatric illness by specialist mental health services

BACKGROUND

The prevalence of mental disorders among prisoners is considerably higher than in the general population. This is an important public health issue as the vast majority of prisoners stay in custody for less than 9 months and, when not in prison, offenders' lifestyles are frequently chaotic, characterized by social exclusion, instability and unemployment. Multi-disciplinary mental health inreach services were introduced to target care towards prisoners with severe mental illness (SMI) in a similar way to that provided by Community Mental Health Teams outside prison. The aim was to establish the proportion of prisoners with SMI who were assessed and managed by prison mental health inreach services. Method A two-phase prevalence survey in six prisons in England measured SMI upon reception into custody. Case-note review established the proportion of those with SMI subsequently assessed and treated by inreach services.

RESULTS

Of 3492 prisoners screened, 23% had SMI. Inreach teams assessed only 25% of these unwell prisoners, and accepted just 13% onto their caseloads.

CONCLUSIONS

Inreach teams identified and managed only a small proportion of prisoners with SMI. Prison-based services need to improve screening procedures and develop effective care pathways to ensure access to appropriate services. Improved identification of mental illness is needed in both the community and the Criminal Justice System to better engage with socially transient individuals who have chaotic lifestyles and complex needs.

Effect of the oestrous cycle, pregnancy and uterine region on the responsiveness of the isolated mouse uterus to prostaglandin F(2alpha) and the thromboxane mimetic U46619

Previous studies in this laboratory have suggested that the isolated uterus from non-pregnant mice has a prostaglandin F and a thromboxane receptor population similar to that found in human myometrium. The aim of this study was to investigate any regional variation in myogenic activity ) and the and responsiveness to prostaglandin F(2alpha) (PGF(2alpha) thromboxane mimetic U46619 in the mouse uterus taken during different stages of the oestrous cycle and during pregnancy. Uterine samples from BKW mice were taken from different anatomical segments along the length of each uterine horn and set up for superfusion at 2 ml/min with Krebs solution (containing 1 microM indometacin) at 37 degrees C, and gassed with 95%O(2)/5%CO(2). Responses (area under the curve) are expressed as a percentage of the final contraction induced by hypotonic shock. Data are expressed as the means +/- s.e.m. of n=5-12 and were analysed using Student's paired t-test or two-way ANOVA with a Bonferroni post hoc test. Regional variation in myogenic activity was observed in all tissues studied except those taken during labour. These tissues displayed significantly greater myogenic activity than tissues taken at late gestation and at all stages of the oestrous cycle. Tissues from pregnant animals were generally more responsive to U46619 and PGF(2alpha) than tissues taken from non-pregnant animals. Tissues taken from the upper segment of the uterine horn were more responsive to both agonists during the oestrous cycle. The findings demonstrated that the hormonal milieu and site of excision are important for myogenic activity and responsiveness.

Clean intermittent self-catheterisation and children

The best chance for good renal health and continence for children with a neuropathic bladder is clean intermittent self-catheterisation. In order to maximize potential for good renal health and continence the child and family need to be well supported by the multidisciplinary team, making good use of the knowledge of the children's urology specialist nurse who is able to provide relevant information, advice and education. With support many children with a neuropathic bladder are able to achieve continence while maintaining good renal health.

The evaluation of interdigitated array electrodes for measurement of catecholamines and indoleamines

The use of Interdigitated Array (IDA) Microelectrodes for detection of low levels of biogenic amines has been demonstrated in stationary solutions and flow systems [M. Morita, et al., Electrochemica Acta 42 (20--21) (1997) 3177--3183]. This technique is highly sensitive. We have evaluated this technology as applied to High Pressure Liquid Chromatography with Electrochemical Detection (HPLC-EC) for analysis of microdialysate and tissue samples. With this new technology we demonstrated a x 10 fold increase in sensitivity in comparison to our existing technology. We are now able to detect dopamine at a level of 53 x 10(-18) moles on column and serotonin at 26 x 10(-18) moles on column. This technology now permits analysis of biogenic amines in samples from brain areas not previously amenable to this type of experiment.

A 23-year review of the management of acute retention of urine: progressing or regressing?

A retrospective review of all patients in Oxford under the care of one consultant urologist (GJF) who presented on alternate years over a 23-year period with acute retention of urine was undertaken. Data were collected on the: (i) number of patients discharged from hospital with an in-dwelling catheter; (ii) duration of catheter drainage prior to surgery; and (iii) duration of postoperative stay. In all, 244 patients underwent prostatectomy. Over the 23-year period, there was a significant increase in the proportion of patients discharged prior to surgery (P < 0.001) as well as their median duration of catheterisation (P < 0.001): more than 50% were catheterised for more than 3 months in 1997. Conversely, post-operative hospital stay has decreased. Prolonged catheter drainage carries considerable morbidity, with 72% experiencing some complication. Most patients feel they lose dignity, 69% consider it uncomfortable and more than 50% complain of burning sensations, bladder spasms and a persistent desire to micturate. We recommend that patients should not be placed on routine waiting lists where they are liable to remain for an unacceptably long time. Targets should be set to admit them within a set period and theatre lists made available. We feel that six weeks is a realistic target.

Capillary electrophoresis in the pharmaceutical industry: applications in discovery and chemical development

Over the last 10 to 15 years capillary electrophoresis (CE) has become an extensively used separation technique in the pharmaceutical industry. The attraction of the various modes of operation of CE to analysts is their complementarity to other more established methodology, in particular high-performance liquid chromatography. CE methods have been developed not only for the resolution of drug substances that vary widely in their structure, size and stereochemistry, but also for the determination of the physico-chemical constants of analytes, such as pKa and isoelectric point (pI) values, binding and complexation constants, and octanol-water partition coefficients.

The analysis of basic and acidic compounds using non-aqueous CE and non-aqueous CE-MS

It has been shown that non-aqueous capillary electrophoresis (NACE) can provide improved separations in comparison to those obtained using conventional CE under aqueous conditions (ACE). Previous work carried out in our laboratories involving initial investigations into the technique have been reported. Based on the findings of that work it was possible to separate a variety of basic pharmaceuticals from selected impurities and to obtain the successful separation of some hydrophobic sulphonic acids. The successful coupling of NACE to mass spectrometry (NACE-MS) has also been demonstrated.

Reducing thrombolytic therapy time delays in the emergency department

A 1 year (1995) retrospective audit of all patients who were discharged or died, with a primary diagnosis of acute myocardial infarction (AMI) was conducted at Auburn Hospital, a level 4 district hospital in Sydney's western suburbs. After their first echocardiogram (ECG), 21 patients of 129 patients who had a primary diagnosis of AMI in the Emergency Department at this time were given thrombolytic therapy. For eight patients there was a time delay of over 60 min to commencement of thrombolytic therapy. This time delay exceeded the Australian Council of Health-care Standards guidelines and was targeted as a quality improvement activity. The hospital cardiologist convened meetings of medical and nursing staff, to develop an action plan for reducing these delays. The strategies adopted, implemented between April and September 1996, involved (i) keeping the ECG machine in the emergency department at all times, (ii) installing a facsimile machine, (iii) keeping Alteplase (rt-PA) in the emergency department, (iv) staff education, (v) allowing senior medical staff to initiate treatment if the consultant was not readily contactable. Resulting from these initiatives time delays (after first ECG) were reduced from a median time of 55 min in 1995 to a median time delay of 43 min in 1997. This study highlights areas of unnecessary delay in patients receiving thrombolytic therapy and shows that these delays can be reduced by the implementation of relatively simple strategies by medical and nursing staff. Time delays from the development of symptoms (usually chest pain) to arrival at triage were recorded when such a time was specified in the clinical notes. The median delay from the development of chest pain to triage was 73 min.

Prostanoid-induced contraction of the rabbit isolated uterus is mediated by FP receptors

Natural and synthetic prostanoid agonists were used to study the prostanoid receptors involved in contraction of the mature, isolated uterus of virgin rabbits. The prostanoids elicited contractile responses with a rank order of potency of PGF2 alpha, fluprostenol > PGD2 > U-46,619 > PGE2 > carbaprostacyclin with mean EC50 (nM) values of 4, 6, 34, 550, 1318 and > 10,000, respectively. Carbachol, a muscarinic agonist given after the prostanoids to elicit a reference contraction, had a mean EC50 value of 1.1 microM. The results show that the mature rabbit uterus is most sensitive to prostaglandin FP agonists and, thus, can be defined pharmacologically as an FP receptor preparation. These findings may facilitative investigations into the possibility of different prostanoid receptor populations. In the absence of useful competitive FP receptor antagonists, agonist potency data is particularly useful in systems where cross-species comparisons and tissue-related factors are not involved. The potent activities of the FP agonists, PGF2 alpha and fluprostenol, in the isolated jugular vein and uterus of the rabbit suggest that these tissues may be useful for intra-species comparisons.

Characterisation of kinin receptors on the human isolated umbilical artery

The aim of this study was to determine the kinin responses on human umbilical artery (HUA) and to characterise the kinin receptors present on this tissue. The HUA was found to constrict in response to both the B2 receptor agonist, bradykinin (BK), and the B1 receptor agonist, des-Arg9-BK. The presence of indomethacin (2.79 microM) was found to have no significant effect on the responses to BK and des-Arg9-BK. The presence of the B2 receptor antagonist, HOE-140 (+2.79 microM indomethacin), resulted in a concentration-related rightward displacement of the concentration-effect curves to BK. The antagonism of the constrictor responses to BK by HOE-140 was found to be competitive (pA2 = 7.5). The responses to BK were not significantly affected by the B1 receptor antagonist des-Arg9(leu8)BK. The presence of des-Arg9(leu8)BK (+2.79 microM indomethacin) resulted in a concentration-related rightward displacement of the concentration-effect curve to des-Arg9-BK. The antagonism of the response to des-Arg9-BK by des-Arg9(leu8)BK was found to be competitive (pA2 = 5.9). The responses to des-Arg9-BK were not significantly affected by HOE-140. The results of the present study suggest that the products of the cyclooxygenase pathway are not involved in the kinin constrictor response on HUA and indicate the presence of B1 and B2 receptors on this tissue.

Pharmacological evidence for thromboxane receptor heterogeneity--implications for the eye

The pharmacological activity of two novel thromboxane A2 (TxA2)-mimetics, AGN191976 and AGN192093, was investigated in vitro, using standard organ bath assays and human platelets, to determine potency and selectivity at various prostanoid (PG-) receptors. The effects of these compounds on intraocular pressure in Beagle dogs were then compared with U-46619, a widely employed and structurally different TP-receptor agonist. AGN191976 and AGN192093 were highly potent TP-receptor agonists in the rat aorta (EC50 of 0.32 and 1.3 nM, respectively) and human myometrium. Both compounds were approximately 10 to 50 fold more potent than U-46619. These contractile responses could be blocked with a potent TP-receptor antagonist, SQ29548. In human platelets, AGN191976 (EC50 = 16.3 nM) and U-46619 (EC50 = 538.3 nM) potently stimulated aggregation (TP-receptor mediated effect), whereas AGN192093 was a much weaker agonist (EC50 = 37.9 microM). AGN192093 was not a partial agonist in platelets, since it did not antagonize aggregation induced by AGN191976, U-46619, arachidonic acid or ADP. These results provide evidence for a subdivision of TP-receptors, and AGN192093 appears to be able to distinguish between TP-receptors in smooth muscle and platelets. In the Beagle dog eye, both AGN191976 and AGN192093 were highly potent and efficacious ocular hypotensives. Single 2.5 micrograms doses of drug decreased IOP by 11.4 (AGN191976) and 7.7 mm Hg (AGN192093) relative to the contralateral control eye. In contrast, U-46619 did not lower IOP. AGN191976, but not U-46619, increased outflow facility in these animals, which is consistent with their effects on IOP. Neither compound caused miosis which is FP-receptor mediated in the dog. These studies suggest the existence of heterogeneous populations of TP-receptors. AGN191976 and AGN192093, two novel TP-receptor agonists, appear to be useful tools for the pharmacological distinction of TP-receptor subtypes.

A single intragastric pH electrode does not accurately measure intragastric acidity

OBJECTIVES

Recent studies have raised concerns about the validity of using a single intragastric pH electrode to measure gastric acidity accurately and reproducibly. The aim of this study was to compare simultaneous intragastric pH measurements obtained from an indwelling glass pH electrode to those determined by aspirations from the gastric pool and from ex vivo measurement.

METHODS

Twenty two normal volunteers were studied after fluoroscopically guided placement of a combined nasogastric tube-pH probe assembly. Simultaneous intragastric pH electrode and aspirate pH determinations were made basally for 120 min after administration of 15 ml of antacid (40 mEq buffering capacity) and for another 120 min an hour postprandially after administration of a second 15-ml dose of antacid. Gastric acid concentration (pH) measurements were recorded every 15 min during the following study protocols: 1) fasting baseline (30 min); 2) fasting antacid (120 min); 3) test meal (60 min); and 4) postprandial antacid (120 min).

RESULTS

Intragastric pH was consistently and significantly lower as measured by intragastric pH electrode than by aspiration. Baseline hydrogen ion concentration ([H+]) was 4.3 times higher by direct electrode measurement than by aspirate. Antacid-administered fasting decreased [H+] maximally at 15 min to 48% and 82% of baseline by electrode and aspiration, respectively. The minimal residual intragastric [H+] after fasting antacid was 12.4 times higher by electrode than by aspiration. Postprandial antacid maximally reduced [H+] by 46% at 15 min when recorded using an electrode compared with 60% at 30 min by aspiration. Correlation coefficients for intragastric electrode [H+] versus aspiration [H+] were 0.26 (p = 0.253), 0.61 (p < 0.001), 0.56 (p < 0.01), and 0.31 (p < 0.001), for baseline, fasting antacid, meal, and postprandial antacid, respectively.

CONCLUSIONS

Quantitative evaluations of intragastric acidity (pH) using an intragastric pH electrode and aspiration of gastric juice may yield remarkably different results. Studies that rely on a single intragastric electrode to quantitate intragastric acidity may be highly inaccurate.

A preliminary study of prostaglandin release by bradykinin (BK) on isolated human myometrium

The aim of this study was to investigate whether the response to BK on isolated human myometrium from non-pregnant (NP) and pregnant (P) donors involves the release of prostaglandin I2 (PGI2) and/or of PGE2. BK was injected as a bolus dose into the flow of the superfusate. The perfusate was collected during a response to BK and PG concentration measured by enzymoimmunoassay for PGE2 or PGI2. The BK response was biphasic, consisting of contraction followed by inhibition of myogenic activity. In tissues from both NP and P donors BK was found to cause a dose related release of PGE2 and PGI2. BK evoked PGE2 release which was greater during the contractile response than in the inhibitory response. Following the same dose of BK, PGI2 release was found to be greater in the inhibitory response than in the contractile phase. The findings indicate that in isolated human myometrium the response to BK does involve the release of PGE2 and PGI2 and in both NP and P tissue PGE2 release is greater in the contractile response phase whilst PGI2 predominates the inhibitory phase.

Investigation into the role of cyclooxygenase products in the bradykinin response on isolated human myometrium and umbilical artery

The aim of this study was to investigate the response to bradykinin (BK) on human myometrium and umbilical artery with respect to cyclo-oxygenase (CO) products. Dose/concentration response curves to BK were performed +/-2.79 microM indomethacin. On human myometrium the response to BK (0.001-50 nmol) was biphasic and consisted of a dose-related increase in myometrial tension which was followed by a period of inhibition of myogenic activity. In tissues from P donors the presence of indomethacin had no significant effect on the excitatory response, but the inhibitory component of the response was reduced. In tissues from NP donors indomethacin significantly enhanced the BK effect at higher doses and the inhibitory component of the response was reduced. On the HUA cumulative addition of BK (1-1000 nM) resulted in dose dependent constriction with desensitisation at the highest dose (EC50 = 38 nM). The presence of indomethacin had no significant effect on BK response on HUA. These findings suggest that CO products contribute significantly to response to BK on the human myometrium but not on HUA and that different CO products are produced by P and NP tissue.

Comparison of the effects of bradykinin and related compounds on isolated mouse and human uterus

The purpose of this study was to investigate and compare the response of the isolated human myometrium (non-pregnant donors) and mouse uterus to bradykinin (BK), Lys-BK and des-Arg9-BK (+/-2.79 microM indomethacin). The uterine strips were set up for superfusion using Kerbs' solution. On the human myometrium the responses to BK and Lys-BK were biphasic and consisted of an increase in myometrial tension which was followed by a period of inhibition of myogenic activity. Des-Arg9-BK evoked a monophasic contractile response. On the mouse uterus the responses to BK, Lys-BK and des-Arg9-BK were monophasic and contractile only. On both of the tissues the contractile responses to BK and Lys-BK were bell shaped and indomethacin abolished the bell-shaped part of the dose response curves. The response to des-Arg9-BK and the inhibitory response to BK and Lys-BK, on the human tissue, was also significantly reduced in the presence of indomethacin. The results of this study suggest that the human and mouse uterus do posses kinin receptors of the B2 type but on human myometrium these are biphasic responses.

Evidence for human thromboxane receptor heterogeneity using a novel series of 9,11-cyclic carbonate derivatives of prostaglandin F2 alpha

1. The pharmacological activity of a novel series of 9,11-cyclic carbonate derivatives of prostaglandin F2 alpha (PGF2 alpha) was investigated in various isolated smooth muscle preparations possessing different prostanoid receptor subtypes as well as in human platelets. Since subdivision of thromboxane (TP-) receptors into vascular/smooth muscle and platelet subtypes is a controversial subject, our studies included a human smooth muscle preparation (myometrium) in addition to the widely used rat aorta and human platelets as TP-receptor preparations. 2. Two members of that series, AGN191976 and AGN192093 were found to be highly potent and selective thromboxane-mimetics. AGN191976 and AGN192093 contracted isolated tissues of the rat thoracic aorta with EC50 values of 0.32 +/- 0.08 and 1.30 +/- 0.53 nM, respectively. Both agonists were at least 10 times more potent than the benchmark TP-agonist, U-46619, in this preparation, whilst being at least 500 times less potent at other prostanoid receptors (DP, EP1, EP3, FP, IP) in vitro. 3. In human myometrial strips from pregnant and non-pregnant donors, both AGN191976 and AGN192093 were potent contractile agonists. The rank order of potency in myometrium of AGN191976 > AGN192093 > U-46619 correlated well with that in the rat aorta. In human platelet-rich plasma (PRP), however, AGN191976 had potent proaggregatory activity (EC50 = 16.3 +/- 1.4 nM), which is a TP-receptor-mediated event, whereas AGN192093 was a much weaker agonist (EC50 = 37.9 +/- 2.0 microM). AGN192093 did not behave as an antagonist in the platelets, since it did not antagonize platelet aggregation induced by ADP, arachidonic acid, U-46619 or AGN191976. In human washed platelets, the activity profile of AGN191976 (EC50 = 4.15 +/- 0.52 nM) and AGN192093 (no aggregation up to 10 microM) was similar to that obtained in PRP. 4. The involvement of TP-receptors was verified with the potent TP-antagonist, SQ29548. SQ29548 (0.1 microM in myometrium; 1 microM in aorta; 1 microM and 10 microM in platelets) antagonized responses to U-46619, AGN191976 and AGN192093 as expected. 5. In conclusion, AGN191976 and AGN192093, both 9,11-cyclic carbonate derivatives of PGF2 alpha, were found to be highly potent and selective thromboxane-mimetics in rat vascular and human myometrial smooth muscle. However, only AGN 191976 was a potent agonist at TP-receptors in human platelets. The differential activity of AGN192093 on TP-receptor-mediated events in platelets and smooth muscle provides further evidence for a subdivision of TP-receptors. AGN192093 appears to be a useful tool for the pharmacological distinction of TP-receptor subtypes.

Characterization of the prostanoid receptors mediating constriction and relaxation of human isolated uterine artery

1. This study was undertaken to characterize pharmacologically the prostanoid receptor subtypes mediating constriction and relaxation of human isolated uterine artery. 2. U-46619 was a potent constrictor agonist on human uterine artery (EC50 [95% CL] = 3.5 [1.8-6.7] nM). Prostaglandin E2 (PGE2), PGF2 alpha, PGD2 and PGI2 only weakly constricted the uterine artery, being at least 100 times less potent than U-46619. The PGE2 and PGI2 constrictor effects may be modified by the potent dilator effects of these compounds. A number of agonists which show selectivity for FP-, DP- and EP-receptors including ICI 81008, BW 245C, sulprostone, rioprostil and butaprost, failed to cause any constriction at concentrations up to 30 microM. 3. Constrictor responses induced by all agonists tested were reduced or abolished by the TP-receptor blocking drugs, GR 32191 and EP 092. pA2 estimates for both antagonists versus U-46619 were 8.50, values which are consistent with their affinities at TP-receptors. 4. In preparations pre-constricted with phenylephrine (1 microM) both PGI2 and PGE2 were potent relaxant agonists. The selective IP-receptor agonists, cicaprost and iloprost, also dilated human uterine artery and were approximately 10 fold more potent than PGI2. The EP2-receptor agonists, butaprost and rioprostil and the selective DP-agonist, BW 245C, were at least 100 fold weaker than PGI2 and PGE2 suggesting that neither DP- nor EP2 receptors were involved. 5. We conclude that TP-receptors mediate constriction, whereas IP- and possibly EP4-receptors mediate relaxation of human uterine artery.

L-trans-pyrrolidine-2,4-dicarboxylate and cis-1-aminocyclobutane-1,3-dicarboxylate behave as transportable, competitive inhibitors of the high-affinity glutamate transporters

The ability of two conformationally restricted analogues of L-glutamate to function as non-transportable inhibitors of plasma membrane L-glutamate transport was investigated in primary cultures of cerebellar granule cells and cortical astrocytes. L-trans-Pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) and cis-1-aminocyclobutane-1,3-dicarboxylic acid (cis-ACBD) behaved as linear competitive inhibitors of the uptake of D-[3H]aspartate (used as a non-metabolizable analogue of L-glutamate) exhibiting Ki values between 40 and 145 microM; L-trans-PDC being the more potent inhibitor in each preparation. However, both L-trans-PDC and cis-ACBD, over a concentration range of 1 microM-5 mM, dose-dependently stimulated the release of exogenously supplied D-[3H]aspartate from granule cells maintained in a continuous superfusion system. The stimulated release was independent of extracellular calcium ions; essentially superimposable dose-response profiles being obtained in the absence and presence of 1.3 mM CaCl2 and yielding EC50 values of 16-25 microM and 180-220 microM for L-trans-PDC and cis-ACBD, respectively. Stimulated release of D-[3H]aspartate was unaffected by either 300 microM D-(-)-2-amino-5-phosphonopentanoic acid [D-APV; a selective antagonist of the N-methyl-D-aspartate (NMDA) receptor] or by 25 microM 6-cyano-7-nitroquinoxaline-2,3-dione [CNQX; a selective antagonist of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor]. The release of D-[3H]-aspartate following stimulation by either L-trans-PDC or cis-ACBD was however markedly attenuated following substitution in the superfusion medium of sodium ions by choline ions. Taken together, these results support an action of L-trans-PDC and cis-ACBD consistent with that of being competitive substrates rather than non-transportable blockers of the plasma membrane L-glutamate uptake system.

The Domiciliary Rehabilitation and Support Program. Rationale, organisation and outcome

OBJECTIVE

To describe the Domiciliary Rehabilitation and Support Program (whose principles are early surgery, rapid mobilisation, avoidance of sedation, and early discharge with physiotherapy and nursing support provided in the home) for elderly patients with proximal femoral fractures (PFF), and to compare its costs with those of a conventional approach to the problem.

DESIGN AND SETTING

Prospective data accumulation on all patients admitted to a major metropolitan teaching hospital (Sir Charles Gairdner Hospital).

PATIENTS

Six hundred and fifteen patients, 60 years or more, 76% female (mean age 82.6 +/- 8.1 years), 24% male (mean age 79.9 +/- 7.6 years).

RESULTS

The mean length of hospital stay of patients on the program was 18.9 (+/- 27.3) days compared with 28 days for elderly PFF patients in the preceding year. The morbidity and mortality figures were comparable with or better than other published series. There was a 15% financial saving following introduction of the scheme.

CONCLUSION

The Domiciliary Rehabilitation and Support Program is a safe and cost effective method of dealing with elderly patients suffering from a proximal femoral fracture.

In vitro characterization of prostanoid receptors on human myometrium at term pregnancy

1. Prostanoid receptors present on the pregnant human myometrium in vitro have been characterized according to the receptor classification proposed by Coleman et al. (1984) using natural prostanoids and synthetic, selective analogues and antagonists where available. 2. Prostaglandin E2 (PGE2) produced a biphasic effect consisting of an initial excitation followed by a dose-related inhibition. The EP2/EP3-receptor agonists, rioprostil and misoprostol, produced similar effects to PGE2, however, the excitatory event of the misoprostol response was related to dose. The EP1/EP3-receptor agonist, sulprostone, evoked a purely excitatory response which was unaffected by AH6809. The selective EP2-receptor agonist butaprost produced a long-lasting dose-dependent inhibition of activity. The results from these prostanoids indicated that inhibitory EP2- and excitatory EP3-receptors are present on myometrium from pregnant donors at term. 3. PGF2 alpha and the synthetic FP-receptor agonist, fluprostenol, caused equipotent excitatory effects, indicating the presence of contractile FP-receptors. 4. PGD2 produced a biphasic effect of which the inhibition appeared dose-related and was antagonized by the selective DP-receptor antagonist BW A868C. The selective DP-receptor agonist, BW245C, produced a potent inhibitory effect that was competitively antagonized by BW A868C (pA2 = 8.6). 5. PGI2 produced a biphasic response qualitatively similar to PGE2. The EP1/IP-receptor agonist, iloprost, produced an occasional unquantifiable excitation and dose-related inhibition. The selective IP-receptor prostanoid, cicaprost, evoked only an inhibitory response. 6. The stable thromboxane A2 (TXA2)-mimetic, U46619, produced potent excitation which was competitively antagonized by the TP-receptor antagonist, GR32191 (pA2 = 7.2). 7. The prostanoids tested indicate that a heterogeneous population of prostanoid receptors are presen ton human myometrium from pregnant donors. It may be concluded that excitation is EP3-, FP- and TP-receptor-mediated and inhibition is EP2-, DP- and IP-receptor-mediated. Comparison of data obtained from non-pregnant specimens indicates that the lower segment tissue from pregnant donors demonstrated more pronounced responses to EP2 and IP-receptor activation.

A comparison of the uterotrophic response in cyclic and ovariectomized normotensive and spontaneously hypertensive rats

The uterotrophic response in the normotensive (CD) and the hypertensive (SHR) rat was compared in intact cyclic rats and in ovariectomized rats given oestradiol. The parameters measured were blood flow, and uterine wet and dry weights. In the cyclic animals blood flow to the oestogen target tissue varied throughout the oestrous cycle, peak flows being achieved at pro-oestrus; in the SHR rat, however, the pro-oestrous maximum was significantly attenuated compared with the CD rat. Uterine wet and dry weights were similar. The temporal response to oestradiol in ovariectomized rats showed that in the CD rat the hyperaemic response peaked earlier than in the SHR rat, significant changes in terms of increased water imbibition also occurred more quickly in the CD strain. In both strains, uterine dry weight was the last parameter to be significantly increased, the maximum weight being attained more quickly in the SHR rat. The results of this study indicated that it is the blood flow to the oestrogen target tissues of the uterus and vagina that is most susceptible to change with strain of rat.

The role of thromboxane in the uterotrophic response in the gravid normotensive and spontaneously hypertensive rat

The role of thromboxane in the gravid normotensive (CD) and hypertensive (SHR) rat was investigated (by utilizing two thromboxane receptor-blocking drugs, EP092 and AH23848) both at mid-gestation and at term. The parameters examined were uterine blood flow (blood flows were measured by the microsphere technique) and uterine weight and placental blood flow at term, fetal mass and number. At mid-gestation EP092 significantly (P < 0.005) increased uterine blood flow in both strains whilst the increases seen with AH23848 were not statistically significant. At term (day 22 in the CD and day 23 in the SHR rat) the antagonists increased uterine blood flow in the CD rats alone. However, at this time the antagonists caused an increase in placental blood flow in both strains. Thromboxane appears to be involved in the regulation of uteroplacental blood flow. The observation that the antagonists were able to potentiate blood flow by mid-gestation may provide a clinical indication with respect to potential prophylactic use of this class of compounds in cases of pregnancy-induced hypertension in women.

In vitro characterization of prostanoid FP-, DP-, IP- and TP-receptors on the non-pregnant human myometrium

1. Prostaglandin F (PGF), PGD, PGI and thromboxane A2 (TXA2) receptors have been pharmacologically characterized on the non-pregnant human myometrium in vitro in accordance with the receptor classification proposed by Coleman et al. (1984). The tools for the classification include both natural prostanoids, synthetic, selective analogues and antagonists where available. 2. The potent excitatory actions of the natural FP-receptor prostanoid, PGF2 alpha, and the synthetic analogue, fluprostenol, indicate the presence of FP-receptors mediating contraction on the human myometrium. 3. PGD2 produced a biphasic response consisting of excitation followed by relaxation of spontaneous activity of the myometrium. The selective DP-receptor agonists, BW245C, produced purely inhibitory responses illustrating the presence of inhibitory DP-receptors in this tissue. The inhibitory responses of both PGD2 and BW245C were antagonized by the competitive DP-receptor antagonist, BWA 868C, providing conclusive evidence for the existence of DP-receptors. 4. PGI2 produced a biphasic response similar to PGD2. Iloprost, the EP1/IP-receptor agonist also produced a biphasic response, whilst the IP-receptor selective agonist, cicaprost, caused inhibition only, suggesting that inhibitory IP-receptors exist in the non-pregnant human myometrium. 5. The TXA2-mimetic, U46619, produced marked stimulation of the non-pregnant human myometrium and was approximately equipotent to PGF2 alpha and fluprostenol in this effect. The actions of U46619 were competitively antagonized by the TP-receptor antagonist GR32191 showing that excitatory TP-receptors exist in this tissue.6. All prostanoids tested, both natural and synthetic, had activity on the non-pregnant human myometrium in vitro, supporting the existence of a heterogeneous population of prostanoid receptors in this tissue. If the results from the present study are combined with those previously reported for EP-receptor agonists (Senior et al., 1991), it may be concluded that excitation may occur through FP-, TP-, EP3- and few EP,-receptors, whereas inhibition may occur through DP-, IP- and EP2-receptors.

The effects of thromboxane receptor antagonists on oestrogen-induced uterotrophic responses in the spontaneously hypertensive rat

1. The possible role of thromboxane in the uterotrophic response to oestrogen, in the spontaneously hypertensive rat was investigated by use of the thromboxane receptor antagonists EP092, AH23848 and BM 13.505. 2. The parameters studied were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3. The antagonists attenuated oestradiol-induced uterine blood flow and significantly reduced both wet and dry uterine weight. These changes were accompanied by decreases in nuclear oestrogen receptor levels. 4. The results suggest a supportive role for thromboxane in oestradiol-induced uterine growth.

Modification of the rat uterine response to oestrogen and tamoxifen by thromboxane antagonists

1. The thromboxane receptor antagonists EP092, AH23848 and BM 13.505 were used to investigate the role of thromboxane in the uterotrophic response to oestradiol and tamoxifen. 2. The parameters examined were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3. Only EP092 potentiated the hyperaemic response to oestrogen but all three thromboxane antagonists inhibited oestradiol-stimulated uterine growth. This inhibition was accompanied by a decrease in nuclear oestrogen receptor concentration. 4. The uterotrophic response to tamoxifen was unaffected by the thromboxane antagonists. 5. The mechanism by which the thromboxane antagonists may be exerting their growth inhibitory effect is discussed, although, whether this effect can be attributed to blockade of thromboxane receptors or to some other mechanism is not clear from this study.

In vitro characterization of prostanoid EP-receptors in the non-pregnant human myometrium

1. Prostaglandin receptors of the PGE type have been characterized in the non-pregnant human myometrium in vitro according to the scheme of Coleman et al. (1984) by use of the agonists PGE2, sulprostone, rioprostil, AY23626, butaprost, misoprostol, 16,16-dimethylprostaglandin E2, enprostil and iloprost, and, the antagonist AH6809. 2. All prostanoids tested were active in non-pregnant human myometrium either as stimulators and/or inhibitors of spontaneous activity or both. Biphasic responses to PGE2 indicate that at least two receptor types of the EP-receptor exist, one mediating relaxation and the other mediating contraction. 3. Further evidence for the EP-receptor mediating excitation and relaxation was provided by the action of the EP2-/EP3-receptor selective prostanoids rioprostil, AY23626 and misoprostol, and the EP1-/EP2-receptor selective agonist 16,16-dimethylprostaglandin E2. 4. Butaprost, an EP2-receptor selective agonist, produced potent inhibition of spontaneous activity in the tissue which was generally longer-lasting than that evoked by the natural prostanoid PGE2. 5. The EP1-/EP3-receptor selective agonist sulprostone and the EP3-receptor agonist enprostil produced potent contractile responses supporting the presence of contractile EP3-receptors in the non-pregnant human myometrium in vitro. 6. The EP1-/IP-receptor selective agonist, iloprost, produced mixed responses in non-pregnant human myometrium. The contractile response was inhibited by the EP1-receptor antagonist AH6809. However, responses to the EP1-/EP3-receptor selective agonist sulprostone were unaffected by AH6809 which may indicate that only a small population of EP1-receptors is present. 7. Therefore it would seem that a heterogeneous population of EP-receptors is present in the non-pregnant human myometrium.

Influence of surface hydrophilicity of liposomes on their interaction with plasma protein and clearance from the circulation: studies with poly(ethylene glycol)-coated vesicles

Well-defined liposome systems have previously established the influence of size, surface charge lipid composition and surface ligands, on in vivo fate and behaviour of model compounds entrapped in liposomes. In the present study, preformed liposomes which quantitatively retain aqueous markers were covalenty coupled via dipalmitoylphosphatidyl-ethanolamine, to the hydrophilic polymer, monomethoxypoly(ethylene glycol) (MPEG 5000). Such liposomes retain the coating in the presence of plasma, and appear to adsorb plasma components more slowly than liposomes without the polymer, shown using an aqueous two-phase partitioning technique. MPEG-coupled liposomes were cleared from the blood circulation up to 30% more slowly than liposomes without MPEG after intravenous administration to mice, despite the unmodified liposomes being of a composition and size shown previously to favour achievement of maximum half-life. It is suggested that the polymer acts as a surface barrier to plasma factors which otherwise bind to liposomes in the blood and accelerate vesicle removal.

The effect of a single dose of oestradiol on tamoxifen-induced uterine hyperaemia and growth in the rat

1. The effect of oestradiol on tamoxifen - (single doses of each agent) induced responses in the uterus of the mature ovariectomized rat was investigated. The parameters examined were uterine blood flow (measured by the microsphere technique), weight and oestrogen receptor concentrations. 2. Initially the addition of oestradiol to the tamoxifen regimen produced a reduction in uterine blood flow and dry weight which was reflected by a reduction in nuclear oestrogen receptor. However, as the tamoxifen response became more established from 48 h onwards the addition of oestradiol produced an additive effect. These changes were not mirrored by increases in nuclear oestrogen receptor. 3. The results suggest that tamoxifen and oestradiol may, in part, act via different mechanisms; the role of possible mediatory systems such as histamine release and eosinophil migration is discussed. Heterogeneous control systems may also be involved in the early and late uterine response.