Akt-induced endocrine therapy resistance is reversed by inhibition of mTOR signaling

BACKGROUND

Resistance to endocrine therapy is a major impediment in breast cancer therapeutics. The Phosphatidylinositol-3-OH kinase (PI3K)/Protein kinase B (Akt/PKB) kinase signaling pathway has been implicated in altering breast cancer response to multiple therapies. How Akt modulates response is an area of significant clinical relevance.

METHODS

We have used an in vitro model to discern the effects of robust Akt activity on breast cancer cellular response to endocrine therapies.

RESULTS

High levels of Akt activity confer resistance to the aromatase inhibitor Letrozole (Let) and the selective estrogen receptor (ER) down-regulator Fulvestrant (ICI). Akt-induced resistance is not due to failure of these endocrine agents to inhibit estrogen receptor alpha activity. Instead, resistance is characterized by altered cell cycle and apoptotic response. Cotreatment with low concentrations of the mTOR inhibitor RAD-001 and either Let or ICI restores response of the resistant cells to levels observed in the responsive cells treated with either Let or ICI as a single agent.

CONCLUSIONS

Our preliminary findings in experiments with RAD-001 indicate that cotreatment with mTOR inhibitors and either Let or ICI reverses the Akt-mediated resistance and restores responsiveness to antiestrogens. Concurrent ER and mTOR inhibition is therefore an effective strategy to overcome growth factor-induced resistance and bears significant implications for optimal clinical development of these agents in breast cancer treatment.

In vitro abrogation of acquired tamoxifen resistance using histone deacetylase inhibitors

10607

Tamoxifen (TAM) is a highly effective therapy for breast cancer. However, only 60% of estrogen receptor expressing (ER+) breast cancers respond to TAM (40% de-novo resistance). Continuous TAM treatment causes emergence of acquired resistance in these initially- responsive cancers. Strategies that abrogate TAM-resistance are therefore of significant clinical importance. One approach being studied is the use of histone deacetylase (HDAC) inhibitors. These compounds impact tumor biology both at the level of gene transcription and protein stability. In our study, we developed an in vitro model of tamoxifen resistance to test the efficacy of a hydroxamic acid derivative, Trichostatin A (TSA) at modulating breast cancer cell growth both in TAM responsive as well as TAM resistant cells. Forty-eight MCF-7 breast cancer single-cell colonies were isolated from a heterogeneous population, with 16 of the 48 (33%) surviving 4 months of continual growth in charcoal-stripped media with 10-7 M tamoxifen. ER expression was lost in 9 (56%) and HER-2 expression was acquired in 7 (44%) of the 16 resistant clones. The ER-negative cells demonstrated a concomitant increase in p-Rb, p21 and p27 levels, as well as significant increase in activation of both the PI3K and MAP kinase pathways. These results suggest that alteration of parent cell phenotype is an adaptive event at the transcriptional level, and is a significant mechanism for mediating TAM resistance. Inhibition of growth, by TSA, was studied in both the ER+ and ER- cells, with and without cotreatment with TAM. Cotreatment with TSA effectively blocked the emergence of resistance and prolonged the duration of response to TAM. The molecular mechanisms mediating this enhanced response were studied and focused on the effects of TSA on ER and HER-2 activity and expression. Our results indicate that short term exposure to TSA induces suppression of ER gene transcription, as well as targets ER for protein degradation where as long term exposure shows paradoxical effects at the genomic level. The effects of TSA on acquired HER-2 expression are being studied. These data have important clinical ramifications for the clinical development of HDAC inhibitors for the treatment of breast cancer patients.

No significant financial relationships to disclose.

61. GP PERSPECTIVES ON PARTNER NOTIFICATION FOR CHLAMYDIA

As part of a larger, combined qualitative-quantitative study of partner notification, 40 semi-structured in-depth telephone interviews were conducted with General Practitioners (GPs), from Victoria, ACT and Queensland, who had diagnosed at least one case of chlamydia in the last year. Rural doctors and those who had experience working with Aboriginal patients were over-sampled to ensure their views were represented in the study. The interviews explored GPs' current practices with regard to partner notification for chlamydia, barriers they perceived to partner notification for chlamydia in the general practice setting and what resources/incentives they felt would improve partner notification for chlamydia. The GPs in our study primarily ask the index patient to carry out partner notification themselves. It was relatively rare for GPs to have experience of notifying partners on the patient's behalf. Half of the GPs report that they only encourage notification of the patient's current/immediate past partners. There was considerable confusion amongst the GPs interviewed as to the role of government partner notification officers. Many thought that support from a government agency would allow partner notification to occur more effectively. Some were under the impression that this process is automatically activated when they 'notify' that they have diagnosed someone with chlamydia. Some of the main barriers perceived include confusion about issues of privacy and confidentiality with regard to partner notification and the sense that there is a lack of clarity as to what is expected of them in terms of partner notification for chlamydia. Most GPs feel that access to decision support tools and clear guidelines would be helpful. Financial incentives for doing partner notification were seen as particularly important to fund allied health workers' time rather than to pay GPs themselves e.g. for practice nurses and Aboriginal health workers. GPs were enthusiastic about computer based resources to aid in partner notification

Design of trials with dying patients: a feasibility study of cluster randomisation versus randomised consent

There is little rigorous evidence to underpin clinical guidelines for palliative care. However, research in palliative care is difficult, especially with dying patients. Consent is a major issue, since staff do not wish to invite dying patients to participate in trials. We, therefore, conducted a feasibility study in two units within the North West Wales NHS Trust. We explored two novel approaches to research in palliative care -cluster randomisation and randomised consent. All patients admitted to the two units during the study were asked for permission to use their data for research. We allocated the two units, at random, to use cluster randomisation or randomised consent for three months, and then to crossover to the other design. Of 24 patients dying during cluster-randomised phases, 13 gave consent on admission to use their data and were, thus, eligible to enter the trial; however, defined eligibility criteria reduced these to six active participants. Of 29 patients dying during randomised consent phases, seven gave consent on admission to use their data; although two were eligible for randomisation, neither entered the trial. We judge that cluster randomisation is the more effective design for research with dying patients. Computer simulation, based on data from 1500 dying patients on the Welsh Integrated Care Pathway, shows that crossover cluster trials need much smaller samples than simple cluster trials. Furthermore, this study has shown that crossover cluster trials are entirely feasible. We recommend a 'definitive' trial to test the crossover design more widely.

Clinical management of casualties exposed to lung damaging agents: a critical review

There is no specific antidote for the treatment of casualties exposed to chlorine, phosgene, or mustards; therefore, management is largely supportive. Corticosteroid treatment has been given to casualties accidentally exposed to chlorine. Clinical data on efficacy are inconclusive as the numbers given steroids have been small and the indications for administration unclear. There have been no clinical controlled studies. There is a stronger evidence base from animal studies, particularly from porcine and rodent models. Lung injury induced by phosgene and mustard appears to be mediated by glutathione depletion, lipid peroxidation, free radical generation, and subsequent cellular toxicity. There is limited evidence to suggest that repletion of glutathione reduces and/or prevents lung damage by these agents. This may provide an opportunity for therapeutic intervention.

Improving the management and referral of patients with transient ischaemic attacks: a change strategy for a health community

PROBLEM

Rapid referral and management of patients with transient ischaemic attacks is a key component in the national strategy for stroke prevention. However, patients with transient ischaemic attacks are poorly identified and undertreated.

DESIGN AND SETTING

Before and after evaluation of quality improvement programme with controlled comparison in three primary care trusts reflecting diverse populations and organisational structures in an urban district in the North of England.

KEY MEASURES FOR IMPROVEMENT

The proportion of patients receiving antiplatelet drugs and safe driving advice on referral to a specialty clinic, and the numbers of referrals, adjusted for age, to the specialist clinic before and after the improvement programme.

STRATEGIES FOR CHANGE

Interviews with patient and professionals to identify gaps and barriers to good practice; development of evidence based guidelines for the management of patients with transient ischaemic attacks; interactive multidisciplinary workshops for each primary care trust with feedback of individual audit results of referral practice; outreach visits to teams who were unable to attend the workshops; referral templates and desktop summaries to provide reminders of the guidelines to clinicians; incorporation of standards into professional contracts.

EFFECTS OF CHANGE

A significant improvement occurred in identification and referral of patients with transient ischaemic attacks to specialist clinics, with a 41% increase in referrals from trained practices compared with control practices. There were also significant improvements in the early treatment and safety advice provided to patients before referral.

LESSONS LEARNT

A strategic approach to effective quality improvement across a diverse health community is feasible and achievable. Careful planning with patient and professional involvement to develop a tailored and multifaceted quality improvement programme to implement evidence based practice can work in very different primary care settings. Key components of the effectiveness of the model include contextual analysis, strong professional support, clear recommendations based on robust evidence, simplicity of adoption, good communication, and use of established networks and opinion leaders.

Deficits in the mid-brain raphe nuclei and striatum of the AS/AGU rat, a protein kinase C-γ mutant

The AS/AGU rat carries a recessive mutation (agu) in the gene coding for the gamma isoform of protein kinase C. The rat is characterized by disordered locomotion and progressive dysfunction of the nigrostriatal dopaminergic (DA) system. This dysfunction begins with a failure to release DA within the striatum and culminates in cell loss within the substantia nigra pars compacta. The present study examines another midbrain aminergic system with input to the basal ganglia, the serotonergic (5-HT) raphe-striatal system originating in the dorsal raphe nucleus. By 3 months after birth, there is a very substantial reduction in the extracellular levels of 5-HT in the dorsal caudate-putamen of the mutants compared with controls (c. 70%). This is accompanied by a proportional increase in the levels of the 5-HT metabolite 5-hydroxyindole acetic acid (5-HIAA). At a later age, there are reductions in whole tissue 5-HT (and increases in 5-HIAA) in both the striatum and the region containing the dorsal raphe nucleus, as well as numbers of 5-HT-immunoreactive cells in the dorsal raphe nucleus. The median raphe appears to be unaffected. The results are seen in terms of an initial dysfunction in transmitter release leading to cell death, perhaps through the formation of free radicals or neurotoxins.

Doppler ultrasound and clinical findings in patients with acute ischemic stroke treated with intravenous thrombolysis

The aim of this study was to assess cerebral hemodynamics in patients with acute ischemic stroke undergoing thrombolytic therapy and to assess the relationship between cerebral hemodynamics and outcome. Forty-one unselected patients admitted to hospital within 3 h received intravenous thrombolytic therapy and were examined by extracranial and transcranial Doppler ultrasound examinations. Their strokes were clinically graded with the National Institute of Health Stroke Scale. Outcome after 3 months was graded with the modified Rankin Scale. Amongst the 27 patients who had an additional ultrasound examination 24 h after treatment, favorable outcome was significantly more common amongst patients with recanalization than amongst those without (P < 0.004). Thirteen patients with middle cerebral artery occlusions were continuously monitored during thrombolysis and frequently up to 5 h after start of thrombolysis. Early recanalization occurred in nine (69%), at a median delay of 178 min (range 140-287) after stroke onset. All of these nine patients had a favorable outcome. Recanalization within 24 h was associated with favorable outcome. Subgroup analysis suggests that this effect is mostly related to early recanalization within the first 5 h after stroke. Transcranial Doppler may therefore help to identify those patients most probably to benefit from thrombolysis, especially in those patients with a higher potential risk of complications.

Bacterial resistance to silver in wound care

Ionic silver exhibits antimicrobial activity against a broad range of micro-organisms. As a consequence, silver is included in many commercially available healthcare products. The use of silver is increasing rapidly in the field of wound care, and a wide variety of silver-containing dressings are now commonplace (e.g. Hydrofiber dressing, polyurethane foams and gauzes). However, concerns associated with the overuse of silver and the consequent emergence of bacterial resistance are being raised. The current understanding of the biochemical and molecular basis behind silver resistance has been documented since 1998. Despite the sporadic evidence of bacterial resistance to silver, there have been very few studies undertaken and documented to ascertain its prevalence. The risks of antibacterial resistance developing from the use of biocides may well have been overstated. It is proposed that hygiene should be emphasized and targeted towards those applications that have demonstrable benefits in wound care. It is the purpose of this review to assess the likelihood of widespread resistance to silver and the potential for silver to induce cross-resistance to antibiotics, in light of its increasing usage within the healthcare setting.

Short report: encouraging GPs to complete postal questionnaires--one big prize or many small prizes? A randomized controlled trial

BACKGROUND

Low response rates to surveys are a problem in general practice. There is evidence that offering GPs incentives improves response rates to postal questionnaires. However, there is less evidence about the most effective form of incentive.

OBJECTIVE

Our trial aimed to maximize response to a postal questionnaire and to test the most effective form of incentive.

METHODS

The study involved a randomized controlled trial of a postal survey

RESULTS

The incentive of a lottery for six bottles of champagne generated a response rate of 79%. Furthermore, one chance of six bottles generated 9% more responses than six chances of one bottle.

CONCLUSIONS

This study has established that, among incentives for postal questionnaires, one big prize improves the yield more than many small prizes despite the lower odds of winning. It has also confirmed that offering a modest incentive to GPs generates good response rates for postal questionnaires.

Evaluating children's rehabilitation services: an application of a programme logic model

OBJECTIVES

To apply a programme logic model to evaluate the effectiveness of a new therapy service for children with special needs who were in transition from pre-school to kindergarten.

SETTING

A children's outpatient rehabilitation centre in Ontario, Canada.

MAIN OUTCOMES

The short-term outcomes included parents' perceptions of the transition process itself and the information they required, the children's skill development for the transition to kindergarten, and parents' perceptions of services and satisfaction with resources.

METHODS

A combination of quantitative methods [Goal Attainment Scaling (GAS), Measure of Processes of Care (MPOC), Client Satisfaction Questionnaire (CSQ)] and qualitative interviews were used to evaluate both the process ('Outputs') and outcomes ('Short-term objectives') of the new therapy service.

RESULTS

The children involved in the evaluation met or exceeded goals that were set by therapists and parents. Parents' perceptions of, and satisfaction with, the new service were higher than the provincial average. Qualitative data from interviews with parents and service providers supported the findings from standardized measures, and provided suggestions for future service delivery.

CONCLUSIONS

The programme logic model provided researchers and service providers a collaborative and systematic approach to conducting programme evaluation in a relatively short-time frame. It appears to be a useful option for evaluation of other children's services.

Eosinophil activation and cysteinyl leukotriene production in infants with respiratory syncytial virus bronchiolitis

BACKGROUND

It has been suggested that acute infantile bronchiolitis associated with respiratory syncytial virus (RSV) may share some pathogenic features with atopic asthma in that virus-specific IgE is produced and cysteinyl leukotrienes (cLTs) and eosinophil cationic protein (ECP) have been detected in airway secretions. ECP is a specific marker of eosinophil activation although leukotrienes can be released from a variety of cells including mast cells, eosinophils and monocytes.

OBJECTIVE

To test the association between eosinophil activation and cysteinyl leukotriene production in the upper airway secretions of infants with RSV positive (RSV+ve) bronchiolitis.

METHODS

Nasal lavage samples were performed in 78 infants (0.0-11.5 months) admitted to hospital with RSV+ve bronchiolitis soon after admission (0-48 h). Leukotriene C4 (LTC4) was assayed by enzyme immunoassay (EIA) and eosinophil cationic protein (ECP) by fluoroimmunoassay (FIA).

RESULTS

LTC4 was detectable in 51 and ECP in 57 of 78 samples with a significant positive relationship between LTC4 and ECP (r=0.557, P<0.001).

CONCLUSION

In the majority of our subjects with RSV+ve bronchiolitis ECP and LTC4 were detectable in upper airway secretions and were significantly associated with each other. In this clinical setting much of the detected LTC4 within upper airway secretions is likely to originate from the eosinophil, an observation that may have implications for clinical management and for delineation of the underlying mechanisms associated with this illness.

The formation of AFB1-macromolecular adducts in rats and humans at dietary levels of exposure

The levels of aflatoxin B(1)-DNA and aflatoxin B(1)-albumin adducts were investigated by accelerator mass spectrometry (AMS) in humans and rats following exposure to a known, dietary relevant amount of carbon-14 labeled aflatoxin B(1) ([(14)C]AFB(1)). The aims of the study were to: (a) investigate the dose-dependent formation of DNA and protein adducts at very low doses of AFB(1) (0.16 ng/kg-12.3 microg/kg) in the rat; (b) measure the levels of AFB(1)-albumin and AFB(1)-DNA adducts at known, relevant exposures in humans (c) study rat to human extrapolations of AFB(1)-albumin and DNA adduct levels. The results in the rat showed that both AFB(1)-albumin adduct and AFB(1)-DNA adduct formation were linear over this wide dose range. The order of adduct formation within the tissues studied was liver>kidney>colon>lung=spleen. Consenting volunteers received 1 microg ( approximately 15 ng/kg) of [(14)C]AFB(1) in a capsule approximately approximately 3.5-7 h prior to undergoing colon surgery. The mean level of human AFB(1)-albumin adducts was 38.8+/-19.55 pg [(14)C]AFB(1)/mg albumin/microg AFB(1)/kg body weight (b.w.), which was not statistically different to the equivalent dose in the rat (15 ng/kg) 42.29+/-7.13 pg [(14)C]AFB(1)/mg albumin/microg AFB(1)/kg b.w. There was evidence to suggest the formation of AFB(1)-DNA adducts in the human colon at very low doses. Comparison of the linear regressions of hepatic AFB(1)-DNA adduct and AFB(1)-albumin adduct levels in rat found them to be statistically similar suggesting that the level of AFB(1)-albumin adducts are useful biomarkers for AFB(1) dosimetry and may reflect the DNA adduct levels in the target tissue. [(14)C]AFB(1)-DNA and [(14)C]AFB(1)-albumin adducts were hydrolysed and analysed by HPLC to confirm that the [(14)C] measured by AMS was derived from the expected [(14)C]AFB(1) adducts.

Neurophysiological tests and neuroimaging procedures in non-acute headache: guidelines and recommendations

The use of instrumental examinations in headache patients varies widely. In order to evaluate their usefulness, the most common instrumental procedures were evaluated, on the basis of evidence from the literature, by an EFNS Task Force (TF) on neurophysiological tests and imaging procedures in non-acute headache patients. The conclusions of the TF regarding each technique are expressed in the following guidelines for clinical use. 1 Interictal electroencephalography (EEG) is not routinely indicated in the diagnostic evaluation of headache patients. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic and basilar migraine. 2 Recording of evoked potentials is not recommended for the diagnosis of headache disorders. 3 There is no evidence to justify the recommendation of autonomic tests for the routine clinical examination of headache patients. 4 Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pressure algometry and electromyography (EMG) cannot be recommended as clinical diagnostic tests. 5 In adult and paediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological signs or symptoms, the routine use of neuroimaging is not warranted. In patients with atypical headache patterns, a history of seizures and/or focal neurological signs or symptoms, magnetic resonance imaging (MRI) may be indicated. 6 If attacks can be fully accounted for by the standard headache classification [International Headache Society (IHS)], a positron emission tomography (PET) or single-photon emission computerized tomography (SPECT) and scan will generally be of no further diagnostic value. 7 Nuclear medicine examinations of the cerebral circulation and metabolism can be carried out in subgroups of headache patients for diagnosis and evaluation of complications, when patients experience unusually severe attacks, or when the quality or severity of attacks has changed. 8 Transcranial Doppler examination is not helpful in headache diagnosis. Although many of the examinations described are of little or no value in the clinical setting, most of the tools have a vast potential for further exploring the pathophysiology of headaches and the effects of pharmacological treatment.

Frequency and determinants of formal respite service use among caregivers of children with cerebral palsy in Ontario

OBJECTIVE

To describe the use of formal respite services among caregivers of children with cerebral palsy in Ontario and discuss the factors that may contribute to respite use and non-use.

METHODS

A total of 468 caregivers were interviewed about their experience with formal respite services. Interviews were part of a larger cross-sectional study on caregiver health. Caregivers were asked about their knowledge of formal respite services; their use of formal respite services in the past year; financial implications relating to formal respite use; perceived barriers to formal respite service use; and reasons for not using formal respite services (if applicable).

RESULTS

Nearly half (46%) of caregivers in the sample reported using respite services in the past year. Most of the caregivers who used respite services used more than one source of respite, had services provided in their home, often for less than 1 day, and reported using them more than six times. The most commonly cited reason for using formal respite services was for a planned break. Many factors influenced caregivers' use of formal respite services. Caregivers who had a child with a lower level of function, with multiple additional conditions, or who was male, were more likely to use formal respite services. Although over 90% of caregivers indicated that respite use is beneficial for both their family and child, over 60% reported facing many barriers while attempting to access respite services.

CONCLUSION

Results from this cross-sectional study indicate that caregivers who used respite services used them frequently for breaks from caregiving. Caregivers described facing many barriers while attempting to access respite services therefore to improve caregiver's experience with respite services, strategies are suggested.

Economic costs of the foot and mouth disease outbreak in the United Kingdom in 2001

The authors present estimates of the economic costs to agriculture and industries affected by tourism of the outbreak of foot and mouth disease (FMD) in the United Kingdom (UK) in 2001. The losses to agriculture and the food chain amount to about Pound Sterling3.1 billion. The majority of the costs to agriculture have been met by the Government through compensation for slaughter and disposal as well as clean-up costs. Nonetheless, agricultural producers will have suffered losses, estimated at Pound Sterling355 million, which represents about 20% of the estimated total income from farming in 2001. Based on data from surveys of tourism, businesses directly affected by tourist expenditure are estimated to have lost a similar total amount (between Pound Sterling2.7 and Pound Sterling3.2 billion) as a result of reduced numbers of people visiting the countryside. The industries which supply agriculture, the food industries and tourist-related businesses will also have suffered losses. However, the overall costs to the UK economy are substantially less than the sum of these components, as much of the expenditure by tourists was not lost, but merely displaced to other sectors of the economy. Overall, the net effect of FMD is estimated to have reduced the gross domestic product in the UK by less than 0.2% in 2001.

William Hunter's Gravid Uterus: the specimens and plates

William Hunter's collection of anatomical specimens of the pregnant uterus forms one of the finest displays in the Anatomy Museum at the University of Glasgow. We were interested to know which specimens in the Museum matched the plates in Hunter's The Anatomy of the Human Gravid Uterus Exhibited in Figures (1774). In our investigation we were greatly assisted by Teacher's Catalogue of the Anatomical and Pathological Preparations of Dr William Hunter (1900). Thirteen specimens in the Museum and one from the pathological collection at the Royal Infirmary are represented in Hunter's book. The specimens can be recognized in 25 of its illustrations. A further three specimens may correspond to figures but we could not prove this. With one possible exception, all the specimens matching plates noted in Teacher's catalogue remain in the Museum and one believed missing in Marshall's (1970) revision of the catalogue has been found.

The CFTR-mediated protein secretion defect: pharmacological correction

The cystic fibrosis transmembrane conductance regulator (CFTR) mediates secretion of mucins and serous proteins. The aim was to correct pharmacologically the CFTR defect in protein secretion in airway gland cells and so to correct the viscous mucous secretions in cystic fibrosis (CF) airways and lungs. The strategies tested included direct activation of CFTR, bypass of CFTR-mediated protein secretion and movement of the mutated form of CFTR (DeltaF(508)-CFTR) to the cell membrane. Compounds related to 3-isobutyl-1-methylxanthine (IBMX), including a selective type-IV phosphodiesterase inhibitor and the adenosine receptor antagonists 8-cyclopentyltheophylline (CPT) and 8-cyclopentyl-1,3-dipropylxanthine (CPX), corrected the defective beta-adrenergic stimulation of mucin secretion in CFTR antibody-inhibited submandibular gland cells. CPT also corrected lactoferrin secretion in DeltaF(508)/DeltaF(508)-CFTR nasal gland cells. The data suggest that correction of CFTR protein secretion activity is not mediated by excessive increase in cyclic AMP, involves direct interaction with CFTR but does not require increase in CFTR Cl(-) channel activity. Regulated glycoprotein secretion was characterised in the airway gland cell line Calu-3 to investigate whether a CFTR bypass is present. Studies of DeltaF(508)-CFTR trafficking using confocal imaging showed that some DeltaF(508)-CFTR colocalised with the apical membrane protein CD59; however a large amount was mislocalised within the cell. The results showing pharmacological correction of the defective CFTR-mediated protein secretion afford promise for the development of a rational drug therapy for CF patients.