Impact of analysis technique on our understanding of the natural history of labour: a simulation study

OBJECTIVE

To evaluate the discrepancy between historical and more recent descriptions of the first stage of labour by testing whether the statistical techniques used recently (repeated-measures polynomial and interval-censored regression) were appropriate for detection of periods of rapid acceleration of cervical dilatation as might occur at the time of transition from a latent to an active phase of labour.

DESIGN AND SETTING

A simulation study using regression techniques.

SAMPLE

We created a simulated data set for 500 000 labours with clearly defined latent and active phases using the parameters described by Friedman. Additionally, we created a data set comprising 500 000 labours with a progressively increasing rate of cervical dilatation.

METHODS

Repeated-measures polynomial regression was used to create summary labour curves based on simulated cervical examinations. Interval-censored regression was used to create centimetre-by-centimetre estimates of rates of cervical dilatation and their 95th centiles.

MAIN OUTCOME MEASURES

Labour summary curves and rates of cervical dilatation.

RESULTS

Repeated-measures polynomial regression did not detect the rapid acceleration in cervical dilatation (i.e. acceleration phase) and overestimated lengths of labour, especially at smaller cervical dilatations. There was a two-fold overestimation in the mean rate of cervical dilatation from 4 to 6 cm. Interval-censored regression overestimated median transit times, at 4- to 5-cm cervical dilatation or when cervical examinations occurred less frequently than 0.5- to 1.5-hourly.

CONCLUSION

Repeated-measures polynomial regression and interval-censored regression should not be routinely used to define labour progress because they do not accurately reflect the underlying data.

TWEETABLE ABSTRACT

Repeated-measures polynomial and interval-censored regression techniques are not appropriate to model first stage of labour.

PL3.6 Targeting GSK-3 activity promotes mitotic catastrophe via centrosome destabilisation and enhances the effect of radiotherapy in glioma models

BACKGROUND

Targeting kinases as regulators of cellular processes that drive cancer progression is a promising approach to improve patient outcome in GBM management. The glycogen synthase kinase 3 (GSK-3) plays a role in cancer progression and is known for its pro-proliferative activity in gliomas. The anti-proliferative and cytotoxic effects of the GSK-3 inhibitor AZD2858 were assessed in relevant in vitro and in vivo glioma models to confirm GSK-3 as a suitable target for improved single agent or combination treatments.

MATERIAL AND METHODS

The immortalised cell line U251 and the patient derived cell lines GBM1 and GBM4 were used in in vitro studies including MTT, clonogenic survival, live cell imaging, immunofluorescence microscopy and flow cytometry to assess the cytotoxic and anti-proliferative effects of AZD2858. Observed anti-proliferative effects were investigated by microarray technology for the identification of target genes with known roles in cell proliferation. Clinical relevance of targeting GSK-3 with the inhibitor either for single agent or combination treatment strategies was determined by subcutaneous and orthotopic in vivo modelling. Whole mount mass spectroscopy was used to confirm drug penetration in orthotopic tumour models.

RESULTS

AZD2858 was cytotoxic at low micromolar concentrations and at sub-micromolar concentrations (0.01 - 1.0 μM) induced mitotic defects in all cell lines examined. Prolonged mitosis, centrosome disruption/duplication and cytokinetic failure leading to cell death featured prominently among the cell lines concomitant with an observed S-phase arrest. No cytotoxic or anti-proliferative effect was observed in normal human astrocytes. Analysis of the RNA microarray screen of AZD2858 treated glioma cells revealed the dysregulation of mitosis-associated genes including ASPM and PRC1, encoding proteins with known roles in cytokinesis. The anti-proliferative and cytotoxic effect of AZD2858 was also confirmed in both subcutaneous and orthotopic in vivo models. In addition, combination treatment with AZD2858 enhanced clinically relevant radiation doses leading to reduced tumour volume and improved survival in orthotopic in vivo models.

CONCLUSION

GSK-3 inhibition with the small molecule inhibitor AZD2858 led to cell death in glioma stem cells preventing normal centrosome function and promoting mitotic failure. Normal human astrocytes were not affected by treatment with the inhibitor at submicromolar concentrations. Drug penetration was observed alongside an enhanced effect of clinical radiotherapy doses in vivo. The reported aberrant centrosomal duplication may be a direct consequence of failed cytokinesis suggesting a role of GSK-3 in regulation of mitosis in glioma. GSK-3 is a promising target for combination treatment with radiation in GBM management and plays a role in mitosis-associated events in glioma biology.

The influence of zero-hours contracts on care worker well-being

Background

Care workers have an important social role which is set to expand with the increasing age of the UK population. However, the majority of care workers are employed on zero-hours contracts.

Aims

Firstly, to investigate the relationship between working conditions and employee outcomes such as engagement and general mental well-being in a sample of UK care workers and management. Secondly, to assess whether the use of zero-hours contracts affects employee well-being.

Methods

A cross-sectional survey of domiciliary care and care home employees, undertaken using the Management Standards Indicator Tool (MSIT), Utrecht Work Engagement Scale (UWES) and General Health Questionnaire (GHQ). T-tests and multivariate linear regression evaluated the differences in scoring between those with differing contractual conditions and job roles, and associations of MSIT scores with UWES and GHQ factors.

Results

Employee understanding of their role and job control were found to be priority areas for improvement in the sample. Similarly, care workers reported greater occupational demands and lower levels of control than management. However, while zero-hours contracts did not significantly influence employee well-being, these employees had greater levels of engagement in their jobs. Despite this, a greater proportion of individuals with zero-hours contracts had scores above accepted mental health cut-offs.

Conclusions

Individual understanding of their role as care workers appears to play an important part in determining engagement and general mental well-being. However, more research is needed on the influence of zero-hours contracts on well-being, particularly in groups with increased likelihood of developing mental health disorders.

Hopanoids play a role in stress tolerance and nutrient storage in the cyanobacterium Nostoc punctiforme

Hopanes are abundant in ancient sedimentary rocks at discrete intervals in Earth history, yet interpreting their significance in the geologic record is complicated by our incomplete knowledge of what their progenitors, hopanoids, do in modern cells. To date, few studies have addressed the breadth of diversity of physiological functions of these lipids and whether those functions are conserved across the hopanoid-producing bacterial phyla. Here, we generated mutants in the filamentous cyanobacterium, Nostoc punctiforme, that are unable to make all hopanoids (shc) or 2-methylhopanoids (hpnP). While the absence of hopanoids impedes growth of vegetative cells at high temperature, the shc mutant grows faster at low temperature. This finding is consistent with hopanoids acting as membrane rigidifiers, a function shared by other hopanoid-producing phyla. Apart from impacting fitness under temperature stress, hopanoids are dispensable for vegetative cells under other stress conditions. However, hopanoids are required for stress tolerance in akinetes, a resting survival cell type. While 2-methylated hopanoids do not appear to contribute to any stress phenotype, total hopanoids and to a lesser extent 2-methylhopanoids were found to promote the formation of cyanophycin granules in akinetes. Finally, although hopanoids support symbiotic interactions between Alphaproteobacteria and plants, they do not appear to facilitate symbiosis between N. punctiforme and the hornwort Anthoceros punctatus. Collectively, these findings support interpreting hopanes as general environmental stress biomarkers. If hopanoid-mediated enhancement of nitrogen-rich storage products turns out to be a conserved phenomenon in other organisms, a better understanding of this relationship may help us parse the enrichment of 2-methylhopanes in the rock record during episodes of disrupted nutrient cycling.

On the optimal control of stationary diffusion processes with inaccessible boundaries and no discounting

Because there are no boundary conditions, extra properties are required in order to identify the correct potential cost function. A solution of the Dynamic Programming equation for one-dimensional processes leads to an optimal solution within a wide class of alternatives (Theorem 1), and is completely optimal if certain conditions are satisfied (Theorem 2). Necessary conditions are also given. Several examples are solved, and some extension to the multidimensional case is shown.

On the optimal control of a deterministic epidemic

A control scheme for the immunisation of susceptibles in the Kermack-McKendrick epidemic model for a closed population is proposed. The bounded control appears linearly in both dynamics and integral cost functionals and any optimal policies are of the “bang-bang” type. The approach uses Dynamic Programming and Pontryagin's Maximum Principle and allows one, for certain values of the cost and removal rates, to apply necessary and sufficient conditions for optimality and show that a one-switch candidate is the optimal control. In the remaining cases we are still able to show that an optimal control, if it exists, has at most one switch.

Examining the family-centred approach to genetic testing and counselling among UK Pakistanis: a community perspective

WHO advice suggests a family-centred approach for managing the elevated risk of recessively inherited disorders in consanguineous communities, whilst emerging policy recommends community engagement as an integral component of genetic service development. This paper explores the feasibility of the family-centred approach in the UK Pakistani origin community. The study took place within a context of debate in the media, professional and lay circles about cousin marriage causing disability in children. Using qualitative methods, a total of six single-sex focus group discussions (n = 50) were conducted in three UK cities with a high settlement of people of Pakistani origin. Tape-recorded transcripts were analysed using framework analysis. Kinship networks within Pakistani origin communities are being sustained and marriage between close blood relatives continues to take place alongside other marriage options. Study participants were critical of what was perceived as a prevalent notion that cousin marriage causes disability in children. They were willing to discuss cousin marriage and disability, share genetic information and engage with genetic issues. A desire for accurate information and a public informed about genetic issues was articulated whilst ineffective communication of genetic risk information undermined professionals in their support role. This study suggests a community that is embracing change, one in which kinship networks are still active and genetic information exchange is taking place. At the community level, these are conditions supportive of the family-centred approach to genetic testing and counselling.

Radiation protection in fixed PET/CT facilities--design and operation

We describe the design of a fixed positron emission tomography (PET)/CT facility and the use of a simulated instantaneous dose-rate plot to visually highlight areas of potentially high radiation exposure. We also illustrate the practical implementation of basic radiation protection principles based on the use of distance and shielding and the minimisation of time spent in hot areas. Staff whole body doses for 4 years are presented with results of an optimisation study analysing the dose arising from the different phases within each study using direct reading dosemeters. The total whole body dose for all staff for each patient fell from 9.5 μSv in the first full year of operation to 4.8 µSv in 2008. The maximum dose to an individual member of staff per patient decreased over the same period from 3.2 to 0.9 µSv. The optimisation study showed that the highest dose was recorded during the injection phase.

Impact of a clonal outbreak of extended-spectrum β-lactamase-producing Klebsiella pneumoniae in the development and evolution of bloodstream infections by K. pneumoniae and Escherichia coli: an 11 year experience in Oxfordshire, UK

OBJECTIVES

The objectives of this study were: (i) to describe an outbreak of multidrug-resistant Klebsiella pneumoniae in our population; (ii) to identify the potential source of this outbreak by examining antibiotic resistance trends in urocultures; (iii) to evaluate the contribution of this outbreak to resistance patterns over time in the two commonest Gram-negative blood culture isolates, namely K. pneumoniae and Escherichia coli; and (iv) to assess risk factors for multidrug resistance and the impact of this resistance on mortality and length of stay.

METHODS

We searched Microbiology and Patient Administration Service databases retrospectively and describe resistance trends in E. coli and K. pneumoniae bloodstream infections (BSIs) in Oxfordshire, UK, over an 11 year period.

RESULTS

An outbreak of a multidrug-resistant, CTX-M-15 extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae clone was identified and shown by multilocus sequence typing to belong to a novel sequence type designated ST490. This was associated with a sporadic change in resistance rates in K. pneumoniae BSIs with rates of multidrug resistance (defined as resistance to three or more antibiotic classes) reaching 40%. A case-control study showed prior antibiotic exposure as a risk factor for infection with this organism. During the same time period, rates of ESBL-producing Klebsiella spp. isolated from urocultures increased from 0.5% to almost 6%. By contrast, the rate of multidrug resistance in E. coli rose more steadily from 0% in 2000 to 10% in 2010.

CONCLUSIONS

Changes in resistance rates may be associated with outbreaks of resistant clones in K. pneumoniae. Changing resistance patterns may affect important health economic issues such as length of stay.

Glioblastoma in a boy with fragile X: an unusual case of neuroprotection

Glioblastomas in children usually occur in the brainstem and are often untreatable and associated with an extremely poor prognosis. Such tumours may however occur in supratentorial locations more typically associated with adult gliomas, where the outcome is more variable, but still poor. This report describes the case of a boy with fragile X who also developed an inoperable midbrain glioblastoma, but who has survived 8 years after diagnosis.

Glioblastoma in a boy with fragile X: an unusual case of neuroprotection

Glioblastomas in children usually occur in the brainstem and are often untreatable and associated with an extremely poor prognosis. Such tumours may however occur in supratentorial locations more typically associated with adult gliomas, where the outcome is more variable, but still poor. We report the case of a boy with fragile X who also developed an inoperable midbrain glioblastoma, but who has survived 8 years after diagnosis.

Phase II trial of carboplatin, weekly paclitaxel, and biweekly bevacizumab in patients with unresectable stage IV melanoma

8560

Background: In patients with metastatic melanoma, the combination of chemotherapy with an agent that specifically targets vascular endothelial growth factor (VEGF) might be able to control tumor growth and progression much more effectively than chemotherapy alone. Methods: A two-stage phase II clinical trial was conducted in patients with unresectable stage IV melanoma to assess the anti-tumor activity and toxicity profile of the combination of paclitaxel (80 mg/m2 IV on days 1, 8 and 15 of a 28-day cycle), carboplatin (AUC = 6 IV on day 1) and bevacizumab (10 mg/kg IV on days 1 and 15). The primary end point of the study was the 8-week progression-free survival rate (PFS). Enrollment to the second stage of the study was opened if 8 or more of the first 20 patients enrolled remained progression-free at 8 weeks. Eligible patients had measurable disease by RECIST criteria, a performance status (PS) of 0–2 and acceptable pre-registration organ function. Exclusion criteria included: brain metastases, significant recent bleeding, uncontrolled hypertension and ongoing anticoagulation. The study opened in February 2006 and completed full study accrual in August 2006. Data from the 20 patients enrolled in the first stage are presented here. Results: Patients (60% male) had a median age of 63 and had a good performance status (85% had PS of 0). M1c disease was present in 45% of patients and 35% had undergone previous chemotherapy for stage IV melanoma (50% prior immunotherapy). Only 6 patients did not complete more than 2 cycles of chemotherapy due to refusal (3), desire for alternative treatment (1) or progression (2). Median follow-up among the 15 patients still alive was 5.5 months (range: 6 weeks - 9 months). The 8-week PFS rate was 70% (14/20). The median time to progression was 163 days. One partial response was observed. There were 3 disease-related deaths at 65, 120 and 190 days post-registration. The most common toxicities were neutropenia (95%; 45% = grade 3), anemia (95%; 15% = grade 3), fatigue (90%; 5% = grade 3), leukopenia (85%; 25% = grade 3), and thrombocytopenia (75%; 5% = grade 3). Conclusions: The combination of paclitaxel, carboplatin and bevacizumab appears to be well tolerated and clinically active in patients with stage IV melanoma.

No significant financial relationships to disclose.

Aerosolized sargramostim for the treatment of metastatic melanoma to the lungs

8565

Background: Previous studies using low-dose (250 ug/dose) aerosolized sargramostim (granulocyte macrophage colony stimulating factor: aero-GM-CSF) for the treatment of metastatic melanoma, revealed anecdotal clinical responses that appeared to correlate with an increase in the number of tumor specific cytotoxic T lymphocytes (CTL) in blood. Herein, we address whether or not further dose escalation of aero-GM-CSF is safe, results in greater increase of melanoma specific CTLs, and affects clinical outcomes. Methods: A 5+5 dose escalation clinical trial was conducted to determine the dose of aero-GM-CSF that would increase in the frequency of peripheral blood melanoma specific CTLs in HLA-A2+ patients with metastatic melanoma to the lungs. Aero-GM-CSF was administered twice daily on days 1–7 and 15–21 of a 28 day cycle at doses of: 500, 750, 1,000, 1,250, 1,500, 1,750, and 2,000 ug per cohort. If at most 2 of 5 patients at a dose level reported a 5-fold increase in CTLs, dose escalation occurred. If not, 5 additional patients were treated at that dose. Dose escalation continued until =2 of 5 patients at a dose level developed severe toxicity, at least 7 of the 10 patients at a dose level reported a 5-fold increase in CTLs, or all dose levels were exhausted. Results: The study accrued 40 patients from August 2002 to July 2006. Four patients cancelled participation prior to treatment. One patient was replaced (500 ug) as he died within 13 days of registration. Among the 35 remaining patients, median age was 58 (23–84), 72% were male, and 72% had a PS=0. Dose escalation was not terminated due to toxicity. Toxicities = grade 3 (at least probably treatment related) included: grade 3 fatigue (1) at 1,000 ug; and grade 3 cough (1), and grade 4 dyspnea (1) at 1,750 ug. At the 2,000 ug dose, most patients (4 of 5) exhibited a greater than 2-fold increase in melanoma specific CTLs. Two of these patients remain on treatment: one with partial response at 14.0 months and the other with stable disease at 6.5 months. A 5-fold increase in tumor specific CTLs was not achieved in any patient. Conclusions: Aero-GM-CSF therapy administered at up to 2,000 ug/dose appears safe and seems to correlate with increased frequencies of tumor specific CTLs in a dose-dependent fashion. Further dose escalation followed by clinical efficacy testing is warranted.

No significant financial relationships to disclose.

Therapeutic starvation and autophagy in prostate cancer: A new paradigm

10530

The metabolic fragility of cancer cells is magnified with the preferential utilization of glycolysis that metabolizes glucose inefficiently rather than oxidative phosphorylation (the “Warburg effect”) and from impaired mechanisms of survival. In fact, one pathway by which cells survive metabolic stress is thought to be autophagy, a catabolic process of organelle digestion, which creates ATP during periods on nutrient limitation. Remarkably, autophagy is often impaired in human prostate cancers, due to either activation of the PI-3 kinase/Akt/mTOR pathway, which normally inhibits autophagy, or through allelic loss of the essential autophagy gene beclin1. This suggests that prostate cancers may be susceptible to metabolic stress that can be exploited therapeutically. Using immortalized mouse epithelial prostate cells, as well as PC-3 and LNCaP cell lines, we demonstrated the cytotoxic effect of 2-deoxyglucose (2DG), as an inhibitor of glycolysis. We found that 2DG induced membrane translocation in cells characteristic of autophagy using a transfected pEGFP-LC3 autophagy marker construct. We then demonstrated that induction of autophagy was dependent on Beclin1 expression in these cell models using Beclin1 siRNA. Based on these data, we initiated a phase I/II clinical trial with 2DG in patients with advanced malignancies and prostate cancer, which is now ongoing. In an effort to develop markers of autophagy for assessment in a clinical trial, we stained a human prostate TMA (>35 patient cores) for Beclin1 by IHC. Beclin1 staining was increased in tumor tissue compared to normal tissue. Staining was imaged and digitized using a 40x volume scan on a high- throughput MedMicro whole slide scanner. The imaged specimens were stored in multi-tiled TIFF format on a redundant array of independent devices (RAID); staining will be analyzed using a color decomposition algorithm and compared to tumor characteristics as we have previously done (Foran DJ et al., IEEE Trans Inf Technol Biomed, 8:89–96, 2004). These data further support the rationale to inhibit metabolism in cancer and the potential importance of autophagy with metabolic approaches to therapy. Further imaging assessment and analysis of markers of autophagy such as Beclin1 are ongoing.

No significant financial relationships to disclose.