Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Cost-effectiveness of insulin degludec compared with insulin glargine for patients with type 2 diabetes treated with basal insulin - from the UK health care cost perspective

AIMS

The aim of this analysis was to evaluate the cost-effectiveness of insulin degludec (IDeg) versus insulin glargine (IGlar) in adults with type 2 diabetes mellitus (T2DM) who are considered appropriate for treatment with a basal insulin analogue, using a short-term economic model.

METHODS

Meta-analysis data from three phase III clinical studies were used to populate a simple and transparent short-term model. The costs and effects of treatment with IDeg versus IGlar were calculated over a 12-month period. The analysis was conducted from the perspective of the UK National Health Service. Sensitivity analyses were conducted to assess the degree of uncertainty surrounding the results.

RESULTS

IDeg is a cost-effective treatment option versus IGlar in patients with T2DM using basal insulin. Base case incremental cost-effectiveness ratios (ICERs) were estimated at £15,795 per quality-adjusted life-year (QALY) and £13,078 per QALY, which are below commonly accepted thresholds for cost-effectiveness. Sensitivity analyses demonstrated that hypoglycaemia event rates had an important effect on the results. With higher event rates for non-severe hypoglycaemia IDeg was less costly and more effective than IGlar (dominant). Conversely, using lower event rates for severe hypoglycaemia generated higher ICERs. Using hypoglycaemia rates from a subgroup of patients who experienced ≥1 hypoglycaemic event per year IDeg was highly cost-effective versus IGlar; with estimated ICERS of £4887 and £2625 per QALY.

CONCLUSIONS

This short-term modelling approach allows the economic evaluation of newer insulin analogues when advanced long-term modelling based on HbA1c differences is inappropriate. For patients with T2DM who are considered appropriate for treatment with a basal insulin analogue, IDeg is a cost-effective treatment option compared with IGlar and offers additional benefits to subgroups of patients, such as those suffering from recurrent hypoglycaemia.

Influence of cold walls on PET image quantification and volume segmentation: a phantom study

PURPOSE

Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These "cold" walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in errors in the estimation of standardized uptake values. Numerous papers suggest that this is an issue for phantom work simulating tumor tissue, quality control, and calibration work. This study aims to investigate the influence of the cold plastic wall thickness on the quantification of 18F-fluorodeoxyglucose on the image activity recovery and on the performance of advanced automatic segmentation algorithms for the delineation of active regions delimited by plastic walls.

METHODS

A commercial set of six spheres of different diameters was replicated using a manufacturing technique which achieves a reduction in plastic walls thickness of up to 90%, while keeping the same internal volume. Both sets of thin- and thick-wall inserts were imaged simultaneously in a custom phantom for six different tumor-to-background ratios. Intensity values were compared in terms of mean and maximum standardized uptake values (SUVs) in the spheres and mean SUV of the hottest 1 ml region (SUVmax, SUVmean, and SUVpeak). The recovery coefficient (RC) was also derived for each sphere. The results were compared against the values predicted by a theoretical model of the PET-intensity profiles for the same tumor-to-background ratios (TBRs), sphere sizes, and wall thicknesses. In addition, ten automatic segmentation methods, written in house, were applied to both thin- and thick-wall inserts. The contours obtained were compared to computed tomography derived gold standard ("ground truth"), using five different accuracy metrics.

RESULTS

The authors' results showed that thin-wall inserts achieved significantly higher SUVmean, SUVmax, and RC values (up to 25%, 16%, and 25% higher, respectively) compared to thick-wall inserts, which was in agreement with the theory. This effect decreased with increasing sphere size and TBR, and resulted in substantial (>5%) differences between thin- and thick-wall inserts for spheres up to 30 mm diameter and TBR up to 4. Thinner plastic walls were also shown to significantly improve the delineation accuracy for the majority of the segmentation methods tested, by increasing the proportion of lesion voxels detected, although the errors in image quantification remained non-negligible.

CONCLUSIONS

This study quantified the significant effect of a 90% reduction in the thickness of insert walls on SUV quantification and PET-based boundary detection. Mean SUVs inside the inserts and recovery coefficients were particularly affected by the presence of thick cold walls, as predicted by a theoretical approach. The accuracy of some delineation algorithms was also significantly improved by the introduction of thin wall inserts instead of thick wall inserts. This study demonstrates the risk of errors deriving from the use of cold wall inserts to assess and compare the performance of PET segmentation methods.

Severe hypoglycaemia in type 1 diabetes mellitus: underlying drivers and potential strategies for successful prevention

Hypoglycaemia remains an over-riding factor limiting optimal glycaemic control in type 1 diabetes. Severe hypoglycaemia is prevalent in almost half of those with long-duration diabetes and is one of the most feared diabetes-related complications. In this review, we present an overview of the increasing body of literature seeking to elucidate the underlying pathophysiology of severe hypoglycaemia and the limited evidence behind the strategies employed to prevent episodes. Drivers of severe hypoglycaemia including impaired counter-regulation, hypoglycaemia-associated autonomic failure, psychosocial and behavioural factors and neuroimaging correlates are discussed. Treatment strategies encompassing structured education, insulin analogue regimens, continuous subcutaneous insulin infusion pumps, continuous glucose sensing and beta-cell replacement therapies have been employed, yet there is little randomized controlled trial evidence demonstrating effectiveness of new technologies in reducing severe hypoglycaemia. Optimally designed interventional trials evaluating these existing technologies and using modern methods of teaching patients flexible insulin use within structured education programmes with the specific goal of preventing severe hypoglycaemia are required. Individuals at high risk need to be monitored with meticulous collection of data on awareness, as well as frequency and severity of all hypoglycaemic episodes.

[First stage in identifying traumatic profil inpatients hospitalised in psychiatry in Martinique]

The population hospitalised in psychiatry seems more exposed to traumatic events than the French general population, with particularly more sexual aggressions. The aim of this study is to describe the population hospitalised in psychiatry and more precisely the traumatic history of these patients, their comorbidities (mental diseases and addictions), and socio economical level. This descriptive, cross sectional and retrospective study took place in the Crisis Center in the University Hospital in Martinique (French West Indies), from February to July 2013. A socio-demographic information, the Mini International Neuropsychiatric Interview 5.0, the Trauma History Questionnaire and the Impact Events Scale-Revised were realised with 49 of the 143 patients admitted during this period (34.3%). In this population, we found a mean of 6.5 (standart-deviation=4.2) different types of traumatic event, with 38.8% patients reporting a natural disaster, and 38.8% declaring at least one sexual aggression. In the 25 patients suffering from post-traumatic stress disorder, 66.7% underwent a sexual aggression, significatively during childhood (before 10 years old, P=0.01), and during adolescence (between 10 to 18 years old, P=0.01). These results underline the importance of a systematic screening of the traumatic profile: the characteristics of the traumatic events and its clinical impact.

Loss in long-storage-time optical cavities

Long-storage-time Fabry-Perot cavities are a core component of many precision measurement experiments. Optical loss in such cavities is a critical parameter in determining their performance; however, it is very difficult to determine a priori from independent characterisation of the individual cavity mirrors. Here, we summarise three techniques for directly measuring this loss in situ and apply them to a high-finesse, near-concentric, 2 m system. Through small modifications of the cavity's length, we explore optical loss as a function of beam spot size over the 1-3 mm range. In this regime we find that optical loss is relatively constant at around 5 ppm per mirror and shows greater dependence on the positions of the beam spots on the cavity optics than on their size. These results have immediate consequences for the application of squeezed light to advanced gravitational-wave interferometers.

Étude descriptive des comorbidités somatiques et psychiatriques dans une population hospitalisée en psychiatrie en Martinique. Étude préliminaire

Introduction

Les patients souffrant de maladies mentales meurent en moyenne 25 ans plus tôt que la population générale. Les causes de mortalité sont notamment liées aux maladies cardiovasculaires, en lien avec le syndrome métabolique. Peu de littérature explore les comorbidités somatiques et psychiatriques dans les Antilles françaises. L’objectif principal de cette étude préliminaire est de décrire au centre de crise du CHU de Martinique la population hospitalisée sur le plan somatique (syndrome métabolique) et sur le plan des comorbidités psychiatriques (dont les comorbidités psychotraumatiques).

Methods

Dans cette étude prospective où 49 patients ont été inclus de façon aléatoire entre février et juillet 2013, nous avons évalué les éléments suivants : syndrome métabolique, MINI, THQ, IESR.

Résultats

Cette population est âgée de 44 ans en moyenne. Le syndrome métabolique est retrouvé chez 33 % de la population. Les comorbidités psychiatriques : 75 % de dépression, 57 % de risque suicidaire moyen à élevé. Au niveau des évènements traumatisants (médiane du nombre d’évènements traumatisants à 6) : 45 % déclarent avoir subi des agressions sexuelles, 43 % des catastrophes naturelles. Le score total de l’IESR a un score médian à 37,5.

Conclusion

Ces résultats rappellent la nécessité de systématiser la recherche du syndrome métabolique et des évènements traumatiques en hospitalisation en psychiatrie.

Squeezed quadrature fluctuations in a gravitational wave detector using squeezed light

Squeezed states of light are an important tool for optical measurements below the shot noise limit and for optical realizations of quantum information systems. Recently, squeezed vacuum states were deployed to enhance the shot noise limited performance of gravitational wave detectors. In most practical implementations of squeezing enhancement, relative fluctuations between the squeezed quadrature angle and the measured quadrature (sometimes called squeezing angle jitter or phase noise) are one limit to the noise reduction that can be achieved. We present calculations of several effects that lead to quadrature fluctuations, and use these estimates to account for the observed quadrature fluctuations in a LIGO gravitational wave detector. We discuss the implications of this work for quantum enhanced advanced detectors and even more sensitive third generation detectors.

Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes

BACKGROUND

Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients.

METHODS

In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years.

RESULTS

The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51).

CONCLUSIONS

An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).

Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes

BACKGROUND

Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients.

METHODS

In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years.

RESULTS

The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51).

CONCLUSIONS

An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).

A comparison of health-related quality of life (health utility) between insulin degludec and insulin glargine: a meta-analysis of phase 3 trials

AIM

To evaluate health-related quality of life (health utility) scores in patients with diabetes receiving insulin degludec (IDeg) or insulin glargine (IGlar).

METHODS

Patient-level data from six, randomized, controlled, open-label, multicentre, confirmatory, treat-to-target trials of 26- or 52 weeks' duration were pooled in this analysis. The Short Form 36 (SF-36) version-2 health questionnaire was completed by patients at baseline and end-of-trial. SF-36 scores for 4001 individual patients were then mapped onto the EuroQol-5D health utility scale, which has a range from -0.59 (a state worse than death) to 1.00 (perfect health).

RESULTS

IDeg treatment exhibited a significant improvement in health status of 0.005 (CI: 0.0006; 0.009) points compared with IGlar (p < 0.024). Gender, region, trial and age also had a significant influence on estimated utility scores as did baseline utility scores, p < 0.05. Prior to the removal of interaction variables a difference of 0.008 points was observed, p < 0.045. Previous insulin treatment did not have an impact on the final outcome.

CONCLUSION

This study shows that IDeg is associated with a modest, but statistically significant, improvement in health utility compared with IGlar in patients with diabetes.

Surgical resection of recurrent colonic cancer

Background

Locoregional recurrence of colonic cancer includes anastomotic recurrence, associated nodal masses, masses that involve the abdominal wall and pelvic masses. The aim of this study was to report the outcome of resection of such recurrences and to provide guidance on the management of this disease.

Methods

Patients were identified from a prospectively maintained database. Data were obtained on demographics, surgical procedure, morbidity, histopathology and outcome. Univariable and multivariable analyses of factors influencing survival were performed using stepwise Cox logistic regression.

Results

Forty-two patients (21 men; median age 61 (range 41–82) years) underwent resection of recurrent colonic cancer between 2003 and 2011. The median interval between resection of the primary and recurrent colonic tumour was 37·5 (interquartile range 7–91) months. The recurrences developed at the previous anastomosis (9 patients), elsewhere within the abdominal cavity or wall (8) and as discrete masses within the pelvic cavity (25). Eighteen of 42 patients underwent resection of hepatic or pulmonary metastases at some stage after resection of the primary tumour. Median survival was 29 months after R0 resection and 26 months after R1 resection of the recurrent tumour (P = 0·226). The survival benefit depended on the location of the recurrence (median survival after resection of recurrent disease: anastomotic 33 months, pelvic 26 months, abdominal 19 months; P = 0·010).

Conclusion

This study described a classification system, management algorithm and prognostic factors for recurrent colonic cancer. The distribution of disease influenced survival. Long-term survival was achieved, including a subset of patients with drop metastases and/or previous metastasectomy.

Linagliptin as add-on therapy for type 2 diabetes - an overview

The pathogenesis of type 2 diabetes (T2D) can result in decreased levels of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which under normal circumstances increase insulin secretion and suppress glucagon release. A new form of drug therapy known as dipeptidyl peptidase 4 (DPP IV) inhibitors has focused on increasing the circulating levels of these "incretin" hormones in order to improve glycemic control in patients with T2D. The DPP IV inhibitors saxagliptin, vildagliptin, linagliptin, alogliptin and sitagliptin function by inhibiting the enzyme DPP IV, which breaks down GLP-1 and GIP, and have had significant success. However, with most DPP IV inhibitors being extensively excreted renally, this is a significant issue, as a large proportion of diabetic patients suffer from renal complications. Linagliptin is a novel DPP IV inhibitor that is excreted primarily by the hepatic route, with little need for dose adjustment in patients with renal impairment. It therefore represents a major advancement in the pharmacotherapy of patients with T2D.

Midcourse correction to a clinical trial when the event rate is underestimated: the Look AHEAD (Action for Health in Diabetes) Study

The Look AHEAD (Action for Health in Diabetes) Study is a long-term clinical trial that aims to determine the cardiovascular disease (CVD) benefits of an intensive lifestyle intervention (ILI) in obese adults with type 2 diabetes. The study was designed to have 90% statistical power to detect an 18% reduction in the CVD event rate in the ILI Group compared to the Diabetes Support and Education (DSE) Group over 10.5 years of follow-up. The original power calculations were based on an expected CVD rate of 3.125% per year in the DSE group; however, a much lower-than-expected rate in the first 2 years of follow-up prompted the Data and Safety Monitoring Board (DSMB) to recommend that the Steering Committee undertake a formal blinded evaluation of these design considerations. The Steering Committee created an Endpoint Working Group (EPWG) that consisted of individuals masked to study data to examine relevant issues. The EPWG considered two primary options: (1) expanding the definition of the primary endpoint and (2) extending follow-up of participants. Ultimately, the EPWG recommended that the Look AHEAD Steering Committee approve both strategies. The DSMB accepted these modifications, rather than recommending that the trial continue with inadequate statistical power. Trialists sometimes need to modify endpoints after launch. This decision should be well justified and should be made by individuals who are fully masked to interim results that could introduce bias. This article describes this process in the Look AHEAD study and places it in the context of recent articles on endpoint modification and recent trials that reported endpoint modification.

The EQUAL study: a European study in chronic kidney disease stage 4 patients

The timing of the start of dialysis in elderly patients is driven by the desire to optimize the quantity and quality of life. Limited data exist on how the level of renal function, and uraemic signs and symptoms can be used to determine when dialysis should be initiated in elderly patients. EQUAL, an international prospective cohort study, aims to address these issues. To this end, it will enroll 3500 patients >65 years of age with CKD of various aetiologies under the care of nephrologists. These patients will be followed until death, discharge from the nephrology clinic to primary care or until the end of the observation period after 4 years of follow-up. At the time of enrollment, patients must have an estimated glomerular filtration rate (eGFR) of 20 mL/min/1.73 m(2) or lower, but should not yet be on dialysis. Standardized data collection will include demographics, lifestyle, comorbidities, uraemic signs and symptoms, nutritional status, medication and routine blood and urine biochemistry. It will also comprise quality of life data, information on decision making including patients preferences and patients satisfaction.

Sci-Sat AM: Brachy - 04: Neutron production around a radiation therapy linac bunker - monte carlo simulations and physical measurements

Photoneutrons are a major component of the equivalent dose in the maze and near the door of linac bunkers. Physical measurements and Monte Carlo (MC) calculations of neutron dose are key for validating bunker design with respect to health regulations. We attempted to use bubble detectors and a ³ He neutron spectrometer to measure neutron equivalent dose and neutron spectra in the maze and near the door of one of our bunkers. We also ran MC simulations with MCNP5 to measure the neutron fluence in the same region. Using a point source of neutrons, a Clinac 1800 linac operating at 10 MV was simulated and the fluence measured at various locations of interest. We describe the challenges faced when measuring dose with bubble detectors in the maze and the complexity of photoneutron spectrometry with linacs operating in pulsed mode. Finally, we report on the development of a userfriendly GUI for shielding calculations based on the NCRP 151 formalism.

An experimental feasibility study on the use of scattering foil free beams for modulated electron radiotherapy

The potential benefit of using scattering foil free beams for delivery of modulated electron radiotherapy is investigated in this work. Removal of the scattering foil from the beamline showed a measured bremsstrahlung tail dose reduction just beyond R(p) by a factor of 12.2, 6.9, 7.4, 7.4 and 8.3 for 6, 9, 12, 16 and 20 MeV beams respectively for 2 × 2 cm(2) fields defined on-axis when compared to the clinical beamline. Monte Carlo simulations were matched to measured data through careful tuning of source parameters and the modification of certain accelerator components beyond the manufacturer's specifications. An accelerator model based on the clinical beamline and one with the scattering foil removed were imported into a Monte Carlo-based treatment planning system (McGill Monte Carlo Treatment Planning). A treatment planning study was conducted on a test phantom consisting of a PTV and two distal organs at risk (OAR) by comparing a plan using the clinical beamline to a plan using a scattering foil free beamline. A DVH comparison revealed that for quasi-identical target coverage, the volume of each OAR receiving a given dose was reduced, thus reducing the dose deposited in healthy tissue.

Weight change in people with type 2 diabetes: secular trends and the impact of alternative antihyperglycaemic drugs

AIM

This study aimed to describe the pattern of weight change in people with type 2 diabetes (T2DM) over time and when using alternative treatment regimens.

METHODS

Data were from routine clinical practice in the UK. The weight trend was determined for each year from 1995 to 2010 for both prevalent and incident cases. Baseline weight was compared to absolute (mean Δ) and relative weights (% Δ) at 6, 12 and 24 months.

RESULTS

Mean, standardized weight in prevalent cases increased from 83.4 to 92.1 kg for males and from 73.5 to 79.9 kg for females between 1995 and 2010 (p < 0.0001). For incident cases, the respective figures were 86.7 to 93.6 kg for males and 76.0 to 80.7 kg for females (p < 0.001). Between baseline and 6, 12 and 24 months, there were significant changes in weight for the majority of the treatment regimens selected for analysis. The largest weight increase at 12 months was for the patients who were prescribed a combination therapy with insulin and a thiazolidinedione, with a median increase of 4.1 kg (95% CI -0.60 to 8.0, p < 0.001). The largest weight decrease at 12 months was for the patients who were prescribed a combination therapy of metformin and exenatide, with a median decrease of -7.0 kg (95% CI -12.0 to -2.0, p < 0.001).

CONCLUSIONS

There was a continual increase in body weight in people with T2DM over time, and considerable differences in the impact on weight using alternative treatment regimens. At the same time, glycaemic control remained relatively unchanged.

Directional limits on persistent gravitational waves using LIGO S5 science data

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.

P5-14-11: Elevated Serum Ferritin Predicts Reduced Progression-Free and Overall Survival in Trastuzumab-Treated Metastatic Breast Cancer

Background: Approximately one-half of HER2−positive breast cancer patients will not respond to first-line trastuzumab-containing therapy. Since trastuzumab is now used in the HER2−positive adjuvant breast cancer setting, trastuzumab resistance will continue to be a vexing clinical problem, and better predictive and prognostic biomarkers are urgently needed.

One potential biomarker is serum ferritin. Although serum ferritin has been used as an indicator of total body iron, a specific functional role has not been proposed thus far other than perhaps recycling iron for erythropoiesis. Increased serum ferritin levels have been reported in breast cancer patients. However, the prevailing paradigm on ferritin at the time of these observations did not encourage speculation on its role or significance and was dismissed as a non-specific parameter for cellular damage. There are now multiple lines of evidence that have challenged this traditional paradigm and suggested ferritin to be a multi-functional factor involved in key cellular and systemic processes including immune regulation, angiogenesis, and iron delivery.

Methods: Pretreatment serum ferritin was measured using an ELISA assay in 66 metastatic breast cancer patients before starting first-line trastuzumab-containing therapy. Serum ferritin was determined using an ELISA from Assaypro, St. Charles, MO. Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method and Cox modeling, with separate analyses as continuous serum ferritin, or as dichotomous categorical groups using the median pretreatment serum ferritin level as a cut off point. To interrogate a functional impact of elevated serum ferritin, we used a cell culture model.

Results: When analyzed as dichotomous categorical groups using the median pretreatment serum ferritin level as a cut off point, the elevated serum ferritin patient cohort had a significantly reduced OS (P&lt;0.0001, median OS 12.73 vs. 69.57 months) and PFS (P=0.004, 8.30 vs. 23.90 months). In the cell culture model, ferritin bound to breast cancer cells promoted proliferation and activated AKT signaling. These novel observations suggest that the iron storage protein ferritin has a signaling role in tumor biology. Since the elevation in serum ferritin is unlikely a consequence of a change in total body iron, we also examined several possible sources for this elevation. Macrophages, but not breast cancer cells, were capable of ferritin secretion.

Conclusions: Elevated serum ferritin predicts reduced PFS and overall survival in metastatic breast cancer patients treated with first-line trastuzumab-containing therapy. The ability of ferritin to activate AKT signaling could underlie the trastuzumab resistance in patients. Therefore, serum ferritin may not only have predictive value as a clinical tool but also has direct functional significance in the treatment response, progression and survival of breast cancer patients.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-11.

Optimal alignment sensing of a readout mode cleaner cavity

Critically coupled resonant optical cavities are often used as mode cleaners in optical systems to improve the signal-to-noise ratio (SNR) of a signal that is encoded as an amplitude modulation of a laser beam. Achieving the best SNR requires maintaining the alignment of the mode cleaner relative to the laser beam on which the signal is encoded. An automatic alignment system that is primarily sensitive to the carrier field component of the beam will not, in general, provide optimal SNR. We present an approach that modifies traditional dither alignment sensing by applying a large amplitude modulation on the signal field, thereby producing error signals that are sensitive to the signal sideband field alignment. When used in conjunction with alignment actuators, this approach can improve the detected SNR; we demonstrate a factor of 3 improvement in the SNR of a kilometer-scale detector of the Laser Interferometer Gravitational-Wave Observatory. This approach can be generalized to other types of alignment sensors.

Using highly variable warfarin dosing to identify patients at risk for adverse events

BACKGROUND

Patients who receive highly variable doses of warfarin may be at risk for poor anticoagulation control and adverse events. However, we lack a system to identify patients with the highest dose variability. Our objectives were to develop a scoring system to identify patients with high dose variability, and to validate this new measure by demonstrating that patients so identified have poor anticoagulation control and higher rates of adverse events (criterion validity).

METHODS

We used a database of over 4, 000 patients who received oral anticoagulation in community practice between 2000-2002. We reviewed the charts of 168 patients with large warfarin dose variation and agreed on 18 risk factor definitions for high dose variability. We identified 109 patients with the highest dose variability (cases), as measured by coefficient of variation (CoV, SD/mean). We matched each case to two controls with low dose variability. Then, we examined all 327 charts, blinded to case/control status, to identify the presence or absence of the 18 risk factors for dose variability. We performed a multivariable analysis to identify independent predictors of high CoV. We also compared anticoagulation control, as measured by percent time in therapeutic range (TTR), and rates of adverse events between groups.

RESULTS

CoV corresponded with other measures of anticoagulation control. TTR was 53% among cases and 79% among controls (p < 0.001). CoV also predicted adverse events. Six cases experienced a major hemorrhage versus 1 control (p < 0.001) and 3 cases had a thromboembolic event versus 0 control patients (p = 0.04). Independent predictors of high dose variability included hospitalization (OR = 21.3), decreased oral intake (OR = 12.2), use of systemic steroids (OR = 6.1), acetaminophen (OR = 4.0) and antibiotics (OR = 2.7; p < 0.05 for all).

CONCLUSION

CoV can be used to identify patients at risk for poor anticoagulation control and adverse events. This new measure has the potential to identify patients at high risk before they suffer adverse events.