176 research outputs found
Algorithm and Complexity for a Network Assortativity Measure
We show that finding a graph realization with the minimum Randi\'c index for
a given degree sequence is solvable in polynomial time by formulating the
problem as a minimum weight perfect b-matching problem. However, the
realization found via this reduction is not guaranteed to be connected.
Approximating the minimum weight b-matching problem subject to a connectivity
constraint is shown to be NP-Hard. For instances in which the optimal solution
to the minimum Randi\'c index problem is not connected, we describe a heuristic
to connect the graph using pairwise edge exchanges that preserves the degree
sequence. In our computational experiments, the heuristic performs well and the
Randi\'c index of the realization after our heuristic is within 3% of the
unconstrained optimal value on average. Although we focus on minimizing the
Randi\'c index, our results extend to maximizing the Randi\'c index as well.
Applications of the Randi\'c index to synchronization of neuronal networks
controlling respiration in mammals and to normalizing cortical thickness
networks in diagnosing individuals with dementia are provided.Comment: Added additional section on application
New Experimental Limit on the Electric Dipole Moment of the Electron in a Paramagnetic Insulator
We report results of an experimental search for the intrinsic Electric Dipole
Moment (EDM) of the electron using a solid-state technique. The experiment
employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a
large magnetic response at low temperatures. The presence of the eEDM would
lead to a small but non-zero magnetization as the GGG sample is subject to a
strong electric field. We search for the resulting Stark-induced magnetization
with a sensitive magnetometer. Recent progress on the suppression of several
sources of background allows the experiment to run free of spurious signals at
the level of the statistical uncertainties. We report our first limit on the
eEDM of 10ecm with 5 days of
data averaging.Comment: 9 pages, 9 figures, Revtex 4.
A Novel Approach for the Discovery of Biomarkers of Radiotherapy Response in Breast Cancer
Radiotherapy (RT) is an important treatment modality for the local control of breast cancer (BC). Unfortunately, not all patients that receive RT will obtain a therapeutic benefit, as cancer cells that either possess intrinsic radioresistance or develop resistance during treatment can reduce its efficacy. For RT treatment regimens to become personalised, there is a need to identify biomarkers that can predict and/or monitor a tumour’s response to radiation. Here we describe a novel method to identify such biomarkers. Liquid chromatography-mass spectrometry (LC-MS) was used on conditioned media (CM) samples from a radiosensitive oestrogen receptor positive (ER+) BC cell line (MCF-7) to identify cancer-secreted biomarkers which reflected a response to radiation. A total of 33 radiation-induced secreted proteins that had higher (up to 12-fold) secretion levels at 24 h post-2 Gy radiation were identified. Secretomic results were combined with whole-transcriptome gene expression experiments, using both radiosensitive and radioresistant cells, to identify a signature related to intrinsic radiosensitivity. Gene expression analysis assessing the levels of the 33 proteins showed that 5 (YBX3, EIF4EBP2, DKK1, GNPNAT1 and TK1) had higher expression levels in the radiosensitive cells compared to their radioresistant derivatives; 3 of these proteins (DKK1, GNPNAT1 and TK1) underwent in-lab and initial clinical validation. Western blot analysis using CM samples from cell lines confirmed a significant increase in the release of each candidate biomarker from radiosensitive cells 24 h after treatment with a 2 Gy dose of radiation; no significant increase in secretion was observed in the radioresistant cells after radiation. Immunohistochemistry showed that higher intracellular protein levels of the biomarkers were associated with greater radiosensitivity. Intracellular levels were further assessed in pre-treatment biopsy tissues from patients diagnosed with ER+ BC that were subsequently treated with breast-conserving surgery and RT. High DKK1 and GNPNAT1 intracellular levels were associated with significantly increased recurrence-free survival times, indicating that these two candidate biomarkers have the potential to predict sensitivity to RT. We suggest that the methods highlighted in this study could be utilised for the identification of biomarkers that may have a potential clinical role in personalising and optimising RT dosing regimens, whilst limiting the administration of RT to patients who are unlikely to benefit
Change in the Use of Fractionation in Radiotherapy Used for Early Breast Cancer at the Start of the COVID-19 Pandemic: A Population-Based Cohort Study of Older Women in England and Wales.
AIMS: Adjuvant radiotherapy is recommended for most patients with early breast cancer (EBC) receiving breast-conserving surgery and those at moderate/high risk of recurrence treated by mastectomy. During the first wave of COVID-19 in England and Wales, there was rapid dissemination of randomised controlled trial-based evidence showing non-inferiority for five-fraction ultra-hypofractionated radiotherapy (HFRT) regimens compared with standard moderate-HFRT, with guidance recommending the use of five-fraction HFRT for eligible patients. We evaluated the uptake of this recommendation in clinical practice as part of the National Audit of Breast Cancer in Older Patients (NABCOP). MATERIALS AND METHODS: Women aged ≥50 years who underwent surgery for EBC from January 2019 to July 2020 were identified from the Rapid Cancer Registration Dataset for England and from Wales Cancer Network data. Radiotherapy details were from linked national Radiotherapy Datasets. Multivariate mixed-effects logistic regression models were used to assess characteristics influential in the use of ultra-HFRT. RESULTS: Among 35 561 women having surgery for EBC, 71% received postoperative radiotherapy. Receipt of 26 Gy in five fractions (26Gy5F) increased from <1% in February 2020 to 70% in April 2020. Regional variation in the use of 26Gy5F during April to July 2020 was similar by age, ranging from 49 to 87% among women aged ≥70 years. Use of 26Gy5F was characterised by no known nodal involvement, no comorbidities and initial breast-conserving surgery. Of those patients receiving radiotherapy to the breast/chest wall, 85% had 26Gy5F; 23% had 26Gy5F if radiotherapy included regional nodes. Among 5139 women receiving postoperative radiotherapy from April to July 2020, nodal involvement, overall stage, type of surgery, time from diagnosis to start of radiotherapy were independently associated with fractionation choice. CONCLUSIONS: There was a striking increase in the use of 26Gy5F dose fractionation regimens for EBC, among women aged ≥50 years, within a month of guidance published at the start of the COVID-19 pandemic in England and Wales
A polymorphic tetranucleotide repeat in the CYP19 gene and male breast cancer
The CYP19 gene codes for the aromatase enzyme that is involved in the synthesis of oestrogens. This case–control study examines the relationship between a tetranucleotide repeat sequence in the CYP19 gene and the development of male breast cancer. No significant differences were found between male breast cancer cases and controls. © 2000 Cancer Research Campaig
Development and characterisation of acquired radioresistant breast cancer cell lines
Table S1. RIN values for all samples used in gene expression analysis. (XLSX 10 kb
Treatment challenges in and outside a specialist network setting: Pancreatic neuroendocrine tumours
Pancreatic Neuroendocrine Neoplasms comprise a group of rare tumours with special biology, an often indolent behaviour and particular diagnostic and therapeutic requirements. The specialized biochemical tests and radiological investigations, the complexity of surgical options and the variety of medical treatments that require individual tailoring, mandate a multidisciplinary approach that can be optimally achieved through an organized network. The present study describes currents concepts in the management of these tumours as well as an insight into the challenges of delivering the pathway in and outside a Network
The High Energy Light Isotope eXperiment program of direct cosmic-ray studies
HELIX is a new NASA-sponsored instrument aimed at measuring the spectra and
composition of light cosmic-ray isotopes from hydrogen to neon nuclei, in
particular the clock isotopes 10Be (radioactive, with 1.4 Myr lifetime) and 9Be
(stable). The latter are unique markers of the production and Galactic
propagation of secondary cosmic-ray nuclei, and are needed to resolve such
important mysteries as the proportion of secondary positrons in the excess of
antimatter observed by the AMS-02 experiment. By using a combination of a 1 T
superconducting magnet spectrometer (with drift-chamber tracker) with a
high-resolution time-of-flight detector system and ring-imaging Cherenkov
detector, mass-resolved isotope measurements of light cosmic-ray nuclei will be
possible up to 3 GeV/n in a first stratospheric balloon flight from Kiruna,
Sweden to northern Canada, anticipated to take place in early summer 2024. An
eventual longer Antarctic balloon flight of HELIX will yield measurements up to
10 GeV/n, sampling production from a larger volume of the Galaxy extending into
the halo. We review the instrument design, testing, status and scientific
prospects.Comment: Presented at the 16th Topical Seminar on Innovative Particle and
Radiation Detectors (IPRD23), Siena, Italy, to appear in JINST Pro
Critical research gaps and translational priorities for the successful prevention and treatment of breast cancer
INTRODUCTION
Breast cancer remains a significant scientific, clinical and societal challenge. This gap analysis has reviewed and critically assessed enduring issues and new challenges emerging from recent research, and proposes strategies for translating solutions into practice.
METHODS
More than 100 internationally recognised specialist breast cancer scientists, clinicians and healthcare professionals collaborated to address nine thematic areas: genetics, epigenetics and epidemiology; molecular pathology and cell biology; hormonal influences and endocrine therapy; imaging, detection and screening; current/novel therapies and biomarkers; drug resistance; metastasis, angiogenesis, circulating tumour cells, cancer 'stem' cells; risk and prevention; living with and managing breast cancer and its treatment. The groups developed summary papers through an iterative process which, following further appraisal from experts and patients, were melded into this summary account.
RESULTS
The 10 major gaps identified were: (1) understanding the functions and contextual interactions of genetic and epigenetic changes in normal breast development and during malignant transformation; (2) how to implement sustainable lifestyle changes (diet, exercise and weight) and chemopreventive strategies; (3) the need for tailored screening approaches including clinically actionable tests; (4) enhancing knowledge of molecular drivers behind breast cancer subtypes, progression and metastasis; (5) understanding the molecular mechanisms of tumour heterogeneity, dormancy, de novo or acquired resistance and how to target key nodes in these dynamic processes; (6) developing validated markers for chemosensitivity and radiosensitivity; (7) understanding the optimal duration, sequencing and rational combinations of treatment for improved personalised therapy; (8) validating multimodality imaging biomarkers for minimally invasive diagnosis and monitoring of responses in primary and metastatic disease; (9) developing interventions and support to improve the survivorship experience; (10) a continuing need for clinical material for translational research derived from normal breast, blood, primary, relapsed, metastatic and drug-resistant cancers with expert bioinformatics support to maximise its utility. The proposed infrastructural enablers include enhanced resources to support clinically relevant in vitro and in vivo tumour models; improved access to appropriate, fully annotated clinical samples; extended biomarker discovery, validation and standardisation; and facilitated cross-discipline working.
CONCLUSIONS
With resources to conduct further high-quality targeted research focusing on the gaps identified, increased knowledge translating into improved clinical care should be achievable within five years
Testicular germ-cell tumours and penile squamous cell carcinoma: Appropriate management makes the difference
Germ-cell tumours (GCT) of the testis and penile squamous cell carcinoma (PeSCC) are a rare and a very rare uro-genital cancers, respectively. Both tumours are well defined entities in terms of management, where specific recommendations - in the form of continuously up-to-dated guide lines-are provided. Impact of these tumour is relevant. Testicular GCT affects young, healthy men at the beginning of their adult life. PeSCC affects older men, but a proportion of these patients are young and the personal consequences of the disease may be devastating. Deviation from recommended management may be a reason of a significant prognostic worsening, as proper treatment favourably impacts on these tumours, dramatically on GCT and significantly on PeSCC. RARECAREnet data may permit to analyse how survivals may vary according to geographical areas, histology and age, leading to assume that non-homogeneous health-care resources may impact the cure and definitive outcomes. In support of this hypothesis, some epidemiologic datasets and clinical findings would indicate that survival may improve when appropriate treatments are delivered, linked to a different accessibility to the best health institutions, as a consequence of geographical, cultural and economic barriers. Finally, strong clues based on epidemiological and clinical data support the hypothesis that treatment delivered at reference centres or under the aegis of a qualified multi-institutional network is associated with a better prognosis of patients with these malignancies. The ERN EURACAN represents the best current European effort to answer this clinical need
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