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Search Results: 1 - 10 of 220431 matches for " Gillian C Barnett "
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Genetics and genomics of radiotherapy toxicity: towards prediction
Catharine M West, Gillian C Barnett
Genome Medicine , 2011, DOI: 10.1186/gm268
Abstract: Since the discovery of radiation at the end of the 19th century, radiotherapy has become one of the most important modalities for treating cancer. The schedules (total radiation dose, dose per fraction, number of fractions, overall treatment time and volume irradiated) have been developed to maximize tumor kill and minimize normal tissue damage. The radiation dose prescribed depends on the cancer type and surrounding normal tissue tolerance. Doses are generally given so that <5% of patients suffer serious toxicity up to 5 years following radiotherapy [1,2]. Serious side effects such as bowel obstruction and incontinence can occur months to years after treatment, be extremely debilitating and impact negatively on the quality-of-life of cancer survivors.Given the millions of cancer survivors worldwide, estimated at 2 million in the UK and 12 million in the USA, there is a need to increase our understanding of the molecular pathogenesis of radiotherapy toxicity, find ways of predicting those patients likely to suffer with long-term side effects, and develop new approaches for their amelioration. As there is a direct relationship between radiation dose and tumor control, the development of side effects in a minority limits the dose that can be safely prescribed to the majority of patients. Development of a test to predict those likely to suffer side effects should enable individualized radiation dose prescription to increase cancer cure while reducing the number of survivors suffering with the consequences of treatment.In this review, we outline the current radiotherapy approaches and understanding of how this treatment works. Then we discuss toxicity and the importance of genetics. We then focus on recent developments in identifying the genetic variants underlying radiosensitivity and the results from the first genome-wide association studies (GWASs), which suggested that a polymorphism in the follicle-stimulating hormone receptor (FSHR) gene might be associated with e
Post-Operative Radiotherapy for Soft Tissue Sarcoma of the Anterior Compartment of the Thigh: Should the Sartorius Muscle be Included?
Gillian C. Barnett,Andrew C. F. Hoole,Nicola Twyman,Sarah J. Jefferies,Neil G. Burnet
Sarcoma , 2005, DOI: 10.1080/13577140400025961
Abstract: Purpose: The clinical target volume (CTV) of post-operative radiotherapy for soft tissue sarcoma of the limbs conventionally includes the whole of the transverse cross-section of the affected anatomical compartment. In the anterior thigh sartorius appears to lie within its own fascial compartment and can be safely excluded. We investigated the potential impact of omitting sartorius from the anterior muscle compartment on patients with soft tissue sarcoma of the thigh.
Land of a Couple of Dances: Global and Local Influences on Freestyle Play in Dance Dance Revolution
Fibreculture Journal , 2006,
Abstract: This paper traces successful and unsuccessful attempts to shape the meanings of the video game Dance Dance Revolution, specifically with reference to what "dancing" means in this context, as the game moves between various interested parties - game developers, players, Internet forum participants, and other media producers. Drawing on Actor-Network Theory and the network analyses of Manuel Castells, the paper reconstructs the forces shaping players' stylistic decisions through an analysis of dance game machines and software, and of a single forum thread on DDRFreak.com, a major website in the dance game community. The paper asks who decides how DDR players dance and at what times? Are the decisions about play made in the development meeting, the arcade, competitions, online or around the home console? Globally, how do some regions or groups emerge as experts or leaders in play style? Analysis indicates that within the United States, Californian players from major cities dominate discussion, supported by the global flows of people, resources, and capital through the state. The dominant players support their stated norms for play through recourse to mainstream conceptions of masculinity, rap music and associated styles of dance.
Within-stem denstiy variations of two lesser-utilized timbers and their related primary species
C Antwi-Boasiako, JR Barnett
Journal of Science and Technology (Ghana) , 2009,
Abstract: Wood density often influences its quality, marketability and end-use. This paper provides information, for the first time, on the density variation within the stems of two members each of the Rubiaceae and the Tiliaceae from Ghana. From each family, the density at each stem position of a traditional species is compared with that of a related Lesser-Utilized Species (LUS). Density is determined using conditioned weight of each block at 20oC and 65%rh and its volume measured using a digital micrometer. Densities ranging from 720-820kg/m3 for Corynanthe pachyceras Welw., and 660 -720kg/m3 for Nauclea diderrichii (de Wild.) Merr. (members of the Rubiaceae) were measured. Densities for the two members of the Tiliaceae are lower and range from 295-400kg/m3 for Glyphaea brevis (Sprengel) Monachino and 640-700kg/m3 for Nesogordonia papaverifera (A. Chev.) R. Capuron. Analysis of variance (ANOVA) is employed to examine differences in densities from different radial and axial stem positions as well as growth sites for the two (2) LUS. Results have shown that variations in density within the stems exist with density increasing generally from the outer sapwood to the inner heartwood. However, the trend is sometimes not clear for members of the Tiliaceae (G. brevis and N. papaverifera). It also varies along the stems of the four timbers often decreasing with height from the base to the crown. However, few irregularities also occur along the stems of the LUS. Moreover, this study has shown that growth site influences the within-stem densities of the LUS.
A Graph Theoretic Interpretation of Neural Complexity
L. Barnett,C. L. Buckley,S. Bullock
Quantitative Biology , 2010,
Abstract: One of the central challenges facing modern neuroscience is to explain the ability of the nervous system to coherently integrate information across distinct functional modules in the absence of a central executive. To this end Tononi et al. [Proc. Nat. Acad. Sci. USA 91, 5033 (1994)] proposed a measure of neural complexity that purports to capture this property based on mutual information between complementary subsets of a system. Neural complexity, so defined, is one of a family of information theoretic metrics developed to measure the balance between the segregation and integration of a system's dynamics. One key question arising for such measures involves understanding how they are influenced by network topology. Sporns et al. [Cereb. Cortex 10, 127 (2000)] employed numerical models in order to determine the dependence of neural complexity on the topological features of a network. However, a complete picture has yet to be established. While De Lucia et al. [Phys. Rev. E 71, 016114 (2005)] made the first attempts at an analytical account of this relationship, their work utilized a formulation of neural complexity that, we argue, did not reflect the intuitions of the original work. In this paper we start by describing weighted connection matrices formed by applying a random continuous weight distribution to binary adjacency matrices. This allows us to derive an approximation for neural complexity in terms of the moments of the weight distribution and elementary graph motifs. In particular we explicitly establish a dependency of neural complexity on cyclic graph motifs.
Evaluation of the Cytotoxic and Genotoxic Potential of Khat (Catha edulis Forsk) Extracts on Human T Lymphoblastoid Cell Line
S.S. Barkwan,C.R. Barnett,Y.A. Barnett,P.T. Tomkins
Journal of Medical Sciences , 2004,
Abstract: This paper reports on an investigation of the cytotoxic and genotoxic potential of khat extract using a human T lymphoblastoid cell line (CEM). Exponentially growing CEM cells were cultured for 12 h in the presence of khat extract (0-2000 μg ml-1). Statistically significant, dose-dependent increases in; CEM cell death at dose (> 400 μg ml-1), in DNA damage at dose (>200 μg ml-1) and in micronuclei frequency, at dose (>200 μg ml-1) were observed. The genetic damage effects of khat extract on human cell line observed in this study could serve as a major contribution towards the understanding and creating of awareness of an increased risk of cancer amongst long-term khat consumers.
Insect Detection of Small Targets Moving in Visual Clutter
Karin Nordstr?m,Paul D. Barnett,David C. O'Carroll
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0040054
Abstract: Detection of targets that move within visual clutter is a common task for animals searching for prey or conspecifics, a task made even more difficult when a moving pursuer needs to analyze targets against the motion of background texture (clutter). Despite the limited optical acuity of the compound eye of insects, this challenging task seems to have been solved by their tiny visual system. Here we describe neurons found in the male hoverfly,Eristalis tenax, that respond selectively to small moving targets. Although many of these target neurons are inhibited by the motion of a background pattern, others respond to target motion within the receptive field under a surprisingly large range of background motion stimuli. Some neurons respond whether or not there is a speed differential between target and background. Analysis of responses to very small targets (smaller than the size of the visual field of single photoreceptors) or those targets with reduced contrast shows that these neurons have extraordinarily high contrast sensitivity. Our data suggest that rejection of background motion may result from extreme selectivity for small targets contrasting against local patches of the background, combined with this high sensitivity, such that background patterns rarely contain features that satisfactorily drive the neuron.
Statistical issues in randomized trials of cancer screening
Stuart G Baker, Barnett S Kramer, Philip C Prorok
BMC Medical Research Methodology , 2002, DOI: 10.1186/1471-2288-2-11
Abstract: Our emphasis is on simple approaches.We make the following recommendations:(1) Use death from cancer as the primary endpoint, but review death records carefully and report all causes of death(2) Use a simple "causal" estimate to adjust for nonattendance and contamination occurring immediately after randomization(3) Use a simple adaptive estimate to adjust for dilution in follow-up after the last screenThe proposed guidelines combine recent methodological work on screening endpoints and noncompliance/contamination with a new adaptive method to adjust for dilution in a study where follow-up continues after the last screen. These guidelines ensure good practice in the design and analysis of randomized trials of cancer screening.The evaluation of randomized trials of cancer screening involves special statistical considerations. Although some of these considerations have been previously discussed [1,2], our emphasis is on recent and new methodologies that are easy to implement. Throughout the article, when we refer to cancer we mean the target cancer of the screening test.To better appreciate some of the issues, we review common biases associated with a na?ve analysis of cancer screening data. These biases arise when comparing survival after cancer detection between screen-detected and clinically detected cancer cases. To better explain these biases we introduce a novel analogy.Detection of an asymptomatic cancer by screening starts the clock at a younger age so the survival time from screen detection is longer than the survival time from clinical detection, even if screening does not change the age of death. As an analogy, imagine waiting at a bus stop C for a bus traveling north to destination D. Suppose you walk south and board the same bus at stop B prior to its arrival at C. Although the bus ride from B to D is longer than from C to D (by the lead time from B to C), the arrival time at D is unchanged. You have simply spent more of your life on the bus. The travel ti
Subcellular localization of Mayven following expression of wild type and mutant EGFP tagged cDNAs
Paul Montague, Peter GE Kennedy, Susan C Barnett
BMC Neuroscience , 2010, DOI: 10.1186/1471-2202-11-63
Abstract: The subcellular location of Mayven in OEC transfectants showed a characteristic distribution with intense foci of staining towards the process tips corresponding to regions of accumulated Mayven overlapping in part with lammelipodial actin and was absent from the filipodia and the outer membrane. This signature pattern was also observed in Schwann cells, Oli-Neu cells, astrocytes and the neuroblastoma cell line B104 transfectants and resembled the exogenous and endogenous Mayven distribution in oligodendrocytes. This contrasted with the localization pattern in non-neural cells. There was a re-localization of Mayven in OEC transfectants following drug treatment to challenge the integrity of the actin cytoskeleton while breakdown of the microtubular component had no discernible impact on the accumulation of Mayven in the process tips. Deletion of the first three amino acids of the SH3 motif of the putative Fyn Kinase binding domain at the amino terminus significantly compromised this signature pattern as did the removal of the last Kelch repeat unit of six unit Kelch domain comprising the carboxyl terminus. In addition, there was a reduction in process length in mutant transfectants. Co-expression studies with a haemagglutinin (HA) tagged wild type Mayven cDNA and EGFP tagged mutant cDNAs suggested a homomeric interaction mediated by the BTB/POZ domain.Exogenous Mayven is transported to the lamellipodia in neural transfectants associating with the actin cytoskeletal network. In addition to the importance of the internal BTB/POZ domain, this subcellular distribution pattern is dependent on the presence of an intact amino and carboxyl terminus.Actin polymerization driven membrane protrusion, initially results in the formation of fine filipodia projections comprising parallel actin bundles. The filipodia widen to form lamellipodia by creating a branched mesh network of orthogonal actin. Consequent recruitment of microtubules provides mechanical stability to the extending
General practice training and virtual communities of practice - a review of the literature
Barnett Stephen,Jones Sandra C,Bennett Sue,Iverson Don
BMC Family Practice , 2012, DOI: 10.1186/1471-2296-13-87
Abstract: Background Good General Practice is essential for an effective health system. Good General Practice training is essential to sustain the workforce, however training for General Practice can be hampered by a number of pressures, including professional, structural and social isolation. General Practice trainees may be under more pressure than fully registered General Practitioners, and yet isolation can lead doctors to reduce hours and move away from rural practice. Virtual communities of practice (VCoPs) in business have been shown to be effective in improving knowledge sharing, thus reducing professional and structural isolation. This literature review will critically examine the current evidence relevant to virtual communities of practice in General Practice training, identify evidence-based principles that might guide their construction and suggest further avenues for research. Methods Major online databases Scopus, Psychlit and Pubmed were searched for the terms “Community of Practice” (CoP) AND (Online OR Virtual OR Electronic) AND (health OR healthcare OR medicine OR “Allied Health”). Only peer-reviewed journal articles in English were selected. A total of 76 articles were identified, with 23 meeting the inclusion criteria. There were no studies on CoP or VCoP in General Practice training. The review was structured using a framework of six themes for establishing communities of practice, derived from a key study from the business literature. This framework has been used to analyse the literature to determine whether similar themes are present in the health literature and to identify evidence in support of virtual communities of practice for General Practice training. Results The framework developed by Probst is mirrored in the health literature, albeit with some variations. In particular the roles of facilitator or moderator and leader whilst overlapping, are different. VCoPs are usually collaborations between stakeholders rather than single company VCoPs. Specific goals are important, but in specialised health fields sometimes less important than in business. Boundary spanning can involve the interactions of different professional groups, as well as using external experts seen in business VCoPs. There was less use of measurement in health VCoPs. Environments must be supportive as well as risk free. Additional findings were that ease of use of technology is paramount and it is desirable for VCoPs to blend online and face-to-face involvement. Conclusions The business themes of leadership, sponsorship, objectives and goals, boundary spanning
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