266 research outputs found

    How Do Payers Respond to Regulatory Actions? The Case of Bevacizumab

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    In February 2008, the US Food and Drug Administration (FDA) granted accelerated approval for bevacizumab for metastatic breast cancer. After public hearings in July 2010, and June 2011, the FDA revoked this approved indication in November 2011, on the basis of additional evidence regarding its risk/benefit profile. The Centers for Medicare and Medicaid Services, local Medicare contractors, and commercial payers varied in their stated intentions to cover bevacizumab after FDA's regulatory actions. We examined payer-specific trends in bevacizumab use after the FDA's regulatory actions

    Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

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    After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40–60 s and separated by quiescent episodes lasting 40–200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle

    Design development post contract signing in New Zealand:Client's or contractor's cost?

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    By offering fixed-price contracts for designs supplied by clients, contractors legally warrant that they can build what has been designed and do so within their fixed price. Yet detailed drawings are often issued during construction in response to contractors' requests for information on the basis that they cannot otherwise build what has been designed. Claim-entitlement decisions are often made by construction professionals (architects, engineers and quantity surveyors) without legal training in contractual interpretation, potentially varying who pays for design development after contract signing, contractors or clients. Prior studies have addressed buildability obligations relating to ground conditions and foundations. This study applies key principles of contract law to consider who should pay for instructed drawing details post contract signing under the New Zealand standard NZS 3910:2013, 'Conditions of contract for building and civil engineering construction', in terms of (a) when a variation claim may be accepted; (b) the effect of contractor involvement on design development; and (c) the effect if claimed from a building subcontractor to a consultant manager (no head contractor). A claim-entitlement flow chart and a table comparing the head contractor's and consultant construction manager's obligations provide practical guides for contract administrators. Identifying terms prone to interpretation informs contract drafters towards reducing ambiguity for contract users and therefore the potential for dispute

    An empirical approach to the nucleation of sulfuric acid droplets in the atmosphere

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    We use quantum mechanical evaluations of the Gibbs free energy of the hydrates of sulfuric acid, H2SO4. nH2O and (H2SO4)2 . nH2O to evaluate an empirical surface tension for sulfuric acid-water clusters containing few molecules. We use this surface tension to evaluate nucleation rates using classical heteromolecular theory. At low temperatures (T 213 K) the nucleation rates obtained with the empirical surface tensions are signifi cantly greater than those using bulk values of the surface tension. At higher temperatures the difference disappears

    A phase III clinical trial of exercise modalities on treatment side-effects in men receiving therapy for prostate cancer

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    Background: Androgen deprivation therapy (ADT) is accompanied by a number of adverse side effects including reduced bone mass and increased risk for fracture, reduced lean mass and muscle strength, mood disturbance and increased fat mass compromising physical functioning, independence, and quality of life. The purpose of this investigation is to examine the effects of long term exercise on reversing musculoskeletal-related side effects, and cardiovascular and diabetes risk factors in men receiving androgen deprivation for their prostate cancer. Specifically, we aim to investigate the effects of a 12-month exercise program designed to load the musculoskeletal system and reduce cardiovascular and diabetes disease progression on the following primary endpoints: 1) bone mineral density; 2) cardiorespiratory function and maximal oxygen capacity; 3) body composition (lean mass and fat mass); 4) blood pressure and cardiovascular function; 5) lipids and glycemic control; and 6) quality of life and psychological distress

    Border effects among Catalan dialects

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    In this study, we investigate which factors influence the linguistic distance of Catalan dialectal pronunciations from standard Catalan. We use pronunciations from three regions where the northwestern variety of the Catalan language is spoken (Catalonia, Aragon and Andorra). In contrast to Aragon, Catalan has an official status in both Catalonia and Andorra, which likely influences standardization. Because we are interested in the potentially large range of differences that standardization might promote, we examine 357 words in Catalan varieties and in particular their pronunciation distances with respect to the standard. In order to be sensitive to differences among the words, we fitted a generalized additive mixed-effects regression model to this data. This allows us to examine simultaneously the general (i.e. aggregate) patterns in pronunciation distance and to detect those words that diverge substantially from the general pattern. The results revealed higher pronunciation distances from standard Catalan in Aragon than in the other regions. Furthermore, speakers in Catalonia and Andorra, but not in Aragon, showed a clear standardization pattern, with younger speakers having dialectal pronunciations closer to the standard than older speakers. This clearly indicates the presence of a border effect within a single country with respect to word pronunciation distances. Since a great deal of scholarship focuses on single segment changes, we compare our analysis to the analysis of three segment changes that have been discussed in the literature on Catalan. This comparison revealed that the pattern observed at the word pronunciation level was supported by two of the three cases examined. As not all individual cases conform to the general pattern,

    Reduced synthesis of the Ybt siderophore or production of aberrant Ybt-like molecules activates transcription of yersiniabactin genes in Yersinia pestis

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    Synthesis of the siderophore yersiniabactin (Ybt) proceeds by a mixed nonribosomal peptide synthetase/polyketide synthase mechanism. Transcription of ybt genes encoding biosynthetic and transport functions is repressed under excess iron conditions by Fur, but is also activated by Ybt via the transcriptional regulator YbtA. While mutations in most biosynthetic genes and ybtA negate transcription activation from the regulated promoters, three biosynthetic mutations do not reduce this transcriptional activation. Here we show that two of these mutants, one lacking the putative type II thioesterase (TE) YbtT and the other with a mutation in the TE domain of HMWP1, produce reduced levels of authentic Ybt that are capable of signalling activity. Alanine substitutions in two residues of YbtT that are essential for catalytic activity in other type II TEs reduced the ability of Yersinia pestis to grow under iron-chelated conditions. The third mutant, which lacks the salicylate synthase YbtS, did not make authentic Ybt but did produce a signalling molecule. Finally, a Δpgm strain of Y. pestis, which lacks essential Ybt biosynthetic genes, also produced a signalling molecule that can activate transcription of ybt genes. The non-Ybt signal molecules from these two mutants are likely separate compounds. While these compounds are not biologically relevant to normal Ybt regulation, a comparison of the structures of Ybt and other signalling molecules will help in determining the chemical structures recognized as a Ybt signal

    Acquired pure red cell aplasia: updated review of treatment

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    Pure red cell aplasia (PRCA) is a syndrome characterized by a severe normocytic anaemia, reticulocytopenia, and absence of erythroblasts from an otherwise normal bone marrow. Primary PRCA, or secondary PRCA which has not responded to treatment of the underlying disease, is treated as an immunologically-mediated disease. Although vigorous immunosuppressive treatments induce and maintain remissions in a majority of patients, they carry an increased risk of serious complications. Corticosteroids were used in the treatment of PRCA and this has been considered the treatment of first choice although relapse is not uncommon. Cyclosporine A (CsA) has become established as one of the leading drugs for treatment of PRCA. However, common concerns have been the number of patients treated with CsA who achieve sustained remissions and the number that relapse. This article reviews the current status of CsA therapy and compares it to other treatments for diverse PRCAs

    Crop modelling: towards locally relevant and climate-informed adaptation

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    A gap between the potential and practical realisation of adaptation exists: adaptation strategies need to be both climate-informed and locally relevant to be viable. Place-based approaches study local and contemporary dynamics of the agricultural system, whereas climate impact modelling simulates climate-crop interactions across temporal and spatial scales. Crop-climate modelling and place-based research on adaptation were strategically reviewed and analysed to identify areas of commonality, differences, and potential learning opportunities to enhance the relevance of both disciplines through interdisciplinary approaches. Crop-modelling studies have projected a 7–15% mean yield change with adaptation compared to a non-adaptation baseline (Nature Climate Change 4:1–5, 2014). Of the 17 types of adaptation strategy identified in this study as place-based adaptations occurring within Central America, only five were represented in crop-climate modelling literature, and these were as follows: fertiliser, irrigation, change in planting date, change in cultivar and area cultivated. The breath and agency of real-life adaptation compared to its representation in modelling studies is a source of error in climate impact simulations. Conversely, adaptation research that omits assessment of future climate variability and impact does not enable to provide sustainable adaptation strategies to local communities so risk maladaptation. Integrated and participatory methods can identify and reduce these sources of uncertainty, for example, stakeholder’s engagement can identify locally relevant adaptation pathways. We propose a research agenda that uses methodological approaches from both the modelling and place-based approaches to work towards climate-informed locally relevant adaptation

    Large-scale gene-centric analysis identifies novel variants for coronary artery disease

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    Coronary artery disease (CAD) has a significant genetic contribution that is incompletely characterized. To complement genome-wide association (GWA) studies, we conducted a large and systematic candidate gene study of CAD susceptibility, including analysis of many uncommon and functional variants. We examined 49,094 genetic variants in ~2,100 genes of cardiovascular relevance, using a customised gene array in 15,596 CAD cases and 34,992 controls (11,202 cases and 30,733 controls of European descent; 4,394 cases and 4,259 controls of South Asian origin). We attempted to replicate putative novel associations in an additional 17,121 CAD cases and 40,473 controls. Potential mechanisms through which the novel variants could affect CAD risk were explored through association tests with vascular risk factors and gene expression. We confirmed associations of several previously known CAD susceptibility loci (eg, 9p21.3:p&lt;10-33; LPA:p&lt;10-19; 1p13.3:p&lt;10-17) as well as three recently discovered loci (COL4A1/COL4A2, ZC3HC1, CYP17A1:p&lt;5×10-7). However, we found essentially null results for most previously suggested CAD candidate genes. In our replication study of 24 promising common variants, we identified novel associations of variants in or near LIPA, IL5, TRIB1, and ABCG5/ABCG8, with per-allele odds ratios for CAD risk with each of the novel variants ranging from 1.06-1.09. Associations with variants at LIPA, TRIB1, and ABCG5/ABCG8 were supported by gene expression data or effects on lipid levels. Apart from the previously reported variants in LPA, none of the other ~4,500 low frequency and functional variants showed a strong effect. Associations in South Asians did not differ appreciably from those in Europeans, except for 9p21.3 (per-allele odds ratio: 1.14 versus 1.27 respectively; P for heterogeneity = 0.003). This large-scale gene-centric analysis has identified several novel genes for CAD that relate to diverse biochemical and cellular functions and clarified the literature with regard to many previously suggested genes.</p
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