48 research outputs found

    Small solid renal masses: Characterization by diffusion-weighted MRI at 3 T

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    AIM: To describe the appearance of small solid renal lesions ( 643 cm) on diffusion-weighted magnetic resonance imaging (MRI) and to determine whether ADC measurements may help to differentiate benign from malignant small solid renal masses. METHODS AND MATERIALS: Thirty-five patients with 47 small renal masses (23 malignant, 24 benign) who underwent 3 T MRI of the kidney using diffusion-weighted sequences (b values of 0 and 1000 s/mm(2)) were retrospectively evaluated. Qualitative and quantitative analysis of diffusion-weighted images was performed. RESULTS: Most lesions were hyperintense to kidney on high b-value diffusion-weighted images and hypointense on apparent diffusion coefficient (ADC) map. The mean ADC of the lesions was significantly lower than that of kidney (1.22 \ub1 0.3 versus 1.85 \ub1 0.12 mm(2)/s; p < 0.005). The mean ADC was significantly different between renal cell carcinomas (1.2 \ub1 0.01 mm(2)/s), metastases (1.25 \ub1 0.04 mm(2)/s), angiomyolipoma (1.07 \ub1 0.3 mm(2)/s) and oncocytomas (1.56 \ub1 0.08 mm(2)/s; p < 0.05). The mean ADC of clear cell renal cell carcinomas was significantly different from that of non-clear cell renal cell carcinomas (1.38 \ub1 0.34 versus 0.83 \ub1 0.34 mm(2)/s; p < 0.005). No significant difference was found between mean ADC of fat containing and minimal fat angiomyolipomas (1.06 \ub1 0.48 versus 1.11 \ub1 0.33 mm(2)/s). CONCLUSION: Small solid renal masses are hyperintense on high b value and have different ADC values

    Reachability problems for PAMs

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    Piecewise affine maps (PAMs) are frequently used as a reference model to show the openness of the reachability questions in other systems. The reachability problem for one-dimentional PAM is still open even if we define it with only two intervals. As the main contribution of this paper we introduce new techniques for solving reachability problems based on p-adic norms and weights as well as showing decidability for two classes of maps. Then we show the connections between topological properties for PAM's orbits, reachability problems and representation of numbers in a rational base system. Finally we show a particular instance where the uniform distribution of the original orbit may not remain uniform or even dense after making regular shifts and taking a fractional part in that sequence.Comment: 16 page

    Ideology and moral values in rhetorical framing:How wine was saved from the 19th Century Phylloxera Epidemic

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    Extant organizational research into crises has focused on the efforts of different actors to defend and legitimate their ideologies towards particular actions. Although insightful, such research has offered little knowledge about the moral reasoning underlying such action. In this paper, we explore how moral reasoning from different ideological viewpoints can lead to polarized debates and stalemate within the context of ecological crises. We apply our conceptual framework in an analysis of the 19th century French phylloxera epidemic. Drawing upon this analysis, we argue that, by adapting their moral reasoning, opposing stakeholder groups could maintain their underlying ideology, while at the same time pragmatically changing their actions towards the crisis. We discuss the theoretical implications of our analysis for historical research in organizational studies and research on organizations and the natural environment

    Deep learning-based phenotyping reclassifies combined hepatocellular-cholangiocarcinoma.

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    Primary liver cancer arises either from hepatocytic or biliary lineage cells, giving rise to hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICCA). Combined hepatocellular- cholangiocarcinomas (cHCC-CCA) exhibit equivocal or mixed features of both, causing diagnostic uncertainty and difficulty in determining proper management. Here, we perform a comprehensive deep learning-based phenotyping of multiple cohorts of patients. We show that deep learning can reproduce the diagnosis of HCC vs. CCA with a high performance. We analyze a series of 405 cHCC-CCA patients and demonstrate that the model can reclassify the tumors as HCC or ICCA, and that the predictions are consistent with clinical outcomes, genetic alterations and in situ spatial gene expression profiling. This type of approach could improve treatment decisions and ultimately clinical outcome for patients with rare and biphenotypic cancers such as cHCC-CCA

    Recurrent attacks of acute hepatic porphyria: major role of the chronic inflammatory response in the liver

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    Acute intermittent porphyria (AIP) is an inherited disorder of heme metabolism characterized by life-threatening acute neurovisceral attacks due to the induction of hepatic -aminolevulinic acid synthase 1 (ALAS1) associated with hydroxymethylbilane synthase (HMBS) deficiency. Hemin represses ALAS1 and restores metabolic equilibrium. The main issue in the medical care of AIP patients is the occurrence of debilitating recurrent attacks. Chronically ill patients require repeated hemin infusions and develop secondary hemochromatosis and have a poorer quality of life. To decipher the mechanisms underlying recurrence in AIP patients, we studied the metabolic pathways altered by chronic hemin administration. A follow-up study was conducted between 1974 and 2015 and included 602 French AIP patients, of whom 46 had recurrent AIP. Moreover, we studied the hepatic transcriptome, serum proteome, liver macrophage polarization and oxidative and inflammatory profiles of Hmbs-/- mice chronically treated by hemin and extended the investigations to 5 human explanted livers. The introduction of hemin into the pharmacopeia has coincided with a 4.4-fold increase in the prevalence of chronic patients. We show that repeated hemin infusions trigger a high level heme oxygenase 1 (HO1) response, induce a pro-oxidative iron accumulation and a complex pattern of liver inflammation with macrophage infiltration. Conclusion: chronically heme-treated AIP patients may present with symptoms of an inflammatory disease responsible for an adaptive HO1 induction that could deplete the free heme pool inducing ALAS1. Hemin remains the most effective treatment but should be restricted to patients with severe forms of AIP to prevent chronic damage

    Recurrent attacks of acute hepatic porphyria: major role of the chronic inflammatory response in the liver

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    [Background] Acute intermittent porphyria (AIP) is an inherited disorder of haem metabolism characterized by life‐threatening acute neurovisceral attacks due to the induction of hepatic δ‐aminolevulinic acid synthase 1 (ALAS1) associated with hydroxymethylbilane synthase (HMBS) deficiency. So far, the treatment of choice is hemin which represses ALAS1. The main issue in the medical care of AIP patients is the occurrence of debilitating recurrent attacks. [Objective] The aim of this study was to determine whether chronic hemin administration contributes to the recurrence of acute attacks. [Methods] A follow‐up study was conducted between 1974 and 2015 and included 602 French AIP patients, of whom 46 had recurrent AIP. Moreover, we studied the hepatic transcriptome, serum proteome, liver macrophage polarization and oxidative and inflammatory profiles of Hmbs−/− mice chronically treated by hemin and extended the investigations to five explanted livers from recurrent AIP patients. [Results] The introduction of hemin into the pharmacopeia has coincided with a 4.4‐fold increase in the prevalence of chronic patients. Moreover, we showed that both in animal model and in human liver, frequent hemin infusions generate a chronic inflammatory hepatic disease which induces HO1 remotely to hemin treatment and maintains a high ALAS1 level responsible for recurrence. [Conclusion] Altogether, this study has important impacts on AIP care underlying that hemin needs to be restricted to severe neurovisceral crisis and suggests that alternative treatment targeting the liver such as ALAS1 and HO1 inhibitors, and anti‐inflammatory therapies should be considered in patients with recurrent AIP.LG, JCD, PH, ES and AKA were funded for attending meeting related to ongoing clinical trial by Alnylam Pharmaceuticals.Peer reviewe

    Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques--pulse sequences, analysis algorithms, and applications

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    Cardiovascular magnetic resonance (CMR) tagging has been established as an essential technique for measuring regional myocardial function. It allows quantification of local intramyocardial motion measures, e.g. strain and strain rate. The invention of CMR tagging came in the late eighties, where the technique allowed for the first time for visualizing transmural myocardial movement without having to implant physical markers. This new idea opened the door for a series of developments and improvements that continue up to the present time. Different tagging techniques are currently available that are more extensive, improved, and sophisticated than they were twenty years ago. Each of these techniques has different versions for improved resolution, signal-to-noise ratio (SNR), scan time, anatomical coverage, three-dimensional capability, and image quality. The tagging techniques covered in this article can be broadly divided into two main categories: 1) Basic techniques, which include magnetization saturation, spatial modulation of magnetization (SPAMM), delay alternating with nutations for tailored excitation (DANTE), and complementary SPAMM (CSPAMM); and 2) Advanced techniques, which include harmonic phase (HARP), displacement encoding with stimulated echoes (DENSE), and strain encoding (SENC). Although most of these techniques were developed by separate groups and evolved from different backgrounds, they are in fact closely related to each other, and they can be interpreted from more than one perspective. Some of these techniques even followed parallel paths of developments, as illustrated in the article. As each technique has its own advantages, some efforts have been made to combine different techniques together for improved image quality or composite information acquisition. In this review, different developments in pulse sequences and related image processing techniques are described along with the necessities that led to their invention, which makes this article easy to read and the covered techniques easy to follow. Major studies that applied CMR tagging for studying myocardial mechanics are also summarized. Finally, the current article includes a plethora of ideas and techniques with over 300 references that motivate the reader to think about the future of CMR tagging
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