1,147 research outputs found

    Primary aldosteronism: The role of plasma free metanephrines as a lateralization marker in adrenal vein sampling and its concordance with CT-scan

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    Background: Primary aldosteronism (PA) is a common cause of secondary hypertension found in 5 to 10% of the hypertensive patients. The diagnostic of PA is important because it is associated with adverse cardiovascular outcomes and may be cured with surgery. The principal forms of PA are the adrenal adenoma (unilateral) and the hyperplasia of adrenal glands (bilateral). Adrenal vein sampling (AVS) is considered the gold standard to distinguish the unilateral from the bilateral form of PA. Compared to computed tomography scanners (CT-scan), AVS is often discordant. This discordance could be secondary to a lack of sensitivity of cortisol, the marker used to assess lateralization. Free metanephrines (fMN), which are continuously released by the adrenal gland could be a potential alternative. We hypothesized that the discordance with CT-scans would be lower when fMN were used as marker of lateralization. Objective: To compare the concordance of adrenal angio-CT with AVS using cortisol (control marker) and free metanephrine (new marker) as AVS lateralization markers. Methods: This study was prospective and monocentric. Patients with PA who had both a CT-scan and a bilaterally selective AVS and were included in the analysis. A Fisher exact test was used to compare the two methods (AVS and CT-san) with each marker. A Cohen’s kappa coefficient was then used to compare the level of agreement. Results: A total of 101 participants (42 women/49 men) were included in the Study. Using a cut-off level of 3 for lateralization, the levels of agreement of CT-scan with AVS using fMN was 0.3010.072 compared to 0.2720.070 with AVS using cortisol. Using a cut-off level of 5 for lateralization, the levels of agreement of CT-scan with AVS using fMN was 0.2470.066 compared to 0.1950.064 with AVS using cortisol. The best agreement between AVS using PCC and PFMC is when the less stringent lateralization index is used (3 vs 5). Conclusion: The use of plasma free metanephrine concentration as a maker for lateralization only marginally improved the concordance of AVS compard to CT-scan. It confirms that the decision to surgically or pharmacologically treat patient with hypertension should no rely solely on imagery. More studies are needed to determine the utility of fMN in the interpretation of AVS lateralization

    Computed tomography angiography for the diagnosis of coronary artery disease among patients undergoing transcatheter aortic valve implantation

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    Background Coronary artery disease (CAD) is frequently seen in patients suffering from severe aortic valve stenosis (AS), as both pathologies share the same pathophysiology. In a transcatheter aortic valve implantation (TAVI) work-up, patients beneficiate from both computed tomography angiography (CTA) and invasive coronary angiography (ICA). Some studies evaluated the performance of CTA to diagnose CAD among patients undergoing TAVI and showed interesting results1-4. Nevertheless, data remain scarce and this diagnostic method is not validated in this population. In this context, we thought to evaluate the diagnostic performance of CTA to diagnose CAD among patients selected for TAVI. Methods A total of 199 patients that had a TAVI in the Lausanne University Hospital between the 1st of June 2013 and the 31st of December 2017 were retrospectively included. Exclusion criteria were coronary artery bypass graft (CABG) prior to CTA and unavailable CTA images. Finally, 127 patients were included. Two independent radiologists – blinded for ICA report – were asked to read the CTA of these patients and to indicate the presence of ≥50% and ≥70% stenosis in the 4 main coronary vessels. Their evaluation was then compared with ICA reports and analyses were performed at vessel and patient levels. Results A total of 342 vessels were analyzable. Based on ICA, significant CAD (at least 1 ≥50% stenosis) was present in 49 (38.6%) patients. Severe CAD (≥70% stenosis) was found in 29 (22.8%) patients. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CTA to diagnose significant CAD were 81.1%, 87.9%, 44.8%, 97.5% and 87.1% at vessel level using the cut-off of 50% and 42.8%, 97.8%, 56.3%, 96.3% and 94.4% for severe CAD, using the cut-off of 70%. At patient level, sensitivity, specificity, positive and negative predictive values were respectively 84.6%, 64.6%, 56.4% and 88.6% for significant CAD. Conclusion Pre-TAVI CTA shows good performance to rule out significant and severe CAD and could be used as a gatekeeper for ICA. Positive findings on CTA should be confirmed with ICA given the low positive predictive value

    Developmental Bayesian Optimization of Black-Box with Visual Similarity-Based Transfer Learning

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    We present a developmental framework based on a long-term memory and reasoning mechanisms (Vision Similarity and Bayesian Optimisation). This architecture allows a robot to optimize autonomously hyper-parameters that need to be tuned from any action and/or vision module, treated as a black-box. The learning can take advantage of past experiences (stored in the episodic and procedural memories) in order to warm-start the exploration using a set of hyper-parameters previously optimized from objects similar to the new unknown one (stored in a semantic memory). As example, the system has been used to optimized 9 continuous hyper-parameters of a professional software (Kamido) both in simulation and with a real robot (industrial robotic arm Fanuc) with a total of 13 different objects. The robot is able to find a good object-specific optimization in 68 (simulation) or 40 (real) trials. In simulation, we demonstrate the benefit of the transfer learning based on visual similarity, as opposed to an amnesic learning (i.e. learning from scratch all the time). Moreover, with the real robot, we show that the method consistently outperforms the manual optimization from an expert with less than 2 hours of training time to achieve more than 88% of success

    Treatment of Rat Liver Microsomes with Phospholipase C: Effect on Phospholipids and on Cytochromes P450 and b5

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    Treatment of rat liver microsomes with phospholipase C (CL weLchii) revealed the following: 1. The polar headgroups of 70°/o of the phospholipids can be removed by treatment of microsomes with phospholipase C. When phospholipids that have been extracted from microsomes are treated with phospholipase C, 900/o can be hydrolyzed, suggesting that certain phospholipids are protected from the enzyme in situ. 2. Neither the native conformations of cytochromes P450 and b5 nor their binding to the microsomal membrane are directly affected by phospholipase C treatment. 3. The diglycerides resulting from the action of phospholipase C can be hydrolyzed by an enzyme in the microsomal membrane to yield free fatty acids which partially denature cytochrome P450. 4. The pattern of this partial denaturation is a further indication of the existence of a number of cytochrome P450 species in the microsomal membrane

    Energy levels in resting and mitogen-stimulated human lymphocytes during treatment with FK506 or cyclosporin A in vitro

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    AbstractBy employing microcalorimetry to assess overall metabolic activity in combination with other assays for specific metabolic events, we have investigated the influence of cyclosporin A and FK506 on the metabolic status of resting and mitogen-stimulated human peripheral lymphocytes. Both cyclosporin A and FK506 significantly reduced heat output from resting lymphocytes. This reduction could not be correlated with effects on DNA synthesis, lactate production, ATP levels or mitochondrial uptake of Rhodamine 123. These two drugs also potently reduced the increase in heat output seen during mitogen stimulation of lymphocytes. Both cyclosporin A and FK506 also prevented the increase in DNA synthesis, lactate production and ATP levels seen in response to mitogen stimulation. The increase in mitochondrial uptake of Rhodamine 123 during blastoid transformation was significantly reduced only by cyclosporin A. We ascribe the major part of the effects of these compounds to inhibition of the glycolytic pathway in both resting and mitogen-stimulated lymphocytes. These results indicate that the immunosuppressants cyclosporin A and FK506 exert other effects on lymphocytes than their well-established inhibitory action on calcineurin.© 1997 Elsevier Science B.V. All rights reserved

    Thyroid Control over Biomembranes

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65831/1/j.1432-1033.1980.tb04795.x.pd
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