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Insights for Antihypertensive pharmacotherapy from the “Calcium Paradox” due to Ca2+/camp Interaction

Published on: 27th March, 2017

OCLC Number/Unique Identifier: 7317653234

Several experimental studies performed since 1975, using smooth muscles richly innervated by sympathetic nerves to exclude the autonomic influence of adjusting reflex (rodent vas deferens), showed that L-type voltage-activated Ca2++ channels (VACC) blockers completely inhibited neurogenic contractions induced by electrical field stimulation (EFS) in high concentrations (>10-6 M), but paradoxically increased these EFS-contractions in low concentrations (<10-6 M), suggesting that other mechanisms than only autonomic adjusting reflex are involved in these paradoxical effects. In 2013, we showed that these paradoxical effects of L-type VACC blockers, named by us “calcium paradox” phenomenon, were potentiated by drugs which increase cytosolic cAMP concentration ([cAMP] c-enhancers), such as rolipram, IBMX and forskolin, indicating that this sympathetic hyperactivity drug-induced is due to interaction of the Ca2+/cAMP intracellular signaling pathways (Ca2+/cAMP interaction). Then, the pharmacological manipulation of this interaction produced by combination of the L-type VACC blockers used in the antihypertensive therapy, and [cAMP] c-enhancers used in the antidepressive therapy, could represent a potential cardiovascular risk for hypertensive patients due to sympathetic hyperactivity. Then, we discussed the role of Ca2+/cAMP interaction for antihypertensive pharmacotherapy.
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Reliability and Diagnostic Performance of Transient Hepatic Elastography in Chronic Hepatitis C during the Training Phase

Published on: 2nd August, 2024

Chronic infection with the hepatitis C virus (HCV) is estimated to affect 58 million people worldwide and around 700,000 individuals in Brazil. Various non-invasive markers of hepatic fibrosis have been proposed, such as transient hepatic elastography (THE) using FibroScan®. However, the reliability of the performance, by operators in the training phase is undetermined, which hinders its applicability in clinical practice. Objectives: The present study aimed to evaluate the impact of training an inexperienced operator to perform the examinations using FibroScan® in patients with chronic hepatitis C. Specifically, the frequency of unreliable results throughout the training was assessed. Methods: This is a cross-sectional study with retrospective data collection including compensated chronic hepatitis C patients who underwent the examinations using FibroScan® between March 2014 and December 2016, performed by two researchers. Included patients were divided into two groups based on the operator's experience in the examination: the Experienced Examiner (EE) group and the Examiner in Training (ET) group, with the latter divided into two phases: phase 1, consisting of the first 100 examinations, and phase 2, comprising subsequent examinations. For the reliability analysis, parameters such as success rate (SR), interquartile range (IQR) to median (Md) ratio (IQR/Md), and reliability criteria of Castéra, et al. and Boursier, et al. were used. Results: Between March 2014 and December 2016, 771 adult HCV-infected individuals were evaluated and divided into EE group (n = 161), ET phase 1 (n = 100), and ET phase 2 (n = 158), showing similar demographic, clinical, and laboratory characteristics. SR and IQR/Md ratios were similar among EE, ET phase 1, and ET phase 2 groups. The proportion of reliable results was comparable in all three groups, using Castéra, et al. reliability criteria (92.5%, 92.0%, and 97.5%, respectively) and Boursier, et al. criteria (96.9%, 95.0%, and 98.1%, respectively). Conclusion: A short training period (up to 100 examinations) seems to be sufficient for them to have good clinical applicability in the hands of an operator with initial experience in the method
Cite this ArticleCrossMarkPublonsHarvard Library HOLLISGrowKudosResearchGateBase SearchOAI PMHAcademic MicrosoftScilitSemantic ScholarUniversite de ParisUW LibrariesSJSU King LibrarySJSU King LibraryNUS LibraryMcGillDET KGL BIBLiOTEKJCU DiscoveryUniversidad De LimaWorldCatVU on WorldCat
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