Elisa Cairrao

Bio: Elisa Cairrao is an academic researcher from University of Beira Interior. The author has contributed to research in topics: Medicine & Voltage-dependent calcium channel. The author has an hindex of 16, co-authored 47 publications receiving 965 citations. Previous affiliations of Elisa Cairrao include University of Aveiro.

Cyclic nucleotide-dependent relaxation pathways in vascular smooth muscle

Abstract: Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (vasoconstriction) and release of force (vasodilation). The initiation of force is associated with increases in intracellular calcium concentrations, activation of myosin light-chain kinase, increases in the phosphorylation of the regulatory myosin light chains, and actin-myosin crossbridge cycling. There are, however, several signaling pathways modulating Ca2+ mobilization and Ca2+ sensitivity of the contractile machinery that secondarily regulate the contractile response of vascular smooth muscle to receptor agonists. Among these regulatory mechanisms involved in the physiological regulation of vascular tone are the cyclic nucleotides (cAMP and cGMP), which are considered the main messengers that mediate vasodilation under physiological conditions. At least four distinct mechanisms are currently thought to be involved in the vasodilator effect of cyclic nucleotides and their dependent protein kinases: (1) the decrease in cytosolic calcium concentration ([Ca2+]c), (2) the hyperpolarization of the smooth muscle cell membrane potential, (3) the reduction in the sensitivity of the contractile machinery by decreasing the [Ca2+]c sensitivity of myosin light-chain phosphorylation, and (4) the reduction in the sensitivity of the contractile machinery by uncoupling contraction from myosin light-chain phosphorylation. This review focuses on each of these mechanisms involved in cyclic nucleotide-dependent relaxation of vascular smooth muscle under physiological conditions.

Potassium channels are involved in testosterone-induced vasorelaxation of human umbilical artery

Abstract: Recent studies have shown that testosterone induces relaxation of different arteries, although the mechanism of this action is still under debate. We investigated the involvement of potassium channels in this mechanism. Using standard organ bath techniques, rings of human umbilical arteries (HUA) without endothelium were contracted by serotonin (5-HT, 1 microM), histamine (10 microM) and potassium chloride (KCl, 30 and 60 mM), and the vasorelaxant effect of testosterone was analysed. Testosterone (100 microM) relaxed human umbilical arteries contracted with 5-HT (30.1 +/- 3.2%), histamine (55.1 +/- 2.6%), KCl 30 mM (52.9 +/- 8.3%) and KCl 60 mM (54.8 +/- 6.3%). Flutamide (10 microM), an inhibitor of classical intracellular testosterone receptor, and glibenclamide, an ATP-sensitive potassium-channels (K(ATP)) inhibitor, did not influence the testosterone relaxant effect. 4-aminopyridine, a voltage-sensitive potassium-channels (Kv) inhibitor, decreased the effect of testosterone on histamine- and 5-HT-contracted arteries. Tetraethylammonium (TEA), which inhibits Kv channels and large-conductance Ca(2+)-activated potassium channels (BK(Ca)), decreased the effect of testosterone on KCl (60 mM)-contracted and 5-HT-contracted HUA. In conclusion, testosterone induces relaxation of HUA, and this effect does not appear to be mediated via a classic intracellular testosterone receptor-dependent mechanism. Our results suggest that this relaxation is partially mediated by activation of BK(Ca) and K(V) channels. The involvement of these two channels in testosterone-relaxant mechanism is dependent on the pathways activated by the contractile agent used.

Pre-Eclampsia and Eclampsia: An Update on the Pharmacological Treatment Applied in Portugal

Abstract: Pre-eclampsia and eclampsia are two hypertensive disorders of pregnancy, considered major causes of maternal and perinatal death worldwide. Pre-eclampsia is a multisystemic disease characterized by the development of hypertension after 20 weeks of gestation, with the presence of proteinuria or, in its absence, of signs or symptoms indicative of target organ injury. Eclampsia represents the consequence of brain injuries caused by pre-eclampsia. The correct diagnosis and classification of the disease are essential, since the therapies for the mild and severe forms of pre-eclampsia are different. Thus, this review aims to describe the most advisable antepartum pharmacotherapy for pre-eclampsia and eclampsia applied in Portugal and based on several national and international available guidelines. Slow-release nifedipine is the most recommended drug for mild pre-eclampsia, and labetalol is the drug of choice for the severe form of the disease. Magnesium sulfate is used to prevent seizures caused by eclampsia. Corticosteroids are used for fetal lung maturation. Overall, the pharmacological prevention of these diseases is limited to low-dose aspirin, so it is important to establish the safest and most effective available treatment.

Plastic and Human Health: A Micro Issue?

Abstract: Microplastics are a pollutant of environmental concern Their presence in food destined for human consumption and in air samples has been reported Thus, microplastic exposure via diet or inhalation could occur, the human health effects of which are unknown The current review article draws upon cross-disciplinary scientific literature to discuss and evaluate the potential human health impacts of microplastics and outlines urgent areas for future research Key literature up to September 2016 relating to accumulation, particle toxicity, and chemical and microbial contaminants was critically examined Although microplastics and human health is an emerging field, complementary existing fields indicate potential particle, chemical and microbial hazards If inhaled or ingested, microplastics may accumulate and exert localized particle toxicity by inducing or enhancing an immune response Chemical toxicity could occur due to the localized leaching of component monomers, endogenous additives, and adsorbed enviro

Discerning the Chemistry in Individual Organelles with Small-Molecule Fluorescent Probes.

Abstract: Principle has it that even the most advanced super-resolution microscope would be futile in providing biological insight into subcellular matrices without well-designed fluorescent tags/probes. Developments in biology have increasingly been boosted by advances of chemistry, with one prominent example being small-molecule fluorescent probes that not only allow cellular-level imaging, but also subcellular imaging. A majority, if not all, of the chemical/biological events take place inside cellular organelles, and researchers have been shifting their attention towards these substructures with the help of fluorescence techniques. This Review summarizes the existing fluorescent probes that target chemical/biological events within a single organelle. More importantly, organelle-anchoring strategies are described and emphasized to inspire the design of new generations of fluorescent probes, before concluding with future prospects on the possible further development of chemical biology.

Physiological roles of K^+ channels in vascular smooth muscle cells(Hirosi Kuriyama Award 2007 Memorial Review)

Abstract: In this review, we present the basic properties, physiological functions, regulation, and pathological alterations of four major classes of K+ channels that have been detected in vascular smooth muscle cells. Voltage-dependent K+ (Kv) channels open upon depolarization of the plasma membrane in vascular smooth muscle cells. The subsequent efflux of K+ through the channels induces repolarization to the resting membrane potential. Changes in the intracellular Ca2+ concentration and membrane depolarization stimulate large-conductance Ca2+-activated K+ (BKCa) channels, which are thought to play an important role in maintaining the membrane potential. ATP-sensitive K+ (K(ATP)) channels underscore the functional bond between cellular metabolism and membrane excitability. The blockade of KATP channel function results in vasoconstriction and depolarization in various types of vascular smooth muscle. Inward rectifier K+ (Kir) channels, which are expressed in smooth muscle of the small-diameter arteries, contribute to the resting membrane potential and basal tone. Kir channel activation has been shown to raise the extracellular K+ concentration to 10-15 mM, resulting in vasodilation. Each of K+ channels listed above is responsive to a number of vasoconstrictors and vasodilators, which act through protein kinase C (PKC) and protein kinase A (PKA), respectively. Impaired Kv, KATP, and Kir channel functions has been linked to a number of pathological conditions, which may lead to vasoconstriction.

Testosterone and metabolic syndrome: a meta-analysis study

Abstract: INTRODUCTION Metabolic syndrome (MetS) is often associated with male hypogonadism. Despite the well-known link, the role of testosterone replacement therapy (TRT) in MetS has not been completely clarified. AIM To systematically analyse the relationship between androgen levels and MetS we performed a review and meta-analyses of available prospective and cross-sectional studies. In addition, a specific meta-analysis on the metabolic effects of TRT in available randomized clinical trials (RCTs) was also performed. METHODS An extensive Medline search was performed including the following words "testosterone,""metabolic syndrome," and "males". MAIN OUTCOME MEASURES Out of 323 retrieved articles, 302 articles were excluded for different reasons. Among the 20 published studies included, 13, 3, and 4 were cross-sectional, longitudinal, and RCTs, respectively. Another unpublished RCT was retrieved on http://www.clinicaltrials.gov. RESULTS MetS patients showed significantly lower T plasma levels, as compared with healthy individuals. Similar results were obtained when MetS subjects with and without erectile dysfunction were analyzed separately or when NCEP-ATPIII MetS criteria were compared with other definitions. Meta-regression analysis demonstrated that type 2 diabetes (T2DM) increased the MetS-associated T fall. In a multiple regression model, after adjusting for age and BMI, both T2DM and MetS independently predicted low testosterone (adj. r = -0.752; P < 0.001 and -0.271; P < 0.05, respectively). Analysis of longitudinal studies demonstrated that baseline testosterone was significantly lower among patients with incident MetS in comparison with controls (2.17 [-2.41;-1.94] nmol/L; P < 0.0001). Combining the results of RCTs, TRT was associated with a significant reduction of fasting plasma glucose, homeostatic model assessment index, triglycerides, and waist circumference. In addition, an increase of high-density lipoprotein cholesterol was also observed. CONCLUSIONS The meta-analysis of the available cross-sectional data suggests that MetS can be considered an independent association of male hypogonadism. Although only few RCTs have been reported, TRT seems to improve metabolic control, as well as central obesity.

Molecular Physiology of Membrane Guanylyl Cyclase Receptors

Abstract: cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl c...