53 research outputs found

    The Equilibria of Lipid–K+ Ions in Monolayer at the Air/Water Interface

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    The effect of K+ ion interaction with monolayers of phosphatidylcholine (lecithin, PC) or cholesterol (Ch) was investigated at the air/water interface. We present surface tension measurements of lipid monolayers obtained using a Langmuir method as a function of K+ ion concentration. Measurements were carried out at 22°C using a Teflon trough and a Nima 9000 tensiometer. Interactions between lecithin and K+ ions or Ch and K+ ions result in significant deviations from the additivity rule. An equilibrium theory to describe the behavior of monolayer components at the air/water interface was developed in order to obtain the stability constants and area occupied by one molecule of lipid–K+ ion complex (LK+). The stability constants for lecithin–K+ ion (PCK+) complex, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}KPCK+=3.26×102dm3mol1 K_{{{\text{PCK}}^{ + } }} = { 3}. 2 6\times 10^{ 2} {\text{dm}}^{ 3} \,{\text{mol}}^{ - 1} \end{document}, and for cholesterol–K+ ion (ChK+) complex, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}KChK+=1.00×103dm3mol1 K_{{{\text{ChK}}^{ + } }} = { 1}.00 \times 10^{ 3} {\text{dm}}^{ 3} \,{\text{mol}}^{ - 1} \end{document}, were calculated by inserting the experimental data. The value of area occupied by one PCK+ complex is 60 Å2 molecule−1, while the area occupied by one ChK+ complex is 40.9 Å2 molecule−1. The complex formation energy (Gibbs free energy) values for the PCK+ and ChK+ complexes are −14.18 ± 0.71 and −16.92 ± 0.85 kJ mol−1, respectively

    Potent Cardioprotective Effect of the 4-Anilinoquinazoline Derivative PD153035: Involvement of Mitochondrial KATP Channel Activation

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    Background: The aim of the present study was to evaluate the protective effects of the 4-anilinoquinazoline derivative PD153035 on cardiac ischemia/reperfusion and mitochondrial function. Methodology/Principal Findings: Perfused rat hearts and cardiac HL-1 cells were used to determine cardioprotective effects of PD153035. Isolated rat heart mitochondria were studied to uncover mechanisms of cardioprotection. Nanomolar doses of PD153035 strongly protect against heart and cardiomyocyte damage induced by ischemia/reperfusion and cyanide/aglycemia. PD153035 did not alter oxidative phosphorylation, nor directly prevent Ca(2+) induced mitochondrial membrane permeability transition. The protective effect of PD153035 on HL-1 cells was also independent of AKT phosphorylation state. Interestingly, PD153035 activated K(+) transport in isolated mitochondria, in a manner prevented by ATP and 5-hydroxydecanoate, inhibitors of mitochondrial ATP-sensitive K(+) channels (mitoK(ATP)). 5-Hydroxydecanoate also inhibited the cardioprotective effect of PD153035 in cardiac HL-1 cells, demonstrating that this protection is dependent on mitoK(ATP) activation. Conclusions/Significance: We conclude that PD153035 is a potent cardioprotective compound and acts in a mechanism involving mitoK(ATP) activation

    Epigenetic Regulation of Fatty Acid Amide Hydrolase in Alzheimer Disease

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    OBJECTIVE: Alzheimer disease (AD) is a progressive, degenerative and irreversible neurological disorder with few therapies available. In search for new potential targets, increasing evidence suggests a role for the endocannabinoid system (ECS) in the regulation of neurodegenerative processes. METHODS: We have studied the gene expression status and the epigenetic regulation of ECS components in peripheral blood mononuclear cells (PBMCs) of subjects with late-onset AD (LOAD) and age-matched controls (CT). RESULTS: We found an increase in fatty acid amide hydrolase (faah) gene expression in LOAD subjects (2.30 ± 0.48) when compared to CT (1.00 ± 0.14; *p<0.05) and no changes in the mRNA levels of any other gene of ECS elements. Consistently, we also observed in LOAD subjects an increase in FAAH protein levels (CT: 0.75 ± 0.04; LOAD: 1.11 ± 0.15; *p<0.05) and activity (pmol/min per mg protein CT: 103.80 ± 8.73; LOAD: 125.10 ± 4.00; *p<0.05), as well as a reduction in DNA methylation at faah gene promoter (CT: 55.90 ± 4.60%; LOAD: 41.20 ± 4.90%; *p<0.05). CONCLUSIONS: Present findings suggest the involvement of FAAH in the pathogenesis of AD, highlighting the importance of epigenetic mechanisms in enzyme regulation; they also point to FAAH as a new potential biomarker for AD in easily accessible peripheral cells

    A Quantitative Analytical Method to Test for Salt Effects on Giant Unilamellar Vesicles

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    Today, free-standing membranes, i.e. liposomes and vesicles, are used in a multitude of applications, e.g. as drug delivery devices and artificial cell models. Because current laboratory techniques do not allow handling of large sample sizes, systematic and quantitative studies on the impact of different effectors, e.g. electrolytes, are limited. In this work, we evaluated the Hofmeister effects of ten alkali metal halides on giant unilamellar vesicles made of palmitoyloleoylphosphatidylcholine for a large sample size by combining the highly parallel water-in-oil emulsion transfer vesicle preparation method with automatic haemocytometry. We found that this new quantitative screening method is highly reliable and consistent with previously reported results. Thus, this method may provide a significant methodological advance in analysis of effects on free-standing model membranes

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Monte Carlo modeling applied to studies of quantum cascade lasers

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    Sphingolipids as cell fate regulators in lung development and disease

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    Development and characterization of biocompatible isotropic and anisotropic oil-in-water colloidal dispersions as a new delivery system for methyl dihydrojasmonate antitumor drug

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    Gisela Bevilacqua Rolfsen Ferreira da Silva,1 Maria Virginia Scarpa,1 Gustavo Rossanezi,1 Eryvaldo Socrates Tabosa do Egito,2 Anselmo Gomes de Oliveira1 1Departamento de F&aacute;rmacos e Medicamentos, Universidade Estadual Paulista (UNESP), Araraquara, SP, Brazil; 2Laborat&oacute;rio de Sistemas Dispersos, Universidade Federal do Rio Grande do Norte (UFRN) Natal, RN, Brazil Abstract: Microemulsions (MEs) are colloidal systems that can be used for drug-delivery and drug-targeting purposes. These systems are able to incorporate drugs modifying bioavailability and stability and reducing toxic effects. The jasmonate compounds belong to a group of plant stress hormones, and the jasmonic acid and its methyl ester derivative have been described as having anticancer activity. However, these compounds are very poorly water-soluble, not allowing administration by an intravenous route without an efficient nanostructured carrier system. In this work, biocompatible MEs of appropriate diameter size for intravenous route administration, loaded and unloaded with methyl dihydrojasmonate (MJ), were developed and described in a pseudo-ternary phase diagram. The compositions of the MEs were carefully selected from their own regions in the pseudo-ternary phase diagram. The formulations were analyzed by light scattering, polarized light microscopy, and X-ray diffraction. Also, a study on rheological profile was performed. The results showed that the droplet size decreased with both MJ incorporation and oil phase/surfactant ratio. All compositions of the studied MEs showed rheological behavior of pseudoplastic fluid and amorphous structures. In the absence of MJ, most of the studied MEs had thixotropic characteristics, which became antithixotropic in the presence of the drug. Almost all MJ-unloaded MEs presented anisotropic characteristics, but some formulations became isotropic, especially in the presence of MJ. The results of this study support the conclusion that the studied system represents a promising vehicle for in vivo administration of the MJ antitumor drug. Keywords: methyl dihydrojasmonate, anticancer drug, biocompatible microemulsions, pseudo-ternary phase diagram, microemulsion characterizatio

    Oil-in-water biocompatible microemulsion as a carrier for the antitumor drug compound methyl dihydrojasmonate

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    Gisela Bevilacqua Rolfsen Ferreira da Silva,1 Maria Virginia Scarpa,1 Iracilda Zepone Carlos,2 Marcela Bassi Quilles,2 Raphael Carlos Comeli Lia,3 Eryvaldo Socrates Tabosa do Egito,4 Anselmo Gomes de Oliveira1 1Departamento de F&aacute;rmacos e Medicamentos, 2Departamento de An&aacute;lises Cl&iacute;nicas, UNESP&ndash;Universidade Estadual Paulista, Faculdade de Ci&ecirc;ncias Farmac&ecirc;uticas, PPG em Nanotecnologia Farmac&ecirc;utica, Rodovia Araraquara-Ja&uacute; Km 01, Araraquara, SP, Brazil; 3Instituto de Patologia Cir&uacute;rgica e Citopatologia (IPC), Araraquara, SP, Brazil; 4UFRN&ndash;Universidade Federal do Rio Grande do Norte, Programa de P&oacute;s-gradua&ccedil;&atilde;o em Ci&ecirc;ncias da Sa&uacute;de, Natal, RN, Brazil Abstract: Methyl dihydrojasmonate (MJ) has been studied because of its application as an antitumor drug compound. However, as MJ is a poorly water-soluble compound, a suitable oil-in-water microemulsion (ME) has been studied in order to provide its solubilization in an aqueous media and to allow its administration by the parenteral route. The ME used in this work was characterized on the pseudo-ternary phase diagram by dynamic light scattering and rheological measurements. Regardless of the drug presence, the droplet size was directly dependent on the oil/surfactant (O/S) ratio. Furthermore, the drug incorporation into the ME significantly increased the ME diameter, mainly at low O/S ratios. The rheological evaluation of the systems showed that in the absence of drug a Newtonian behavior was observed. On the other hand, in the presence of MJ the ME systems revealed pseudoplastic behavior, independently of the O/S ratio. The in vivo studies demonstrated that not only was the effect on the tumor inhibition inversely dependent on the MJ-loaded ME administered dose, but also it was slightly higher than the doxorubicin alone, which was used as the positive control. Additionally, a small antiangiogenic effect for MJ-loaded ME was found at doses in which it possesses antitumor activity. MJ revealed to be nontoxic at doses higher than 350&nbsp;mg/kg, which was higher than the dose that provides tumor-inhibition effect in this study. Because the MJ-loaded ME was shown to have anticancer activity comparable to doxorubicin, the ME described here may be considered a suitable vehicle for parenteral administration of MJ. Keywords: antitumor drug, nanocarrier, angiogenesis inhibition, antitumor activity, Ehrlich ascitic tumo

    Presentation and Outcome of Pancreaticoduodenal Endocrine Tumors in Multiple Endocrine Neoplasia Type 1 Syndrome

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    Aim: To assess presentation and outcome of pancreaticoduodenal endocrine tumors (PDETs) in a single center series of multiple endocrine neoplasia type 1 (MEN1) patients. Methods: Retrospective analysis of prospectively collected data of MEN1 patients observed at the University of Verona. Results: Thirty-one MEN1 patients had PDETs, including 16 nonfunctioning (NF), 6 insulinomas and 9 Zollinger-Ellison syndrome (ZES). In 16 of these patients (52%), PDET was the manifestation which led to the diagnosis of MEN1; among this group, 15 patients (94%) previously had unidentified primary hyperparathyroidism (PHPT), which was asymptomatic in 9 cases (60%). Of the 31 patients, 19 (61%) underwent curativesurgery and 13 (68%, 7 NF-PDETs, 4 insulinomas and 2 ZES) were disease-free after a median follow-up of 3 years (range: 0.5-15). One patient had debulking surgery with stable disease after 2 years of follow-up. Eight patients with NF-PDETs 6420 mm and 2 with ZES, treated with a conservative approach, showed stable disease. One patient with insulinoma was lost to follow-up. Conclusions: PDET may be the manifestation that leads to MEN1 diagnosis since the almost constant presence of PHPT is very often unrecognized or considered sporadic. Conversely, the presence of PDETs should be looked for in all patients presenting PHPT, even if asymptomatic, particularly before age 50. Surgery may be curative in the majority of insulinomas and can prolong disease-free survival in NF-PDET, but is not proven to be effective in ZES. A conservative approach can be safely reserved for patients with NF-PDETs 6420 mm
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