The OpenPicoAmp : an open-source planar lipid bilayer amplifier for hands-on learning of neuroscience

Neuroscience education can be promoted by the availability of low cost and engaging teaching materials. To address this issue, we developed an open-source lipid bilayer amplifier, the OpenPicoAmp, which is appropriate for use in introductory courses in biophysics or neurosciences dealing with the electrical properties of the cell membrane. The amplifier is designed using the common lithographic printed circuit board fabrication process and off-the-shelf electronic components. In addition, we propose a specific design for experimental chambers allowing the insertion of a commercially available polytetrafluoroethylene film. This experimental setup can be used in simple experiments in which students monitor the bilayer formation by capacitance measurement and record unitary currents produced by ionic channels like gramicidin A. Used in combination with a low-cost data acquisition board this system provides a complete solution for hands-on lessons, therefore improving the effectiveness in teaching basic neurosciences or biophysics.Comment: 13 pages, 6 figures and supplementary information (9 files including one movie). Added references, added figure, corrected typos, corrected board components list, more detailled implementation documen

Graphical Models of Psychosocial Factors in Chronic Somatic Diseases

AbstractIn this paper we describe a graph, tree and forest model of psychosocial factors dependencies of chronically ill patients, called graphical models. Foundation of the study was the theory of meaningfulness of suffering by V. E. Frankl. 181 patients with either arterial hypertension or neoplasms with bad prognosis were examined thrice: 0-10 days from the time of diagnosis (stage I), about 5 weeks from the diagnosis (stage II) and at a follow-up about 5 months since stage II (stage III). 75 factors were available for consideration: 17 in stage I, 28 in stage II, 27 in stage III and 4 sets of data that describe populations: age, gender, education, number of stages executed. For both diseases graphs and trees are built under assumption that factors are vertices and significant correlations are edges, leading to model of dependencies between factors. Usefulness of this approach to analysis of difference between diseases is discussed

Comment on “Physics at the Molecular and Cellular Level (P@MCL): A New Curriculum for Introductory Physics”

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Motivating Premedical Students to Get Interested in Physics

Physics teachers around the world are trying to create classroom environments that would allow life science students to be more intrinsically motivated in their work. These efforts include, among others, matching classroom activities to students' interests as well as structurally variable activities to match different student abilities. While physics instruction at the Université libre de Bruxelles also strives to make classes more relevant for life science students, two stimulation approaches will be presented here in detail. These include the in-class motivation using historical examples of physicians' role in physics development and the small group work outside of class on physics problems that have engaging, motivating, and challenging biomedical headings.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Ion permeability of artificial membranes evaluated by diffusion potential and electrical resistance measurements

In the presentarticle, a novel model of artificial membranes that provides efficientassistance in teaching the origins of diffusion potentials is proposed.These membranes are made of polycarbonate filters fixed to 12-mmplastic rings and then saturated with a mixture of creosol and n-decane.The electrical resistance and potential difference across these membranescan be easily measured using a low-cost volt-ohm meter and home-madeAg/AgCl electrodes. The advantage of the model is the lack of ionicselectivity of the membrane, which can be modified by the introductionof different ionophores to the organic liquid mixture. A membrane treatedwith the mixture containing valinomycin generates voltages from -53 to -25 mV in the presence of a 10-fold KCl gradient (in to out) and from-79 to -53 mV in the presence of a bi-ionic KCl/NaCl gradient (in toout). This latter bi-ionic gradient potential reverses to a value from +9 to +20 mV when monensin is present in the organic liquid mixture. Thus,the model can be build stepwise, i.e. all factors leading to the developmentof diffusion potentials can be introduced sequentially, helpingstudents to understand the quantitative relationships of ionic gradients anddifferential membrane permeability in the generation of cell electrical signals. © 2013 The American Physiological Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The OpenPicoAmp-100k: an open-source high-performance amplifier for single channel recording in planar lipid bilayers

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Relevance of carnosic acid to the treatment of several health disorders: Molecular targets and mechanisms

Carnosic acid is a phenolic diterperne compound found in abundance in sage and rosemary, which are both widely used in traditional medicine. Research over the past decade indicates that carnosic acid has multiple bioactive properties including antioxidant, anti-inflammatory and anticancer activities among others. This review summarizes the current in vitro and in vivo data about the efficacy of carnosic acid in the prevention or treatment of various experimental health disorders. The analysis of the literature allows an insight into the participation of numerous signaling pathways modulated by carnosic acid, into its synergistic potential and, thus, into the divergence in cellular mechanisms of action of this molecule.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Possible role of lysophosphatidic acid in rat model of hypoxic pulmonary vascular remodeling

Pulmonary hypertension is characterized by cellular and structural changes in the vascular wall of pulmonary arteries. We hypothesized that lysophosphatidic acid (LPA), a bioactive lipid, is implicated in this vascular remodeling in a rat model of hypoxic pulmonary hypertension. Exposure of Wistar rats to 10% O2 for 3 weeks induced an increase in the mean serum levels of LPA, to 40.9 (log-detransformed standard deviations: 23.4 -71.7) μM versus 21.6 (11.0-42.3) μM in a matched control animal group (P = 0.037). We also observed perivascular LPA immunohistochemical staining in lungs of hypoxic rats colocalized with the secreted lysophospholipase D autotaxin (ATX). Moreover, ATX colocalized with mast cell tryptase, suggesting implication of these cells in perivascular LPA production. Hypoxic rat lungs expressed more ATX transcripts (2.4-fold) and more transcripts of proteins implicated in cell migration: β2 integrin (1.74-fold), intracellular adhesion molecule 1 (ICAM-1; 1.84-fold), and αM integrin (2.70-fold). Serum from the hypoxic group of animals had significantly higher chemoattractant properties toward rat primary lung fibroblasts, and this increase in cell migration could be prevented by the LPA receptor 1 and 3 antagonists. LPA also increased adhesive properties of human pulmonary artery endothelial cells as well as those of human peripheral blood mononuclear cells, via the activation of LPA receptor 1 or 3 followed by the stimulation of gene expression of ICAM-1, β-1, E-selectin, and vascular cell adhesion molecule integrins. In conclusion, chronic hypoxia increases circulating and tissue levels of LPA, which might induce fibroblast migration and recruitment of mononuclear cells in pulmonary vasculature, both of which contribute to pulmonary vascular remodeling.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Modulation of epithelial Na+ channel activity by long-chain n-3 fatty acids.

The epithelial sodium channel is found in apical membranes of a variety of native epithelial tissues, where it regulates sodium and fluid balance. In vivo, a number of hormones and other endogenous factors, including polyunsaturated fatty acids (PUFAs), regulate these channels. We tested the effects of essential n-3 and n-6 PUFAs on amiloride-sensitive sodium transport in A6 epithelial cells. Eicosapentaenoic acid [EPA; C20:5(n-3)] transiently stimulated amiloride-sensitive open-circuit current (I(Na)) from 4.0 +/- 0.3 to 7.7 +/- 0.3 microA/cm2 within 30 min (P < 0.001). No activation was seen in the presence of 10 microM amiloride. In cell-attached but not in cell-excised patches, EPA acutely increased the open probability of sodium channels from 0.45 +/- 0.08 to 0.63 +/- 0.10 (P = 0.02, paired t-test). n-6 PUFAs, including linoleic acid (C18:2), eicosatetraynoic acid (C20:4), and docosapentanoic acid (C22:5) had no effect, whereas n-3 docosahexanoic acid (C22:6) activated amiloride-sensitive I(Na) in a manner similar to EPA. Activation of I(Na) by EPA was prevented by H-89, a PKA inhibitor. Similarly, PKA activity was stimulated by EPA. Nonspecific stimulation of phosphodiesterase activity by CoCl2 completely prevented the effect of EPA on sodium transport. We conclude that n-3 PUFAs activate epithelial sodium channels downstream of cAMP in a cAMP-dependent pathway also involving PKA.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe