10,470 research outputs found
Visualization of membrane loss during the shrinkage of giant vesicles under electropulsation
We study the effect of permeabilizing electric fields applied to two
different types of giant unilamellar vesicles, the first formed from EggPC
lipids and the second formed from DOPC lipids. Experiments on vesicles of both
lipid types show a decrease in vesicle radius which is interpreted as being due
to lipid loss during the permeabilization process. We show that the decrease in
size can be qualitatively explained as a loss of lipid area which is
proportional to the area of the vesicle which is permeabilized. Three possible
mechanisms responsible for lipid loss were directly observed: pore formation,
vesicle formation and tubule formation.Comment: Final published versio
Glucocorticoid receptor gene inactivation in dopamine-innervated areas selectively decreases behavioral responses to amphetamine
Peer reviewedPublisher PD
Lâapport dâune perspective gĂ©nĂ©tique Ă lâanalyse des images scientifiques
Ă partir dâĂ©tudes ethnographiques menĂ©es dans des laboratoires appartenant Ă deux disciplines des sciences de la nature, la physique des matĂ©riaux et la pharmacologie, Catherine Allamel-Raffin Ă©labore une classification des images produites dans ces domaines de recherche en les envisageant sous lâangle de leur production, câest-Ă -dire en adoptant une perspective gĂ©nĂ©tique. Cette dĂ©marche conduit notamment au constat suivant : certaines images massivement prĂ©Âsentes en pharmacologie (histogrammes), et peu prĂ©sentes en physique des matĂ©riaux, soulĂšvent des problĂšmes sĂ©miotiques particuliers quâil est possible dâanalyser Ă lâaide des travaux de E. Tufte. Le recours Ă une perspective gĂ©nĂ©tique, dans un second temps, permet de relever les similitudes, mais Ă©galement dâĂ©tablir les distinctions qui sâimposent quant aux processus de rĂ©alisation de ces images : la prĂ©sence potentielle dâartefacts, ceux-ci Ă©tant situĂ©s Ă des moments diffĂ©rents du cours de lâexpĂ©rimentation, la non-existence dâune flexibilitĂ© interprĂ©tative dans le cas des images produites en pharmacologie Ă lâopposĂ© de ce que lâon rencontre en physique des matĂ©riaux, lâĂ©volution du statut Ă©pistĂ©mique de certaines images au cours de la recherche grĂące au recours, couronnĂ© de succĂšs, Ă des stratĂ©gies expĂ©rimentales dĂ©terminĂ©es.Catherine Allamel-Raffin proposes a classification of scientific images produced in two different fields of the natural sciences (pharmacology and surface sciences). This classification relies upon ethnographic studies. The point of view adopted here is a genetic one, in other words, these ethnographic studies especially focus on the processes which lead to the production of images in two different laboratories. In the first part of my contribution, I will show that certain types of images particularly well represented in pharmacology (but not in surface sciences) like histograms, generate some specific semiotic problems. These semiotic problems will be approached by referring to the E. Tufteâs work. In the second part of my contribution, I will show that this genetic point of view leads us to underline the similarities but also the differences which take place all along the productionâs processes of the images: the possible existence of artifacts which are not situated, in the two laboratories, at the same levels of the experiment; the fact that there is no interpretative flexibility in pharmacology contrasting with the interpretative flexibility one can observe in surface sciences; the evolution of the epistemic status of some images based on the successful use of determined experimental strategies
Case studies in a flipped classroom: An approach to support nursing learning in pharmacology and pathophysiology. - Ătudes de cas dans une classe inversĂ©e : une approche pour appuyer lâapprentissage de la pharmacologie et de la physiopathologie en sciences infirmiĂšres.
Background: Comprehensive understanding of pharmacology and pathophysiology is required for safe and effective use of medications in patient care. Case studies are an active learning strategy that can develop higher level learning. The use of case studies as a learning strategy in pharmacology and pathophysiology has not been assessed in nursing students.
Methods: Undergraduate nursing students were surveyed to determine their perceptions of the use of case studies as a learning strategy in pharmacology and pathophysiology. Average responses to statements created for the study were measured using a Likert scale and differences were determined using ANOVA. Exploratory Factor Analysis of the data was performed.
Results: Participants reported that the utilization of case studies enhanced knowledge acquisition and application in pharmacology and pathophysiology. Participants recommended the use of case studies as a learning strategy. Factor analysis produced two factors. Factor 1 was designated self-efficacy and critical reasoning around pathophysiology and pharmacology in patient care. Factor 2 was designated as attitude toward the learning model.
Conclusion: Case studies engage students and are a potential tool for effective nursing education. Nursing students believe that case studies help to develop higher level learning when studying pharmacology and pathophysiology. A tool was developed that demonstrates potential for accurately measuring student attitudes towards a learning strategy and the impact of the learning strategy on nursing studentsâ self-efficacy related to pharmacology and pathophysiology.
Résumé
Contexte : une comprĂ©hension exhaustive de la pharmacologie et de la physiopathologie est nĂ©cessaire pour une utilisation sĂ©curitaire et efficace des mĂ©dicaments dans les soins aux patients. Les Ă©tudes de cas constituent une stratĂ©gie dâapprentissage actif qui permet de passer Ă un niveau dâapprentissage supĂ©rieur. L\u27utilisation des Ă©tudes de cas comme stratĂ©gie dâapprentissage de la pharmacologie et de la physiopathologie nâa pas Ă©tĂ© Ă©valuĂ©e chez les Ă©tudiantes en sciences infirmiĂšres.
MĂ©thodes : Un sondage a Ă©tĂ© menĂ© auprĂšs dâĂ©tudiantes de premier cycle en sciences infirmiĂšres afin de recueillir leur perception de lâutilisation des Ă©tudes de cas comme stratĂ©gie dâapprentissage de la pharmacologie et de la physiopathologie. Les moyennes des rĂ©ponses obtenues aux Ă©noncĂ©s dĂ©veloppĂ©s pour lâĂ©tude ont Ă©tĂ© mesurĂ©es Ă l\u27aide de l\u27Ă©chelle de Likert et les diffĂ©rences ont Ă©tĂ© dĂ©terminĂ©es Ă l\u27aide de lâanalyse de variance (ANOVA). Une analyse factorielle exploratoire des donnĂ©es a Ă©tĂ© effectuĂ©e.
RĂ©sultats : les participantes ont indiquĂ© que lâutilisation des Ă©tudes de cas a permis dâamĂ©liorer lâacquisition et lâapplication des connaissances en pharmacologie et en physiopathologie. Les participantes ont recommandĂ© lâutilisation des Ă©tudes de cas Ă titre de stratĂ©gie dâapprentissage. Lâanalyse factorielle a produit deux facteurs. Le facteur 1 a Ă©tĂ© dĂ©signĂ© comme lâauto-efficacitĂ© et le raisonnement critique entourant la pharmacologie et la physiopathologie dans les soins aux patients. Le facteur 2 a Ă©tĂ© dĂ©signĂ© comme lâattitude envers le modĂšle dâapprentissage.
Conclusion : les Ă©tudes de cas mobilisent les Ă©tudiantes et constituent un outil potentiel pour une formation efficace en sciences infirmiĂšres. Les Ă©tudiantes estiment que les Ă©tudes de cas contribuent Ă un apprentissage de niveau supĂ©rieur dans lâĂ©tude de la pharmacologie et de la physiopathologie. Lâoutil a conçu pour lâĂ©tude prĂ©sente un potentiel comme mesure juste de lâattitude des Ă©tudiantes envers une stratĂ©gie dâapprentissage et des rĂ©percussions de la stratĂ©gie dâapprentissage sur lâauto-efficacitĂ© des Ă©tudiantes en lien avec la pharmacologie et la physiopathologie
Comment to the Paper of Michael J. Saxton: "A Biological Interpretation of Transient Anomalous Subdiffusion. I. Qualitative Model"
In a recent paper, Michael J. Saxton proposes to interpret as anomalous
diffusion the occurrence of apparent transient sub-diffusive regimes in
mean-squared displacements (MSD) plots, calculated from experimental
trajectories of molecules diffusing in living cells, acquired by Single
Particle (or Molecule) Tracking techniques (SPT or SMT). In this Comment,
without questioning the existence of sub-diffusive behaviors, which certainly
play a key role in numbers of mechanisms in living systems, we point out that
the data used by J.M. Saxton can as well be fitted by a simple law, resulting
from confined diffusion at short times, with a slower free diffusion
superimposed at larger times. When visualizing MSD plots, the transition from
short-term diffusion confined in domains of size L, to slower, longer-term free
diffusion, can be confused with anomalous diffusion over several orders of
magnitude of time.Comment: To appear in Biophysical Journa
Cellular mechanisms of potassium homeostasis in the mammalian nervous system
Double-barrelled ion-sensitive microelectrodes were used to measure changes in the intracellular activities of K+, Na+, and Cl- (aKi, aNai, aCli) in neurones of rat sympathetic ganglia and in glial cells of slices from guinea-pig olfactory cortex. In sympathetic neurones, carbachol and gamma-aminobutyric acid (GABA) produced a reversible decrease of aKi. The decrease of aKi during carbachol was accompanied by a rise of aNai, whereas in the presence of GABA decreases of aKi and aCli were seen. The reuptake of K+ released during the action of carbachol was completely blocked by ouabain, whereas furosemide inhibited the aKi recovery after the action of GABA. In glial cells, in contrast to the observations in the sympathetic neurones, aKi and aCli increased, whereas aNai decreased when neuronal activity was enhanced by repetitive stimulation of the lateral olfactory tract. It was found that barium ions and ouabain strongly reduced the activity-related rise of intraglial aKi in slices of guinea-pig olfactory cortex. These data show that mammalian neurones as well as glial cells possess several K+ uptake mechanisms that contribute to potassium homeostasis. Ouabain, furosemide, and Ba2+ are useful pharmacological tools to separate these mechanisms
Suivi thérapeutique de l'imatinib
* Le monitoring (suivi) joue un rÎle important pour un traitement et son évaluation - pour autant qu'il se base sur la mesure de marqueurs cliniques adéquats ou de substituts validés.
* Pour ce qui est du traitement d'imatinib, le «therapeutic drug monitoring» (TDM) semble ĂȘtre une option utile pour le contrĂŽle du traitement de la LMC. Il utilise la concentration plasmatique de ce mĂ©dicament comme marqueur.
* Les concentrations plasmatiques d'imatinib varient considĂ©rablement d'un patient Ă l'autre sous un mĂȘme schĂ©ma posologique, en raison de la variabilitĂ© interindividuelle de sa pharmacocinĂ©tique. Il a Ă©tĂ© dĂ©montrĂ© que l'exposition plasmatique Ă©tait en corrĂ©lation avec le rĂ©sultat clinique des patients LMC - aussi bien pour la rĂ©ponse au traitement que pour le profil d'effets indĂ©sirables.
* Il n'est pas encore Ă©tabli si le TDM de l'imatinib doit ĂȘtre utilisĂ© que dans le cas de problĂšmes cliniques ou si les patients LMC peuvent dĂ©jĂ profiter d'un contrĂŽle prĂ©ventif systĂ©matique «de routine» - de maniĂšre Ă garder la concentration plasmatique dans des marges thĂ©rapeutiques. Cela est toujours plus recommandĂ© ces derniers temps.
* Pour répondre à cette question, une étude suisse prospective, randomisée et contrÎlée recrute des patients LMC traités par imatinib depuis moins de 5 ans et propose en outre le TDM pour tous les patients en cas de problÚmes cliniques.
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* Monitoring spielt eine wichtige Rolle zur Therapieevaluierung und Behandlungsentscheidung - solange es auf der Basis der Messung von entsprechenden klinischen oder validierten Surrogat-Markern stattfindet.
* Im Hinblick auf die Imatinib-Therapie scheint das «Therapeutische Drug-Monitoring» (TDM) ein nĂŒtzlicher Ansatz zum Therapie-Monitoring der CML-Behandlung zu sein, welches die Plasmakonzentration des Arzneimittels als Marker zur TherapieĂŒberwachung verwendet.
* Imatinib-Plasmakonzentrationen variieren betrĂ€chtlich von Patient zu Patient unter dem gleichen Dosierungsschema, aufgrund der interindividuell unterschiedlichen Pharmakokinetik des Arzneimittels. FĂŒr die Plasmaexposition wurde gezeigt, dass sie mit dem klinischen Outcome von CML-Patienten korreliert - sowohl im Bezug auf das Therapieansprechen als auch auf das Nebenwirkungsprofil.
* Es ist noch unklar, ob das TDM von Imatinib nur im Falle von klinischen Problemen Verwendung finden sollte oder ob CML-Patienten bereits von einem systematischen, prÀventiven «Routine»-Monitoring zur Therapieindividualisierung - zur Steuerung der Plasmakonzentration in einen therapeutischen Bereich - profitieren könnten, welches in letzter Zeit immer hÀufiger empfohlen wird.
* Um diese Fragestellung zu beantworten, nimmt eine prospektive, randomisiert kontrollierte Schweizer Studie CML-Patienten auf, die seit weniger als 5 Jahren mit Imatinib behandelt werden, und bietet das TDM zudem fĂŒr alle Patienten im Falle von klinischen Problemen an
Quantification and Correction of Systematic Errors Due to Detector Time-Averaging in Single-Molecule Tracking Experiments
Single-molecule tracking is a powerful way to look at the dynamic
organization of plasma membranes. However, there are some limitations to its
use. For example, it was recently observed, using numerical simulation, that
time-averaging effects inherent to the exposure time of detectors are likely to
bias the apparent motion of molecules confined in microdomains. Here, we solve
this apparently limiting issue analytically. We explore this phenomenon by
calculating its effects on the observed diffusion coefficients and domain
sizes. We demonstrate that the real parameters can be easily recovered from the
measured apparent ones. Interestingly, we find that single-molecule tracking
can be used to explore events occurring at a timescale smaller than the
exposure time.Comment: 3 pages (Letter); 1 figur
No differences between men and women in adverse drug reactions related to psychotropic drugs: a survey from France, Italy and Spain
ProducciĂłn CientĂficaA large number of studies have suggested that being a woman represents a potential risk factor for the development of adverse drug reactions (ADRs). The aim of this study is to further explore the differences between men and women with regard to reported ADRs, particularly those associated with psychotropic drugs. We used spontaneous reports of suspected ADRs collected by Midi-PyrĂ©nĂ©es (France), Veneto (Italy) and Castilla y LeĂłn (Spain) Regional Pharmacovigilance Centres (January 2007-December 2009). All the reports including a psychotropic medication were selected in a first step; age distribution, seriousness and type of ADRs were compared between men and women. Reports of nonpsychotropic drugs were similarly identified and treated. The absolute number of reports and the proportion, considering population, were higher in women than in men. This was observed for all reports, but was particularly higher for psychotropic drugs (592 vs. 375; P < 0.001) than for nonpsychotropics drugs (5193 vs. 4035; P < 0.001). Antidepressants were the most reported (women, 303; men, 141; P < 0.001); the reporting rates (number of reports divided by exposed patients in the same period, estimated through sales data) for these drugs, however, were not significantly different between women (0.87 cases per 10 000 treated persons per year) and men (0.81 cases per 10 000 treated persons per year). Although there was a higher number of reports of ADRs in women, ADR reporting rates might be similar as highlighted by the case of antidepressants. Antidepressant ADRs in fact were similarly reported in men and in women. Gender differences are sometimes subtle and difficult to explore. International networks, as the one established for this study, do contribute to better analyse problems associated with medications.Junta de Castilla y LeĂłn. ConsejerĂa de Sanidad. DirecciĂłn General de Salud PĂșblica e InvestigaciĂłn, Desarrollo e InnovaciĂłn
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