17 research outputs found

    Evaluation der Kampagne "Künftige Nichtraucher” des Schweizerischen Apothekerverbands

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    Zusammenfassung: Mit dem Ziel, die Bevölkerung für das niederschwellige Beratungsangebot in Apotheken zu sensibilisieren, organisierte der Schweizerische Apothekerverband in 616 Apotheken die Kampagne "Künftige Nichtraucher”. Die Evaluation beurteilte die Beratungstätigkeit der Apotheken im Bereich Tabakentwöhnung und untersuchte die Einstellung der Projektverantwortlichen in den Apotheken gegenüber der Kampagne und der Tabakprävention. Die Dokumentation der Raucherberatungen erfolgte mittels Aktivitätsstatistik eine Woche vor und während der Aktion. Ein standardisierter Fragebogen erfasste an deren Ende die Einstellung gegenüber der Kampagne und der Tabakprävention. 32% der an der Kampagne teilnehmenden Apotheken führten die Aktivitätsstatistik. Der Rücklauf des Fragebogens zur Erfassung der Einstellung betrug 58%. Stärkster Prädiktor der Beratungshäufigkeit war die Variable "Apotheke mit mehrheitlich Passantenkundschaft”. Für die Beratungsintensität war es die Variable "Besuch des Workshops und Weiterbildung des Apothekenteams”, d. h. die bestmögliche Weiterbildung vor der Kampagne. Die positivste Einstellung gegenüber der Tabakprävention und das grösste Interesse an einer weiteren Kampagne zeigten Verantwortliche aus Apotheken mit mehrheitlich häufiger und intensiver Beratungstätigkeit. Mit der vorliegenden Studie kann gezeigt werden, dass Raucherentwöhnung in Apotheken durchführbar ist. Hauptvoraussetzungen dafür sind Motivation für die Prävention sowie eingehende Weiterbildung der Apothekerlnnen und des Apothekenteam

    Cell communication by periodic cyclic-AMP pulses

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    At the surface of aggregating cells of the slime mould, Dictyostelium discoideum, two different sites interacting with extracellular cAMP are detectable: binding sites and cyclic-nucleotide phosphodiesterase. Both sites are developmentally regulated. An adequate stimulus for the chemoreceptor system in D. discoideum is the change of cAMP concentration in time, rather than concentration per se: long-term binding of cAMP causes only a short-term response. The system is, consequently, adapted to the recognition of pulses rather than to steady-state concentrations of cAMP. The cells are, nevertheless, able to sense stationary spatial gradients and to respond to them by chemotactic orientation. The possibility is discussed that they do so by transforming spatial concentration changes into temporal ones, using extending pseudopods as sensors

    Cyclic-AMP reception and cell recognition in dictyostelium discoideum

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    Single cells of the slime mold, Dictyostelium discoideum, aggregate into a multicellular organism in response to cyclic AMP, which they detect by binding to cellsurface receptors. During the aggregation phase, two different responses to cyclic-AMP are observed. First, the cells orientate by chemotaxis towards the source of a concentration gradient which initially is a group of cells forming an aggregation center. Second, the cells relay pulses which are periodically generated by the centers

    Bidirectional transfer study of polystyrene nanoparticles across the placental barrier in an ex vivo human placental perfusion model

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    BACKGROUND: Nanoparticle exposure in utero might not be a major concern yet, but it could become more important with the increasing application of nanomaterials in consumer and medical products. Several epidemiologic and in vitro studies have shown that nanoparticles can have potential toxic effects. However, nanoparticles also offer the opportunity to develop new therapeutic strategies to treat specifically either the pregnant mother or the fetus. Previous studies mainly addressed whether nanoparticles are able to cross the placental barrier. However, the transport mechanisms underlying nanoparticle translocation across the placenta are still unknown. OBJECTIVES: In this study we examined which transport mechanisms underlie the placental transfer of nanoparticles. METHODS: We used the ex vivo human placental perfusion model to analyze the bidirectional transfer of plain and carboxylate modified polystyrene particles in a size range between 50 and 300 nm. RESULTS: We observed that the transport of polystyrene particles in the fetal to maternal direction was significantly higher than for the maternal to fetal direction. Regardless of their ability to cross the placental barrier and the direction of perfusion, all polystyrene particles accumulated in the syncytiotrophoblast of the placental tissue. CONCLUSIONS: Our results indicate that the syncytiotrophoblast is the key player in regulating nanoparticle transport across the human placenta. The main mechanism underlying this translocation is not based on passive diffusion, but is likely to involve an active, energy-dependent transport pathway. These findings will be important for reproductive toxicology as well as for pharmaceutical engineering of new drug carriers. CITATION: Grafmueller S, Manser P, Diener L, Diener PA, Maeder-Althaus X, Maurizi L, Jochum W, Krug HF, Buerki-Thurnherr T, von Mandach U, Wick P. 2015. Bidirectional transfer study of polystyrene nanoparticles across the placental barrier in an ex vivo human placental perfusion model. Environ Health Perspect 123:1280-1286; http://dx.doi.org/10.1289/ehp.1409271

    Knocking at the door of the unborn child: engineered nanoparticles at the human placental barrier

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    Exposure of pregnant women and their unborn children to engineered nanoparticles (NPs) is not yet of major public concern. However, this may soon change in light of the ever-increasing production of NPs and the continuous appearance of novel NP-containing consumer products. However, NPs may not only pose risks to exposed individuals; they offer major potential for the development of novel therapeutic strategies to treat specifically either the mother or the developing foetus. Hence there is every reason to explore the transplacental transfer of engineered NPs in more detail, and to find answers to the vast number of open questions in this fascinating field of research

    Determination of the transport rate of xenobiotics and nanomaterials across the placenta using the ex vivo human placental perfusion model

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    Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ (1). Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 (2) and continuously modified by Schneider et al. in 1972 (3), can serve as an excellent model to study the transfer of xenobiotics or particles. Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results. The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data

    Transfer studies of polystyrene nanoparticles in the ex vivo human placenta perfusion model: key sources of artifacts

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    International audienceNanotechnology is a rapidly expanding and highly promising new technology with many different fields of application. Consequently, the investigation of engineered nanoparticles in biological systems is steadily increasing. Questions about the safety of such engineered nanoparticles are very important and the most critical subject with regard to the penetration of biological barriers allowing particle distribution throughout the human body. Such translocation studies are technically challenging and many issues have to be considered to obtain meaningful and comparable results. Here we report on the transfer of polystyrene nanoparticles across the human placenta using an ex vivo human placenta perfusion model. We provide an overview of several challenges that can potentially occur in any translocation study in relation to particle size distribution, functionalization and stability of labels. In conclusion, a careful assessment of nanoparticle properties in a physiologically relevant milieu is as challenging and important as the actual study of nanoparticle-cell interactions itself
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