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- Asif, Sana, M.D, PhD student, et al.
(author)
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Validation of an MPC polymer coating to reduce surface-induced cascade system activation in whole blood in in vitroand in vivo models
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Other publication (other academic/artistic)abstract
- ABSTRACTBackground: Artificial surfaces that come into contact with blood (e.g., when used in various forms of biomedical device) induce an immediate activation of the cascade systems of the blood, the coagulation and complement systems. These reactions may lead to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Multiple strategies to dampen these reactions have been employed, with heparin conjugation to the material surface being the most successfulthus far. Another approach to improving hemocompatibility is to use 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer coatings.Experimental: In the present study, we evaluated the effectiveness of MPC polymer coating and compared it to a commercially available heparin coating in various in vitromodels using fresh human blood with the aim to replace the costly heparin-coated equipment with the more economic MPC. We then investigated the stability of the various coatings in human plasma in vitrofor 2 weeks. Finally, we inserted MPC polymer-coated catheters into the external jugular vein of pigs and monitored the catheters’ antithrombotic properties for 4 days.Results: 1) There was no significant activation of platelets and of the coagulation and complement systems on the MPC polymer-coated or the commercially available heparin surface. 2) Both coats were superior in hemocompatibility to non-coated matrix surfaces. 3) The protective effect of the MPC polymer coat did not decline after incubation in plasma for up to 2 weeks. 4) With MPC polymer-coated catheters, it was possible to easily draw blood from experimental animals for 4 days, in contrast to the case for heparin-flushed commercially available non-coated catheters, in which substantial clotting was seen.
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- Karlsson, Christofer M. G., et al.
(author)
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Metatranscriptomic analysis uncovers divergent responses of Baltic Sea bacteria to forest and agriculture river loadings
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Other publication (other academic/artistic)abstract
- Climate change is predicted to induce substantial changes in precipitation patterns across the globe. In Northern Europe, precipitation is expected to increase more than the global average (particularly in northern Scandinavia), causing increased river runoff. The Baltic Sea is one of the largest brackish environments on earth with a catchment area that spans 14 countries, encompassing primarily forested areas and agricultural landscapes. Despite the acknowledged role of marine bacteria in nutrient cycling, there is a lack of knowledge in their metabolic responses to inorganic and organic nutrient loading from riverine runoff. We investigated the bacterial growth and gene expression responses in a mesocosm experiment in which river water from boreal forest- (enriched in humic substances) or agriculture- influenced catchment areas were added to Baltic Sea Proper water. The riverine nutrient input triggered extensive phytoplankton blooms and bacterial growth, most notably in the agriculture river treatment. Interestingly, bacterial gene expression analysis (metatranscriptomics) showed similar responses to agriculture and humic river inputs at the start of the experiment (before the phytoplankton bloom), but expression patterns diverged significantly upon bloom senescence.Notably, transcripts associated with phosphate metabolism were significantly enriched , whereas transcripts related to nitrogen metabolism were significantly lower in the agriculture river treatment compared to the boreal forest river treatment. The opposite pattern was observed in the boreal forest river water treatment. Overall, our results showed that interactions between river nutrient loading and phytoplankton organic matter are important in regulating bacterial activities and responses at the molecular level. This suggests that bacterial transformations of organic matter and nutrient cycling in coastal waters and estuarine environments are sensitive to changes in precipitation patterns in a catchment area-dependent manner.
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