415 research outputs found

    Revised structure of haemoventosin

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    The structure of the lichen pigment haemoventosin has been revised to 3,4,6,9-tetrahydro-5,10-dihydroxy-7-methoxy-3S-methyl-1,6,9-trioxo-1H-naphtho-[2,3-c]pyran (3), mainly on the basis of long-range δC/δH correlations observed in 2D HMBC NMR experiments and long-range δH/δD isotope effects observed in partial deuteriation experiments with 10-O-acetylhaemoventosin; ortho- and para-quinonoid structures were distinguished by means of the transacetylation inferred in the sodium dithionite reduction of 10-O-acetylhaemoventosin

    Cytosolic delivery of nanolabels prevents their asymmetric inheritance and enables extended quantitative in vivo cell imaging

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    Long-term in vivo imaging of cells is crucial for the understanding of cellular fate in biological processes in cancer research, immunology, or in cell-based therapies such as beta cell transplantation, in type I diabetes or stem cell therapy. Traditionally, cell labeling with the desired contrast agent occurs ex vivo via spontaneous endocytosis, which is a variable and slow process that requires optimization for each particular label-cell type combination. Following endocytic uptake, the contrast agents mostly remain entrapped in the endolysosomal compartment, which leads to signal instability, cytotoxicity, and asymmetric inheritance of the labels upon cell division. Here, we demonstrate that these disadvantages can be circumvented by delivering contrast agents directly into the cytoplasm via vapor nanobubble photoporation. Compared to classic endocytic uptake, photoporation resulted in :50 and 3 times higher loading of fluorescent dextrans and quantum dots, respectively, with improved signal stability and reduced cytotoxicity: Most: interestingly, cytosolic delivery by iihotoporation prevented asymmetric inheritance of labels by daughter cells over subsequent cell' generations. Instead, unequal inheritance of endocytosed labels resulted in a dramatic increase in polydispersity of the amount of labels per cell with each cell division, hindering accurate quantification of cell numbers in vivo over time. The combined benefits of cell labeling by photoporation resulted in a marked improvement in long-term cell visibility in vivo where an insulin producing cell line (INS-1E cell line) labeled with fluorescent dextrans could be tracked for up to two months in Swiss nude mice compared to 2-Weeks for cells labeled by endocytosis

    Diabetes mellitus and the metabolic syndrome do not abolish, but might reduce, the cardioprotective effect of ischemic postconditioning

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    ObjectiveIschemic preconditioning fails to protect the diabetic heart against lethal reperfusion injury. Because the pathways of ischemic pre- and postconditioning partially overlap, we evaluated the cardioprotective effect of ischemic postconditioning in mouse models of type 2 diabetes (ObOb) and the metabolic syndrome (DKO).MethodsMice (C57BL/6J, ObOb, and DKO; aged 24 weeks; n = 24, n = 28, and n = 18, respectively) underwent reperfusion after 30 minutes of coronary occlusion with or without ischemic postconditioning (3 cycles of 10 seconds reperfusion–reocclusion). Left ventricular contractility and infarct size were assessed 60 minutes later with pressure conductance analysis and 2,3,5-triphenyl-tetrazolium chloride staining, respectively. In a second cohort (C57BL/6J and DKO; aged 12 weeks; n = 31 and n = 24, respectively) cardiac cine magnetic resonance imaging was performed after 1 and 10 weeks, followed by pressure conductance analysis and Sirius red staining.ResultsIn the C57BL6/J mice, the infarct size was lower (40%, P < 10−5) and the load independent preload recruitable stroke work was greater after ischemic postconditioning (P < .05). In the ObOb and DKO mice, ischemic postconditioning reduced the infarct size by 24% (P < 10−5). In the C57BL/6J mice, the ejection fraction was greater and the myocardial mass was lower 10 weeks after ischemic postconditioning (P < .05). Tagging grid deformation was increased after ischemic postconditioning in both infarcted and remote areas. After ischemic postconditioning, the survival and ejection fraction were greater in the DKO mice (67% vs 17% and 44% ± 11% vs 59% ± 2%, P < .05 for both), and the collagen content was lower for both C57BL/6J and DKO mice (P < .05 for both).ConclusionsThe cardioprotective effect of ischemic postconditioning was sustained in C57BL/6J mice after 10 weeks and protected against adverse left ventricular remodeling. In mouse models of type 2 diabetes, protection against lethal reperfusion injury is present, leading to increased survival after ischemia and reperfusion
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