Subtractive proteomic mapping of the endothelial surface in lung and solid tumours for tissue-specific therapy

The molecular complexity of tissues and the inaccessibility of most cells within a tissue limit the discovery of key targets for tissue-specific delivery of therapeutic and imaging agents in vivo. Here, we describe a hypothesis-driven, systems biology approach to identifying a small subset of proteins induced at the tissue-blood interface that are inherently accessible to antibodies injected intravenously. We use subcellular fractionation, subtractive proteomics and bioinformatics to identify endothelial cell surface proteins exhibiting restricted tissue distribution and apparent tissue modulation. Expression profiling and gamma-scintigraphic imaging with antibodies establishes two of these proteins, aminopeptidase-P and annexin A1, as selective in vivo targets for antibodies in lungs and solid tumours, respectively. Radio-immunotherapy to annexin A1 destroys tumours and increases animal survival. This analytical strategy can map tissue- and disease-specific expression of endothelial cell surface proteins to uncover novel accessible targets useful for imaging and therapy.     

An enigmatic long-lasting gamma-ray burst not accompanied by a bright supernova

Gamma-ray bursts (GRBs) are short, intense flashes of soft gamma-rays coming from the distant Universe. Long-duration GRBs (those lasting more than approximately 2 s) are believed to originate from the deaths of massive stars, mainly on the basis of a handful of solid associations between GRBs and supernovae. GRB 060614, one of the closest GRBs discovered, consisted of a 5-s hard spike followed by softer, brighter emission that lasted for approximately 100 s (refs 8, 9). Here we report deep optical observations of GRB 060614 showing no emerging supernova with absolute visual magnitude brighter than M(V) = -13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs. This demonstrates that some long-lasting GRBs can either be associated with a very faint supernova or produced by different phenomena.     

16-β-methylprednisone from hecogenin

Zusammenfassung Es wird über die Herstellung des 16-Methylprednisons berichtet, welche vom Hecogenin ausgehend über ca. 15 Stufen durchgeführt wird. Als wichtige Zwischenstufe treten 5-Pregn-16-en-3-ol-11, 20-dion-Acetat und 16-Methylen-5-pregnan-3, 17-diol-11, 20-dion auf: letzteres wird durch eine stereospezifische katalytische Reduktion in das entsprechende 16-Methyl-derivat umgewandelt.     

Diffraction-unlimited all-optical imaging and writing with a photochromic GFP

Lens-based optical microscopy failed to discern fluorescent features closer than 200?nm for decades, but the recent breaking of the diffraction resolution barrier by sequentially switching the fluorescence capability of adjacent features on and off is making nanoscale imaging routine. Reported fluorescence nanoscopy variants switch these features either with intense beams at defined positions or randomly, molecule by molecule. Here we demonstrate an optical nanoscopy that records raw data images from living cells and tissues with low levels of light. This advance has been facilitated by the generation of reversibly switchable enhanced green fluorescent protein (rsEGFP), a fluorescent protein that can be reversibly photoswitched more than a thousand times. Distributions of functional rsEGFP-fusion proteins in living bacteria and mammalian cells are imaged at <40-nanometre resolution. Dendritic spines in living brain slices are super-resolved with about a million times lower light intensities than before. The reversible switching also enables all-optical writing of features with subdiffraction size and spacings, which can be used for data storage.     

Erythropoietin-stimulated erythropoiesis in long-term bone marrow culture.

The proliferation of multipotential haematopoietic stem cells (CFU-S) is possible in some long-term bone marrow cultures. Granulocyte and macrophage progenitor (CFU-C) and megakaryocyte precursor cells (CFU-M) are present in these cultures and undergo full development into mature cells. In contrast, while immature erythroid progenitors ('early' BFU-E) are maintained in long-term culture, none of the more differentiated progeny (CFU-E) have been detected, and no morphologically recognisable erythroid cells have been observed. We now describe a modified culture system in which the 'early' BFU-E develop into 'late' BFU-E in response to added erythropoietin. Further maturation of these cells into CFU-E and non-nucleated erythrocytes can be achieved by mechanical agitation of the long-term cultures or by transferring the cells into dishes which do not allow cell attachment to occur.