331 research outputs found
Interior house-painting from the restoration to the Regency.
In 2 vols.Available from British Library Document Supply Centre-DSC:DX195980 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Inhibition of α4-integrin stimulates epicardial–mesenchymal transformation and alters migration and cell fate of epicardially derived mesenchyme
AbstractEpithelial–mesenchymal transformation of the embryonic epicardium produces the subepicardial mesenchyme that is essential for normal coronary vascular development. Gene targeting experiments in mice have demonstrated an essential role for α4-integrin in normal epicardial development, but the precise cellular consequences of α4-integrin loss remain uncertain. To better understand the function of α4-integrin in epicardial development, we constructed a replication-incompetent adenovirus (AdlacZα4AS) that expresses antisense chicken α4-integrin as the 3′ untranslated region of a lacZ reporter gene. This construct effectively labeled cells while greatly reducing levels of α4-integrin mRNA and protein. In quail chick chimeras, transplanted epicardial cells infected with AdlacZα4AS adhered to the heart and were incorporated into the epicardium, but 4 days after grafting, were largely absent from the epicardial epithelium, recapitulating the defect in α4-null mice. This did not result from epicardial cell apoptosis or anomalous migration of epicardial cells to extracardiac sites. Rather, AdlacZα4AS-infected epicardial cells were particularly invasive, being three to four times more likely to migrate to the interstitium of the myocardium than AdlacZ-infected epicardial cells. Accelerated epicardial–mesenchymal transformation and migration of α4-negative epicardium was observed in an organ culture system that does not require prior culture of epicardial cells. Remarkably, AdlacZα4AS infection also prevented targeting of epicardially derived mesenchyme to the media of developing coronary vasculature in the myocardial interstitium. This study provides evidence that epicardial α4-integrin normally restrains epicardial–mesenchymal transformation, invasion, and migration and is essential for correct targeting of epicardially derived mesenchyme to the developing coronary vasculature
Coupling electron capture dissociation and the modified Kendrick mass defect for sequencing of a poly(2-ethyl-2-oxazoline) polymer
With increasing focus on the structural elucidation of polymers, advanced tandem mass spectrometry techniques will play a crucial role in the characterization of these compounds. In this contribution, synthesis and analysis of methyl initiated and xan-thate terminated poly (2-ethyl-2-oxazoline) using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry was achieved. Electron capture dissociation (ECD) produced full end group characterization as well as back bone fragmentation including complete sequence coverage of the polymer. A method of fragment ion characterization is also presented with the use of the high resolution modified Kendrick mass defect plots as a means of grouping fragments from the same fragmentation pathways together. This type of data processing is applicable to all tandem mass spectrometry techniques for polymer analysis but is made more effective with high mass accuracy methods. ECD FT-ICR MS demonstrates its promising role as a structural characterization technique for polyoxazoline species
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Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. III: Measurement for Ursa Minor
This article presents a measurement of the proper motion of the Ursa Minor
dwarf spheroidal galaxy determined from images taken with the Hubble Space
Telescope in two distinct fields.Comment: AJ, accepted; 23 pages, 17 figures (Fig. 1 abridged), 5 table
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