83,255 research outputs found

    Potential benefits and risks of clinical xenotransplantation

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    The transplantation of organs and cells from pigs into humans could overcome the critical and continuing problem of the lack of availability of deceased human organs and cells for clinical transplantation. Developments in the genetic engineering of pigs have enabled considerable progress to be made in the experimental laboratory in overcoming the immune barriers to successful xenotransplantation. With regard to pig organ xenotransplantation, antibody- and cell-mediated rejection have largely been overcome, and the current major barrier is the development of coagulation dysregulation. This is believed to be due to a combination of immune activation of the vascular endothelial cells of the graft and molecular incompatibilities between the pig and primate coagulation-anticoagulation systems. Pigs with new genetic modifications specifically directed to this problem are now becoming available. With regard to less complex tissues, such as islets (for the treatment of diabetes), neuronal cells (for the treatment of Parkinson's disease), and corneas, the remaining barriers are less problematic, and graft survival in nonhuman primate models extends for > 1 year in all three cases. In planning the initial clinical trials, consideration will be concentrated on the risk-benefit ratio, based to a large extent on the results of preclinical studies in nonhuman primates. If the benefit to the patient is anticipated to be high, eg, insulin-independent control of glycemia, and the potential risks low, eg, minimal risk of transfer of a porcine infectious agent, then a clinical trial would be justified. © 2012 Cooper and Ayares, publisher and licensee Dove Medical Press Ltd

    Prediction of acidification and recovery on a landscape scale. Progress report 26.9.97

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    Finite-volume Hyperbolic 3-Manifolds contain immersed Quasi-Fuchsian surfaces

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    The paper contains a new proof that a complete, non-compact hyperbolic 33-manifold MM with finite volume contains an immersed, closed, quasi-Fuchsian surface.Comment: Final version to appear in AGT. Some typos corrected, particularly def (3.6). Rewording of 4 paragraphs in proof of (4.2) for added clarity. Final section added comparing this paper to the approach of Masters and Zhan

    Operation of a forced circulation, haynes alloy no. 25, mercury loop to study corrosion product separation techniques

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    Forced circulation, Haynes alloy 25, mercury loop to study corrosion product separatio

    A superior process for forming titanium hydrogen isotopic films

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    Process forms stoichiometric, continuous, strongly bonded titanium hydrogen isotopic films. Films have thermal and electrical conductivities approximately the same as bulk pure titanium, ten times greater than those of usual thin films
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