Showing posts with label Advanced Articles. Show all posts
Showing posts with label Advanced Articles. Show all posts

Monday, 24 September 2007

Stem cells: science, policy, and ethics

American Society for Clinical Investigation
2004 November 15; 114(10): 1364–1370.


Gerald D. Fischbach and Ruth L. Fischbach



Human embryonic stem cells offer the promise of a new regenerative medicine in which damaged adult cells can be replaced with new cells. Research is needed to determine the most viable stem cell lines and reliable ways to promote the differentiation of pluripotent stem cells into specific cell types (neurons, muscle cells, etc.). To create new cell lines, it is necessary to destroy preimplantation blastocysts. This has led to an intense debate that threatens to limit embryonic stem cell research. The profound ethical issues raised call for informed, dispassionate debate.

Friday, 14 September 2007

Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field

Institute of Veterinary Biochemistry and Molecular Biology, University of Zurich

Sarah W. Kamau, Paul O. Hassa, Benedikt Steitz1, Alke Petri-Fink1, Heinrich Hofmann1,Margarethe Hofmann-Amtenbrink2, Brigitte von Rechenberg3 and Michael O. Hottiger*

Nucleic Acids Research, 2006, Vol. 34, No. 5 e40
doi:10.1093/nar/gkl035


New approaches to increase the efficiencyofnon-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) containing sequence encoding for green fluorescent protein were coupled to polyethylenimine coated superparamagnetic nanoparticles (SPIONs). The complexes were added to cells that were subsequently exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency 40 times more than in cells not exposed to the magnetic field. The transfection efficiency was highest when the nanoparticles were sedimented on the permanentmagnet before the application of the pulsating field, both for small (50 nm) and large (200–250 nm) nanoparticles. The highly efficient gene transfer already within 5 min shows that this technique is a powerful tool for future in vivo studies, where rapid gene delivery is requiredbefore systemic clearance or filtration of the gene vectors occurs.
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