Vital marker for muscle nuclei in myoblast transfer

A new method is developed using Fluoro-Gold (FG) as a vital stain to label the nuclei of donor myoblasts in myoblast transfer studies. In vitro incubation with 0.01% FG for 16 h resulted in 100% nuclei labelling. Intensive fluorescence persisted following 9 days of subculture, when the human myoblasts were injected into the quadriceps of mouse recipients immunosuppressed with cyclosporine. Injected muscles showed mosaicism of host and donor nuclei 25 days after injection, indicating (i) survival and fusion among donor myoblasts, and (ii) fusion between host and donor cells. FG labelling was not observed in control muscles injected with an equal volume of FG-labelled dead myoblasts, 0.01% FG medium, or phosphate-buffered saline.Key words: Fluoro-Gold, nucleus vital stain, myoblast culture and transplant.

The polarization of electrons by double scattering

The scattering of electrons by gold, xenon and krypton atoms has been investigated using Dirac’s equations. The polarization to be expected by double scattering at 90° has been studied for an energy range 100 to 150.000 eV. The results agree substantially in the energy range 10,000- 150.000 eV with those obtained by Mott for an unscreened gold nucleus. It is found, however, that for lower energies the effect of screening is more im ­ portant. In particular, at energies for which the intensity of single scattering at 90° is near a minimum, a large polarization is to be expected in the case of gold. For xenon the polarization never exceeds 4 % and for krypton 2 %. Modifications of the interaction between a nucleus and electron which would reduce the polarization are considered. As an example of a field as different as possible from the Coulomb type, the polarization produced in double scattering by a potential ‘well’ is investigated in detail.