The rate of X-ray-induced DNA double-strand break repair in the embryonic mouse brain is unaff ected by exposure to 50 Hz magnetic fi elds

Following in utero exposure to low dose radiation (10 – 200 mGy), we recently observed a linear induction of DNA double-strand breaks (DSB) and activation of apoptosis in the embryonic neuronal stem/progenitor cell compartment. No signifi cant induction of DSB or apoptosis was observed following exposure to magnetic fi elds (MF). In the present study, we exploited this in vivo system to examine whether exposure to MF before and after exposure to 100 mGy X-rays impacts upon DSB repair rates. Materials and methods : 53BP1 foci were quantifi ed following combined exposure to radiation and MF in the embryonic neuronal stem/progenitor cell compartment. Embryos were exposed in utero to 50 Hz MF at 300 m T for 3 h before and up to 9 h after exposure to 100 mGy X-rays. Controls included embryos exposed to MF or X-rays alone plus sham exposures. Results : Exposure to MF before and after 100 mGy X-rays did not impact upon the rate of DSB repair in the embryonic neuronal stem cell compartment compared to repair rates following radiation exposure alone. Conclusions : We conclude that in this sensitive system MF do not exert any signifi cant level of DNA damage and do not impede the repair of X-ray induced damage

Isolation and N-terminal amino acid sequence of membrane-bound human HLA-A and HLA-B antigens.

Membrane-bound HLA-A and HLA-B antigens have been extensively purified in good yield. The sequences of the N-terminal 16 amino acids have been determined using about 1 nmol of protein eluted from polyacrylamide gel after electrophoresis in sodium dodecyl sulphate

Isolation and N-terminal amino acid sequence of membrane-bound human HLA-A and HLA-B antigens.

Membrane-bound HLA-A and HLA-B antigens have been extensively purified in good yield. The sequences of the N-terminal 16 amino acids have been determined using about 1 nmol of protein eluted from polyacrylamide gel after electrophoresis in sodium dodecyl sulphate

The structure and evolution of the HLA--Bw4 and Bw6 antigens.

The HLA--Bw4 and Bw6 antigenic determinants have been shown to co-migrate with HLA--B determinants on gel-filtration, sucrose density gradient centrifugation and affinity chromatography, using Lens culinaris lectin and antibody against human beta 2 microbulin. These and other published data imply that the HLA--Bw4 and Bw6 determinants reside on the same polypeptide chain as other HLA--B locus determinants. The implications of this in terms of the evolution of cross reacting groups of antigens at the HLA--B locus are discussed

The structure and evolution of the HLA--Bw4 and Bw6 antigens.

The HLA--Bw4 and Bw6 antigenic determinants have been shown to co-migrate with HLA--B determinants on gel-filtration, sucrose density gradient centrifugation and affinity chromatography, using Lens culinaris lectin and antibody against human beta 2 microbulin. These and other published data imply that the HLA--Bw4 and Bw6 determinants reside on the same polypeptide chain as other HLA--B locus determinants. The implications of this in terms of the evolution of cross reacting groups of antigens at the HLA--B locus are discussed